Security Alerts

Cisco Email Security Appliance Denial of Service Vulnerability

Cisco Security Advisories - Wed, 2020-09-02 16:00

A vulnerability in the Transport Layer Security (TLS) protocol implementation of Cisco AsyncOS software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to cause high CPU usage on an affected device, resulting in a denial of service (DoS) condition.

The vulnerability is due to inefficient processing of incoming TLS traffic. An attacker could exploit this vulnerability by sending a series of crafted TLS packets to an affected device. A successful exploit could allow the attacker to trigger a prolonged state of high CPU utilization. The affected device would still be operative, but response time and overall performance may be degraded.

There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-tls-dos-xW53TBhb


Security Impact Rating: Medium
CVE: CVE-2020-3548
Categories: Security Alerts

AA20-245A: Technical Approaches to Uncovering and Remediating Malicious Activity

US-CERT - Tue, 2020-09-01 05:30
Original release date: September 1, 2020
Summary

This joint advisory is the result of a collaborative research effort by the cybersecurity authorities of five nations: Australia,[1] Canada,[2] New Zealand,[3][4] the United Kingdom,[5] and the United States.[6] It highlights technical approaches to uncovering malicious activity and includes mitigation steps according to best practices. The purpose of this report is to enhance incident response among partners and network administrators along with serving as a playbook for incident investigation.

Key Takeaways

When addressing potential incidents and applying best practice incident response procedures:

  • First, collect and remove for further analysis:
    • Relevant artifacts,
    • Logs, and
    • Data.
  • Next, implement mitigation steps that avoid tipping off the adversary that their presence in the network has been discovered.
  • Finally, consider soliciting incident response support from a third-party IT security organization to:
    • Provide subject matter expertise and technical support to the incident response,
    • Ensure that the actor is eradicated from the network, and
    • Avoid residual issues that could result in follow-up compromises once the incident is closed.

Click here for a PDF version of this report.

Technical Details

The incident response process requires a variety of technical approaches to uncover malicious activity. Incident responders should consider the following activities.

  • Indicators of Compromise (IOC) Search – Collect known-bad indicators of compromise from a broad variety of sources, and search for those indicators in network and host artifacts. Assess results for further indications of malicious activity to eliminate false positives.
  • Frequency Analysis – Leverage large datasets to calculate normal traffic patterns in both network and host systems. Use these predictive algorithms to identify activity that is inconsistent with normal patterns. Variables often considered include timing, source location, destination location, port utilization, protocol adherence, file location, integrity via hash, file size, naming convention, and other attributes.
  • Pattern Analysis – Analyze data to identify repeating patterns that are indicative of either automated mechanisms (e.g., malware, scripts) or routine human threat actor activity. Filter out the data containing normal activity and evaluate the remaining data to identify suspicious or malicious activity.
  • Anomaly Detection – Conduct an analyst review (based on the team’s knowledge of, and experience with, system administration) of collected artifacts to identify errors. Review unique values for various datasets and research associated data, where appropriate, to find anomalous activity that could be indicative of threat actor activity.
Recommended Artifact and Information Collection

When hunting and/or investigating a network, it is important to review a broad variety of artifacts to identify any suspicious activity that may be related to the incident. Consider collecting and reviewing the following artifacts throughout the investigation.

Host-Based Artifacts
  • Running Processes
  • Running Services
  • Parent-Child Process Trees
  • Integrity Hash of Background Executables
  • Installed Applications
  • Local and Domain Users
  • Unusual Authentications
  • Non-Standard Formatted Usernames
  • Listening Ports and Associated Services
  • Domain Name System (DNS) Resolution Settings and Static Routes
  • Established and Recent Network Connections
  • Run Key and other AutoRun Persistence
  • Scheduled Tasks
  • Artifacts of Execution (Prefetch and Shimcache)
  • Event logs
  • Anti-virus detections
Information to Review for Host Analysis
  • Identify any process that is not signed and is connecting to the internet looking for beaconing or significant data transfers.
  • Collect all PowerShell command line requests looking for Base64-encoded commands to help identify malicious fileless attacks.
  • Look for excessive .RAR, 7zip, or WinZip processes, especially with suspicious file names, to help discover exfiltration staging (suspicious file names include naming conventions such as, 1.zip, 2.zip, etc.).
  • Collect all user logins and look for outlier behavior, such as a time of login that is out of the ordinary for the user or a login from an Internet Protocol (IP) address not normally used by the user.
  • On Linux/Unix operating systems (OSs) and services, collect all cron and systemd /etc/passwd files looking for unusual accounts and log files, such as accounts that appear to be system / proc users but have an interactive shell such as /bin/bash rather than /bin/false/nologin
  • On Microsoft OSs, collect Scheduled Tasks, Group Policy Objects (GPO), and Windows Management Instrumentation (WMI) database storage on hosts of interest looking for malicious persistence.
  • Use the Microsoft Windows Sysinternals Autoruns tool, which allows IT security practitioners to view—and, if needed, easily disable—most programs that automatically load onto the system.
  • Check the Windows registry and Volume Shadow Copy Service for evidence of intrusion.
  • Consider blocking script files like .js, .vbs, .zip, .7z, .sfx and even Microsoft Office documents or PDFs.
  • Collect any scripts or binary ELF files from /dev/shm/tmp and /var/tmp.
  • Kernel modules listed (lsmod) for signs of a rootkit; dmesg command output can show signs of rootkit loading and device attachment amongst other things.
  • Archive contents of /var/log for all hosts.
  • Archive output from journald. These logs are pretty much the same as /var/log; however, they provide some integrity checking and are not as easy to modify. This will eventually replace the /var/log contents for some aspects of the system. Check for additional Secure Shell (SSH) keys added to user’s authorized_keys.
Network-Based Artifacts
  • Anomalous DNS traffic and activity, unexpected DNS resolution servers, unauthorized DNS zone transfers, data exfiltration through DNS, and changes to host files
  • Remote Desktop Protocol (RDP), virtual private network (VPN) sessions, SSH terminal connections, and other remote abilities to evaluate for inbound connections, unapproved third-party tools, cleartext information, and unauthorized lateral movement
  • Uniform Resource Identifier (URI) strings, user agent strings, and proxy enforcement actions for abusive, suspicious, or malicious website access
  • Hypertext Transfer Protocol Secure/Secure Sockets Layer (HTTPS/SSL)
  • Unauthorized connections to known threat indicators
  • Telnet
  • Internet Relay Chat (IRC)
  • File Transfer Protocol (FTP)
Information to Review for Network Analysis
  • Look for new connections on previously unused ports.
  • Look for traffic patterns related to time, frequency, and byte count of the connections.
  • Preserve proxy logs. Add in the URI parameters to the event log if possible.
  • Disable LLMNR on the corporate network; if unable to disable, collect LLMNR (UDP port 5355) and NetBIOS-NS (UDP port 137).
  • Review changes to routing tables, such as weighting, static entries, gateways, and peer relationships.
Common Mistakes in Incident Handling

After determining that a system or multiple systems may be compromised, system administrators and/or system owners are often tempted to take immediate actions. Although well intentioned to limit the damage of the compromise, some of those actions have the adverse effect of:

  1. Modifying volatile data that could give a sense of what has been done; and
  2. Tipping the threat actor that the victim organization is aware of the compromise and forcing the actor to either hide their tracks or take more damaging actions (like detonating ransomware).

Below—and partially listed in figure 1—are actions to avoid taking and some of the consequence of taking such actions.

  • Mitigating the affected systems before responders can protect and recover data
    • This can cause the loss of volatile data such as memory and other host-based artifacts.
    • The adversary may notice and change their tactics, techniques, and procedures.
  • Touching adversary infrastructure (Pinging, NSlookup, Browsing, etc.)
    • These actions can tip off the adversary that they have been detected.
  • Preemptively blocking adversary infrastructure
    • Network infrastructure is fairly inexpensive. An adversary can easily change to new command and control infrastructure, and you will lose visibility of their activity.
  • Preemptive credential resets
    • Adversary likely has multiple credentials, or worse, has access to your entire Active Directory.
    • Adversary will use other credentials, create new credentials, or forge tickets.
  • Failure to preserve or collect log data that could be critical to identifying access to the compromised systems
    • If critical log types are not collected, or are not retained for a sufficient length of time, key information about the incident may not be determinable. Retain log data for at least one year.
  • Communicating over the same network as the incident response is being conducted (ensure all communications are held out-of-band)
  • Only fixing the symptoms, not the root cause
    • Playing “whack-a-mole” by blocking an IP address—without taking steps to determine what the binary is and how it got there—leaves the adversary an opportunity to change tactics and retain access to the network.

Figure 1: Common missteps to be avoided when responding to an incident

Mitigations

The following recommendations and best practices may be helpful during the investigation and remediation process. Note: Although this guidance provides best practices to mitigate common attack vectors, organizations should specific to [Client]’s network should tailor mitigations specific to their network.

General Mitigation Guidance Restrict or Discontinue Use of FTP and Telnet Services

The FTP and Telnet protocols transmit credentials in cleartext, which are susceptible to being intercepted. To mitigate this risk, discontinue FTP and Telnet services by moving to more secure file storage/file transfer and remote access services.

  • Evaluate business needs and justifications to host files on alternative Secure File Transfer Protocol (SFTP) or HTTPS-based public sites.
  • Use Secure Shell (SSH) for access to remote devices and servers.
Restrict or Discontinue Use of Non-approved VPN Services
  • Investigate the business needs and justification for allowing traffic from non-approved VPN services.
  • Identify such services across the enterprise and develop measures to add the application and browser plugins that enable non-approved VPN services to the denylist.
  • Enhance endpoint monitoring to obtain visibility on devices with non-approved VPN services running. Enhanced endpoint monitoring and detection capabilities would enable an organization’s IT security personnel to manage approved software as well as identify and remove any instances of unapproved software.
Shut down or Decommission Unused Services and Systems
  • Cyber actors regularly identify servers that are out of date or end of life (EOL) to gain access to a network and perform malicious activities. These present easy and safe locations to maintain persistence on a network.
  • Often these services and servers are systems that have begun decommissioning, but the final stage has not been completed by shutting down the system. This means they are still running and vulnerable to compromise.
  • Ensuring that decommissioning of systems has been completed or taking appropriate action to remove them from the network limits their susceptibility and reduces the investigative surface to be analyzed.
Quarantine and Reimage Compromised Hosts

Note: proceed with caution to avoid the adverse effects detailed in the Common Mistakes in Incident Handling section above.

  • Reimage or remove any compromised systems found on the network.
  • Monitor and educate users to be cautious of any downloads from third-party sites or vendors.
  • Block the known bad domains and add a web content filtering capability to block malicious sites by category to prevent future compromise.
  • Sanitize removable media and investigate network shares accessible by users.
  • Improve existing network-based malware detection tools with sandboxing capabilities.
Disable Unnecessary Ports, Protocols, and Services
  • Identify and disable ports, protocols, and services not needed for official business to prevent would-be attackers from moving laterally to exploit vulnerabilities. This includes external communications as well as communications between networks.
  • Document allowed ports and protocols at the enterprise level.
  • Restrict inbound and outbound access to ports and protocols not justified for business use.
  • Restrict allowed access list to assets justified by business use.
  • Enable a firewall log for inbound and outbound network traffic as well as allowed and denied traffic.
Restrict or Disable Interactive Login for Service Accounts

Service accounts are privileged accounts dedicated to certain services to perform activities related to the service or application without being tied to a single domain user. Given that services tend to be privileged accounts and thereby have administrative privileges, they are often a target for attackers aiming to obtain credentials. Interactive login to a service account not directly tied to an end-user account makes it difficult to identify accountability during cyber incidents.

  • Audit the Active Directory (AD) to identify and document active service accounts.
  • Restrict use of service accounts using AD group policy.
  • Disallow interactive login by adding service account to a group of non-interactive login users.
  • Continuously monitor service account activities by enhancing logging.
  • Rotate service accounts and apply password best practices without service, degradation, or disruption.
Disable Unnecessary Remote Network Administration Tools
  • If an attacker (or malware) gains access to a remote user’s computer, steals authentication data (login/password), hijacks an active remote administration session, or successfully attacks a vulnerability in the remote administration tool’s software, the attacker (or malware) will gain unrestricted control of the enterprise network environment. Attackers can use compromised hosts as a relay server for reverse connections, which could enable them to connect to these remote administration tools from anywhere.
  • Remove all remote administration tools that are not required for day-to-day IT operations. Closely monitor and log events for each remote-control session required by department IT operations.
Manage Unsecure Remote Desktop Services

Allowing unrestricted RDP access can increase opportunities for malicious activity such as on path and Pass-the-Hash (PtH) attacks.

  • Implement secure remote desktop gateway solutions.
  • Restrict RDP service trust across multiple network zones.
  • Implement privileged account monitoring and short time password lease for RDP service use.
  • Implement enhanced and continuous monitoring of RDP services by enabling logging and ensure RDP logins are captured in the logs.
Credential Reset and Access Policy Review

Credential resets need to be done to strategically ensure that all the compromised accounts and devices are included and to reduce the likelihood that the attacker is able to adapt in response to this.

  • Force password resets; revoke and issue new certificates for affected accounts/devices.
  • If it is suspected that the attacker has gained access to the Domain Controller, then the passwords for all local accounts—such as Guest, HelpAssistant, DefaultAccount, System, Administrator, and kbrtgt—should be reset. It is essential that the password for the kbrtgt account is reset as this account is responsible for handling Kerberos ticket requests as well as encrypting and signing them. The account should be reset twice (as the account has a two-password history).
    • The first account reset for the kbrtgt needs to be allowed to replicate prior to the second reset to avoid any issues.
  • If it is suspected that the ntds.dit file has been exfiltrated, then all domain user passwords will need to be reset.
  • Review access policies to temporarily revoke privileges/access for affected accounts/devices. If it is necessary to not alert the attacker (e.g., for intelligence purposes), then privileges can be reduced for affected accounts/devices to “contain” them.
Patch Vulnerabilities

Attackers frequently exploit software or hardware vulnerabilities to gain access to a targeted system.

  • Known vulnerabilities in external facing devices and servers should be patched immediately, starting with the point of compromise, if known.
    • Ensure external-facing devices have not been previously compromised while going through the patching process.
  • If the point of compromise (i.e., the specific software, device, server) is known, but how the software, device, or server was exploited is unknown, notify the vendor so they can begin analysis and develop a new patch.
  • Follow vendor remediation guidance including the installation of new patches as soon as they become available.
General Recommendations and Best Practices Prior to an Incident

Properly implemented defensive techniques and programs make it more difficult for a threat actor to gain access to a network and remain persistent yet undetected. When an effective defensive program is in place, attackers should encounter complex defensive barriers. Attacker activity should also trigger detection and prevention mechanisms that enable organizations to identify, contain, and respond to the intrusion quickly. There is no single technique, program, or set of defensive techniques or programs that will completely prevent all attacks. The network administrator should adopt and implement multiple defensive techniques and programs in a layered approach to provide a complex barrier to entry, increase the likelihood of detection, and decrease the likelihood of a successful attack. This layered mitigation approach is known as defense-in-depth.

User Education

End users are the frontline security of the organizations. Educating them in security principles as well as actions to take and not take during an incident will increase the organization’s resilience and might prevent easily avoidable compromises.

  • Educate users to be cautious of any downloads from third-party sites or vendors.
  • Train users on recognizing phishing emails. There are several systems and services (free and otherwise) that can be deployed or leveraged.
  • Train users on identifying which groups/individuals to contact when they suspect an incident.
  • Train users on the actions they can and cannot take if they suspect an incident and why (some users will attempt to remediate and might make things worst).
Allowlisting
  • Enable application directory allowlisting through Microsoft Software Restriction Policy or AppLocker.
  • Use directory allowlisting rather than attempting to list every possible permutation of applications in a network environment. Safe defaults allow applications to run from PROGRAMFILES, PROGRAMFILES(X86), and SYSTEM32. Disallow all other locations unless an exception is granted.
  • Prevent the execution of unauthorized software by using application allowlisting as part of the OS installation and security hardening process.
Account Control
  • Decrease a threat actor’s ability to access key network resources by implementing the principle of least privilege.
  • Limit the ability of a local administrator account to log in from a local interactive session (e.g., Deny access to this computer from the network) and prevent access via an RDP session.
  • Remove unnecessary accounts and groups; restrict root access.
  • Control and limit local administration; e.g. implementing Just Enough Administration (JEA), just-in-time (JIT) administration, or enforcing PowerShell Constrained Language mode via a User Mode Code Integrity (UMCI) policy.
  • Make use of the Protected Users Active Directory group in Windows domains to further secure privileged user accounts against pass-the-hash attacks.
Backups
  • Identify what data is essential to keeping operations running; make regular backup copies.
  • Test that backups are working to ensure they can restore the data in the event of an incident.
  • Create offline backups to help recover from a ransomware attack or from disasters (fire, flooding, etc.).
  • Securely store offline backups at an offsite location. If feasible, choose an offsite location that is at a distance from the primary location that would be unaffected in the event of a regional natural disaster.
Workstation Management
  • Create and deploy a secure system baseline image to all workstations.
  • Mitigate potential exploitation by threat actors by following a normal patching cycle for all OSs, applications, and software, with exceptions for emergency patches.
  • Apply asset and patch management processes.
  • Reduce the number of cached credentials to one (if a laptop) or zero (if a desktop or fixed asset).
Host-Based Intrusion Detection / Endpoint Detection and Response
  • Configure and monitor workstation system logs through a host-based endpoint detection and response platform and firewall.
  • Deploy an anti-malware solution on workstations to prevent spyware, adware, and malware as part of the OS security baseline.
    • Ensure that your anti-malware solution remains up to date.
  • Monitor antivirus scan results on a regular basis.
Server Management
  • Create a secure system baseline image and deploy it to all servers.
  • Upgrade or decommission end-of-life non-Windows servers.
  • Upgrade or decommission servers running Windows Server 2003 or older versions.
  • Implement asset and patch management processes.
  • Audit for and disable unnecessary services.
Server Configuration and Logging
  • Establish remote server logging and retention.
  • Reduce the number of cached credentials to zero.
  • Configure and monitor system logs via a centralized security information and event management (SIEM) appliance.
  • Add an explicit DENY for %USERPROFILE%.
  • Restrict egress web traffic from servers.
  • In Windows environments, use Restricted Admin mode or remote credential guard to further secure remote desktop sessions against pass-the-hash attacks.
  • Restrict anonymous shares.
  • Limit remote access by only using jump servers for such access.
  • On Linux, use SELINUX or AppArmor in enforcing mode and/or turn on audit logging.
  • Turn on bash shell logging; ship this and all logs to a remote server.
  • Do not allow users to use su. Use Sudo -l instead.
  • Configure automatic updates in yum or apt.
  • Mount /var/tmp and /tmp as noexec.
Change Control
  • Create a change control process for all implemented changes.
Network Security
  • Implement an intrusion detection system (IDS).
    • Apply continuous monitoring.
    • Send alerts to a SIEM tool.
    • Monitor internal activity (this tool may use the same tap points as the netflow generation tools).
  • Employ netflow capture.
    • Set a minimum retention period of 180 days.
    • Capture netflow on all ingress and egress points of network segments, not just at the Managed Trusted Internet Protocol Services or Trusted Internet Connections locations.
  • Capture all network traffic
    • Retain captured traffic for a minimum of 24 hours.
    • Capture traffic on all ingress and egress points of the network.
  • Use VPN
    • Maintain site-to-site VPN with customers and vendors.
    • Authenticate users utilizing site-to-site VPNs.
    • Use authentication, authorization, and accounting for controlling network access.
    • Require smartcard authentication to an HTTPS page in order to control access. Authentication should also require explicit rostering of permitted smartcard distinguished names to enhance the security posture on both networks participating in the site-to-site VPN.
  • Establish appropriate secure tunneling protocol and encryption.
  • Strengthen router configuration (e.g., avoid enabling remote management over the internet and using default IP ranges, automatically log out after configuring routers, and use encryption.).
  • Turn off Wi-Fi protected setup, enforce the use of strong passwords, and keep router firmware up-to-date.
  • Improve firewall security (e.g., enable automatic updates, revise firewall rules as appropriate, implement allowlists, establish packet filtering, enforce the use of strong passwords, encrypt networks).
    • Whenever possible, ensure access to network devices via external or untrusted networks (specifically the internet) is disabled.
  • Manage access to the internet (e.g., providing internet access from only devices/accounts that need it, proxying all connections, disabling internet access for privileged/administrator accounts, enabling policies that restrict internet access using a blocklist, a resource allowlist, content type, etc.)
    • Conduct regular vulnerability scans of the internal and external networks and hosted content to identify and mitigate vulnerabilities.
    • Define areas within the network that should be segmented to increase the visibility of lateral movement by a threat and increase the defense-in-depth posture.
    • Develop a process to block traffic to IP addresses and domain names that have been identified as being used to aid previous attacks.
  • Evaluate and consider the security configurations of Microsoft Office 365 (O365) and other cloud collaboration service platforms prior to deployment.
    • Use multi-factor authentication. This is the best mitigation technique to protect against credential theft for O365 administrators and users.
    • Protect Global Admins from compromise and use the principle of “Least Privilege.”
    • Enable unified audit logging in the Security and Compliance Center.
    • Enable alerting capabilities.
    • Integrate with organizational SIEM solutions.
    • Disable legacy email protocols, if not required, or limit their use to specific users.
Network Infrastructure Recommendations
  • Create a secure system baseline image and deploy it to all networking equipment (e.g., switches, routers, firewalls).
  • Remove unnecessary OS files from the internetwork operating system (IOS). This will limit the possible targets of persistence (i.e., files to embed malicious code) if the device is compromised and will align with National Security Agency Network Device Integrity best practices.
  • Remove vulnerable IOS OS files (i.e., older iterations) from the device’s boot variable (i.e., show boot or show bootvar).
  • Update to the latest available operating system for IOS devices.
  • On devices with a Secure Sockets Layer VPN enabled, routinely verify customized web objects against the organization’s known good files for such VPNs, to ensure the devices remain free of unauthorized modification.
  • Ensure that any incident response tools that point to external domains are either removed or updated to point to internal security tools. If this is not done and an external domain to which a tool points expires, a malicious threat actor may register it and start collecting telemetry from the infrastructure.
Host Recommendations
  • Implement policies to block workstation-to-workstation RDP connections through a Group Policy Object on Windows, or by a similar mechanism.
  • Store system logs of mission critical systems for at least one year within a SIEM tool.
  • Review the configuration of application logs to verify that recorded fields will contribute to an incident response investigation.
User Management
  • Reduce the number of domain and enterprise administrator accounts.
  • Create non-privileged accounts for privileged users and ensure they use the non- privileged accounts for all non-privileged access (e.g., web browsing, email access).
  • If possible, use technical methods to detect or prevent browsing by privileged accounts (authentication to web proxies would enable blocking of Domain Administrators).
  • Use two-factor authentication (e.g., security tokens for remote access and access to any sensitive data repositories).
  • If soft tokens are used, they should not exist on the same device that is requesting remote access (e.g., a laptop) and instead should be on a smartphone, token, or other out-of-band device.
  • Create privileged role tracking.
  • Create a change control process for all privilege escalations and role changes on user accounts.
  • Enable alerts on privilege escalations and role changes.
  • Log privileged user changes in the network environment and create an alert for unusual events.
  • Establish least privilege controls.
  • Implement a security-awareness training program.
Segregate Networks and Functions

Proper network segmentation is a very effective security mechanism to prevent an intruder from propagating exploits or laterally moving around an internal network. On a poorly segmented network, intruders are able to extend their impact to control critical devices or gain access to sensitive data and intellectual property. Security architects must consider the overall infrastructure layout, segmentation, and segregation. Segregation separates network segments based on role and functionality. A securely segregated network can contain malicious occurrences, reducing the impact from intruders, in the event that they have gained a foothold somewhere inside the network.

Physical Separation of Sensitive Information

Local Area Network (LAN) segments are separated by traditional network devices such as routers. Routers are placed between networks to create boundaries, increase the number of broadcast domains, and effectively filter users’ broadcast traffic. These boundaries can be used to contain security breaches by restricting traffic to separate segments and can even shut down segments of the network during an intrusion, restricting adversary access.

Recommendations:

  • Implement Principles of Least Privilege and need-to-know when designing network segments.
  • Separate sensitive information and security requirements into network segments.
  • Apply security recommendations and secure configurations to all network segments and network layers.
Virtual Separation of Sensitive Information

As technologies change, new strategies are developed to improve IT efficiencies and network security controls. Virtual separation is the logical isolation of networks on the same physical network. The same physical segmentation design principles apply to virtual segmentation but no additional hardware is required. Existing technologies can be used to prevent an intruder from breaching other internal network segments.

Recommendations:

  • Use Private Virtual LANs to isolate a user from the rest of the broadcast domains.
  • Use Virtual Routing and Forwarding (VRF) technology to segment network traffic over multiple routing tables simultaneously on a single router.
  • Use VPNs to securely extend a host/network by tunneling through public or private networks.
Additional Best Practices
  • Implement a vulnerability assessment and remediation program.
  • Encrypt all sensitive data in transit and at rest.
  • Create an insider threat program.
  • Assign additional personnel to review logging and alerting data.
  • Complete independent security (not compliance) audits.
  • Create an information sharing program.
  • Complete and maintain network and system documentation to aid in timely incident response, including:
    • Network diagrams,
    •  Asset owners,
    • Type of asset, and
    • An up-to-date incident response plan.
Resources References Revisions
  • September 1, 2020: Initial Version

This product is provided subject to this Notification and this Privacy & Use policy.

Categories: Security Alerts

Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability

Cisco Security Advisories - Sat, 2020-08-29 03:00

A vulnerability in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to exhaust process memory of an affected device.

The vulnerability is due to insufficient queue management for Internet Group Management Protocol (IGMP) packets. An attacker could exploit this vulnerability by sending crafted IGMP traffic to an affected device. A successful exploit could allow the attacker to cause memory exhaustion, resulting in instability of other processes. These processes may include, but are not limited to, interior and exterior routing protocols.

Cisco will release software updates that address this vulnerability. There are no workarounds that address this vulnerability. There are multiple mitigations available to customers depending on their needs.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dvmrp-memexh-dSmpdvfz


Security Impact Rating: High
CVE: CVE-2020-3566
Categories: Security Alerts

Cisco NX-OS Software CLI Arbitrary Command Injection Vulnerability

Cisco Security Advisories - Wed, 2020-08-26 20:48

A vulnerability in the CLI of Cisco NX-OS Software could allow an authenticated, local attacker to perform a command-injection attack on an affected device.

The vulnerability is due to insufficient input validation of command arguments. An attacker could exploit this vulnerability by injecting malicious command arguments into a vulnerable CLI command. A successful exploit could allow the attacker, authenticated as a privileged user, to execute arbitrary commands with root privileges.

Note: On products that support multiple virtual device contexts (VDC), this vulnerability could allow an attacker to access files from any VDC.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180620-nx-os-cli-injection

This advisory is part of the June 2018 Cisco FXOS and NX-OS Software Security Advisory Collection, which includes 24 Cisco Security Advisories that describe 24 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: June 2018 Cisco FXOS and NX-OS Software Security Advisory Collection.


Security Impact Rating: High
CVE: CVE-2018-0307
Categories: Security Alerts

Cisco NX-OS Software CLI Arbitrary Command Execution Vulnerability

Cisco Security Advisories - Wed, 2020-08-26 20:48

A vulnerability in the CLI parser of Cisco NX-OS Software could allow an authenticated, local attacker to perform a command-injection attack on an affected device.

The vulnerability is due to insufficient input validation of command arguments. An attacker could exploit this vulnerability by injecting malicious command arguments into a vulnerable CLI command. A successful exploit could allow the attacker to execute arbitrary commands with root privileges on the affected device.

Note: This vulnerability requires that any feature license is uploaded to the device. The vulnerability does not require that the license be used.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180620-nx-os-cli-execution

This advisory is part of the June 2018 Cisco FXOS and NX-OS Software Security Advisory Collection, which includes 24 Cisco Security Advisories that describe 24 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: June 2018 Cisco FXOS and NX-OS Software Security Advisory Collection.


Security Impact Rating: High
CVE: CVE-2018-0306
Categories: Security Alerts

Cisco NX-OS Software Call Home Command Injection Vulnerability

Cisco Security Advisories - Wed, 2020-08-26 16:00

A vulnerability in the Call Home feature of Cisco NX-OS Software could allow an authenticated, remote attacker to inject arbitrary commands that could be executed with root privileges on the underlying operating system (OS).

The vulnerability is due to insufficient input validation of specific Call Home configuration parameters when the software is configured for transport method HTTP. An attacker could exploit this vulnerability by modifying parameters within the Call Home configuration on an affected device. A successful exploit could allow the attacker to execute arbitrary commands with root privileges on the underlying OS.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-callhome-cmdinj-zkxzSCY

This advisory is part of the August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication, which includes seven Cisco Security Advisories that describe seven vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.


Security Impact Rating: High
CVE: CVE-2020-3454
Categories: Security Alerts

Cisco UCS Manager Software Local Management CLI Denial of Service Vulnerability

Cisco Security Advisories - Wed, 2020-08-26 16:00

A vulnerability in the local management (local-mgmt) CLI of Cisco UCS Manager Software could allow an authenticated, local attacker to cause a denial of service (DoS) condition on an affected device.

The vulnerability is due to improper handling of CLI command parameters. An attacker could exploit this vulnerability by executing specific commands on the local-mgmt CLI on an affected device. A successful exploit could allow the attacker to cause internal system processes to fail to terminate properly, which could result in a buildup of stuck processes and lead to slowness in accessing the UCS Manager CLI and web UI. A sustained attack may result in a restart of internal UCS Manager processes and a temporary loss of access to the UCS Manager CLI and web UI.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucs-cli-dos-GQUxCnTe


Security Impact Rating: Medium
CVE: CVE-2020-3504
Categories: Security Alerts

Cisco NX-OS Software Border Gateway Protocol Multicast VPN Denial of Service Vulnerability

Cisco Security Advisories - Wed, 2020-08-26 16:00

A vulnerability in the Border Gateway Protocol (BGP) Multicast VPN (MVPN) implementation of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause an affected device to unexpectedly reload, resulting in a denial of service (DoS) condition.

The vulnerability is due to incomplete input validation of a specific type of BGP MVPN update message. An attacker could exploit this vulnerability by sending this specific, valid BGP MVPN update message to a targeted device. A successful exploit could allow the attacker to cause one of the BGP-related routing applications to restart multiple times, leading to a system-level restart.

Note: The Cisco implementation of BGP accepts incoming BGP traffic from only explicitly configured peers. To exploit this vulnerability, an attacker must send a specific BGP MVPN update message over an established TCP connection that appears to come from a trusted BGP peer. To do so, the attacker must obtain information about the BGP peers in the trusted network of the affected system.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxosbgp-nlri-dos-458rG2OQ

This advisory is part of the August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication, which includes seven Cisco Security Advisories that describe seven vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.


Security Impact Rating: High
CVE: CVE-2020-3397
Categories: Security Alerts

Cisco NX-OS Software Border Gateway Protocol Multicast VPN Session Denial of Service Vulnerability

Cisco Security Advisories - Wed, 2020-08-26 16:00

A vulnerability in the Border Gateway Protocol (BGP) Multicast VPN (MVPN) implementation of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a BGP session to repeatedly reset, causing a partial denial of service (DoS) condition due to the BGP session being down.

The vulnerability is due to incorrect parsing of a specific type of BGP MVPN update message. An attacker could exploit this vulnerability by sending this BGP MVPN update message to a targeted device. A successful exploit could allow the attacker to cause the BGP peer connections to reset, which could lead to BGP route instability and impact traffic. The incoming BGP MVPN update message is valid but is parsed incorrectly by the NX-OS device, which could send a corrupted BGP update to the configured BGP peer. 

Note: The Cisco implementation of BGP accepts incoming BGP traffic from only explicitly configured peers. To exploit this vulnerability, an attacker must send a specific BGP MVPN update message over an established TCP connection that appears to come from a trusted BGP peer. To do so, the attacker must obtain information about the BGP peers in the trusted network of the affected system.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxosbgp-mvpn-dos-K8kbCrJp

This advisory is part of the August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication, which includes seven Cisco Security Advisories that describe seven vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.


Security Impact Rating: High
CVE: CVE-2020-3398
Categories: Security Alerts

Cisco NX-OS Software IPv6 Protocol Independent Multicast Denial of Service Vulnerability

Cisco Security Advisories - Wed, 2020-08-26 16:00

A vulnerability in the Protocol Independent Multicast (PIM) feature for IPv6 networks (PIM6) of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.

The vulnerability is due to improper error handling when processing inbound PIM6 packets. An attacker could exploit this vulnerability by sending multiple crafted PIM6 packets to an affected device. A successful exploit could allow the attacker to cause the PIM6 application to leak system memory. Over time, this memory leak could cause the PIM6 application to stop processing legitimate PIM6 traffic, leading to a DoS condition on the affected device.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-pim-memleak-dos-tC8eP7uw

This advisory is part of the August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication, which includes seven Cisco Security Advisories that describe seven vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.


Security Impact Rating: High
CVE: CVE-2020-3338
Categories: Security Alerts

Cisco Nexus 3000 and 9000 Series Switches Privilege Escalation Vulnerability

Cisco Security Advisories - Wed, 2020-08-26 16:00

A vulnerability in the Enable Secret feature of Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an authenticated, local attacker to issue the enable command and get full administrative privileges. To exploit this vulnerability, the attacker would need to have valid credentials for the affected device.

The vulnerability is due to a logic error in the implementation of the enable command. An attacker could exploit this vulnerability by logging in to the device and issuing the enable command. A successful exploit could allow the attacker to gain full administrative privileges without using the enable password.

Note: The Enable Secret feature is disabled by default.

Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-n3n9k-priv-escal-3QhXJBC

This advisory is part of the August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication, which includes seven Cisco Security Advisories that describe seven vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.


Security Impact Rating: High
CVE: CVE-2020-3394
Categories: Security Alerts

Cisco FXOS and NX-OS Software Cisco Fabric Services Denial of Service Vulnerability

Cisco Security Advisories - Wed, 2020-08-26 16:00

A vulnerability in the Cisco Fabric Services component of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated attacker to cause process crashes, which could result in a denial of service (DoS) condition on an affected device. The attack vector is configuration dependent and could be remote or adjacent. For more information about the attack vector, see the Details section of this advisory.

The vulnerability is due to insufficient error handling when the affected software parses Cisco Fabric Services messages. An attacker could exploit this vulnerability by sending malicious Cisco Fabric Services messages to an affected device. A successful exploit could allow the attacker to cause a reload of an affected device, which could result in a DoS condition.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fxos-nxos-cfs-dos-dAmnymbd

This advisory is part of the August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication, which includes seven Cisco Security Advisories that describe seven vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.


Security Impact Rating: High
CVE: CVE-2020-3517
Categories: Security Alerts

Cisco NX-OS Software Data Management Engine Remote Code Execution Vulnerability

Cisco Security Advisories - Wed, 2020-08-26 16:00

A vulnerability in the Data Management Engine (DME) of Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to execute arbitrary code with administrative privileges or cause a denial of service (DoS) condition on an affected device.

The vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by sending a crafted Cisco Discovery Protocol packet to a Layer 2-adjacent affected device. A successful exploit could allow the attacker to execute arbitrary code with administrative privileges or cause the Cisco Discovery Protocol process to crash and restart multiple times, causing the affected device to reload and resulting in a DoS condition.

Note: Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent). Exploitation of this vulnerability also requires jumbo frames to be enabled on the interface that receives the crafted Cisco Discovery Protocol packets on the affected device.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-dme-rce-cbE3nhZS

This advisory is part of the August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication, which includes seven Cisco Security Advisories that describe seven vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.


Security Impact Rating: High
CVE: CVE-2020-3415
Categories: Security Alerts

Cisco Integrated Management Controller CSR Generation Command Injection Vulnerability

Cisco Security Advisories - Wed, 2020-08-26 14:48

A vulnerability in the web-based management interface of Cisco Integrated Management Controller (IMC) could allow an authenticated, remote attacker to inject arbitrary commands and obtain root privileges.

The vulnerability is due to insufficient validation of user-supplied input in the Certificate Signing Request (CSR) function of the web-based management interface. An attacker could exploit this vulnerability by submitting a crafted CSR in the web-based management interface. A successful exploit could allow an attacker with administrator privileges to execute arbitrary commands on the device with full root privileges.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190821-imc-cmdinject-1896


Security Impact Rating: High
CVE: CVE-2019-1896
Categories: Security Alerts

AA20-239A: FASTCash 2.0: North Korea's BeagleBoyz Robbing Banks

US-CERT - Wed, 2020-08-26 07:17
Original release date: August 26, 2020
Summary

This Alert uses the MITRE Adversarial Tactics, Techniques, and Common Knowledge (ATT&CK®) framework. See the ATT&CK for Enterprise framework for all referenced threat actor techniques.

This joint advisory is the result of analytic efforts among the Cybersecurity and Infrastructure Security Agency (CISA), the Department of the Treasury (Treasury), the Federal Bureau of Investigation (FBI) and U.S. Cyber Command (USCYBERCOM). Working with U.S. government partners, CISA, Treasury, FBI, and USCYBERCOM identified malware and indicators of compromise (IOCs) used by the North Korean government in an automated teller machine (ATM) cash-out scheme—referred to by the U.S. Government as “FASTCash 2.0: North Korea's BeagleBoyz Robbing Banks.”

CISA, Treasury, FBI, and USCYBERCOM highlight the cyber threat posed by North Korea—formally known as the Democratic People’s Republic of Korea (DPRK)—and provide recommended steps to mitigate the threat.

Refer to the following Malware Analysis Reports for associated IOCs: CROWDEDFLOUNDER, ECCENTRICBANDWAGON, ELECTRICFISH, FASTCash for Windows, HOPLIGHT, and VIVACIOUSGIFT.

Click here for a PDF version of this report.

!!!WARNING!!! Since February 2020, North Korea has resumed targeting banks in multiple countries to initiate fraudulent international money transfers and ATM cash outs. The recent resurgence follows a lull in bank targeting since late 2019. This advisory provides an overview of North Korea’s extensive, global cyber-enabled bank robbery scheme, a short profile of the group responsible for this activity, in-depth technical analysis, and detection and mitigation recommendations to counter this ongoing threat to the Financial Services sector. !!!WARNING!!!

 

Technical Details

North Korea's intelligence apparatus controls a hacking team dedicated to robbing banks through remote internet access. To differentiate methods from other North Korean malicious cyber activity, the U.S. Government refers to this team as BeagleBoyz, who represent a subset of HIDDEN COBRA activity. The BeagleBoyz overlap to varying degrees with groups tracked by the cybersecurity industry as Lazarus, Advanced Persistent Threat 38 (APT38), Bluenoroff, and Stardust Chollima and are responsible for the FASTCash ATM cash outs reported in October 2018, fraudulent abuse of compromised bank-operated SWIFT system endpoints since at least 2015, and lucrative cryptocurrency thefts. This illicit behavior has been identified by the United Nations (UN) DPRK Panel of Experts as evasion of UN Security Council resolutions, as it generates substantial revenue for North Korea. North Korea can use these funds for its UN-prohibited nuclear weapons and ballistic missile programs. Additionally, this activity poses significant operational risk to the Financial Services sector and erodes the integrity of the financial system.

The BeagleBoyz’s bank robberies pose severe operational risk for individual firms beyond reputational harm and financial loss from theft and recovery costs. The BeagleBoyz have attempted to steal nearly $2 billion since at least 2015, according to public estimates. Equally concerning, these malicious actors have manipulated and, at times, rendered inoperable, critical computer systems at banks and other financial institutions.  

  • In 2018, a bank in Africa could not resume normal ATM or point of sale services for its customers for almost two months following an attempted FASTCash incident.
  • The BeagleBoyz often put destructive anti-forensic tools onto computer networks of victim institutions. Additionally, in 2018, they deployed wiper malware against a bank in Chile that crashed thousands of computers and servers to distract from efforts to send fraudulent messages from the bank’s compromised SWIFT terminal.

North Korea’s widespread international bank robbery scheme that exploits critical banking systems may erode confidence in those systems and presents risks to financial institutions across the world. Any BeagleBoyz robbery directed at one bank implicates many other financial services firms in both the theft and the flow of illicit funds back to North Korea. BeagleBoyz activity fits a known North Korean pattern of abusing the international financial system for profit.

  • Fraudulent ATM cash outs have affected upwards of 30 countries in a single incident. The conspirators have withdrawn cash from ATM machines operated by various unwitting banks in multiple countries, including in the United States.
  • The BeagleBoyz also use unwitting banks, including banks in the United States, for their SWIFT fraud scheme. These banks are custodians of accounts belonging to victim banks or unknowingly serve as a pass-through for the fraud. Most infamously, the BeagleBoyz stole $81 million from the Bank of Bangladesh in 2016. The Federal Reserve Bank of New York stopped the remainder of this attempted $1 billion theft after detecting anomalies in the transfer instructions they had received.

FASTCash Update

North Korea’s BeagleBoyz are responsible for the sophisticated cyber-enabled ATM cash-out campaigns identified publicly as “FASTCash” in October 2018. Since 2016, the BeagleBoyz have perpetrated the FASTCash scheme, targeting banks’ retail payment system infrastructure (i.e., switch application servers processing International Standards Organization [ISO] 8583 messages, which is the standard for financial transaction messaging).

Since the publication of the in October 2018, there have been two particularly significant developments in the campaign: (1) the capability to conduct the FASTCash scheme against banks hosting their switch applications on Windows servers, and (2) an expansion of the FASTCash campaign to target interbank payment processors.

  • In October 2018, the U.S. Government identified malware used in the FASTCash scheme that has the capability to manipulate AIX servers running a bank's switch application to intercept financial request messages and reply with fraudulent, but legitimate-looking, affirmative response messages to enable extensive ATM cash outs. The U.S. Government has since identified functionally equivalent malware for the Windows operating system. Please see the Technical Analysis section below for more information about the ISO 8583 malware for Windows.
  • The BeagleBoyz initially targeted switch applications at individual banks with FASTCash malware but, more recently, have targeted at least two regional interbank payment processors. This suggests the BeagleBoyz are exploring upstream opportunities in the payments ecosystem.

For more information about FASTCash, please see https://www.us-cert.gov/ncas/alerts/TA18-275A.

BEAGLEBOYZ Profile

The BeagleBoyz, an element of the North Korean government’s Reconnaissance General Bureau, have likely been active since at least 2014. As opposed to typical cybercrime, the group likely conducts well-planned, disciplined, and methodical cyber operations more akin to careful espionage activities. Their malicious cyber operations have netted hundreds of millions of U.S. dollars and are likely a major source of funding for the North Korean regime. The group has always used a calculated approach, which allows them to sharpen their tactics, techniques, and procedures while evading detection. Over time, their operations have become increasingly complex and destructive. The tools and implants employed by this group are consistently complex and demonstrate a strong focus on effectiveness and operational security.

Community Identifiers

The BeagleBoyz overlap to varying degrees with groups tracked by the cybersecurity industry as: APT38 (FireEye), Bluenoroff (Kaspersky), Lazarus Group (ESTSecurity), and Stardust Chollima (CrowdStrike).

Targeted Nations

The BeagleBoyz likely have targeted financial institutions in the following nations from 2015 through 2020: Argentina, Brazil, Bangladesh, Bosnia and Herzegovina, Bulgaria, Chile, Costa Rica, Ecuador, Ghana, India, Indonesia, Japan, Jordan, Kenya, Kuwait, Malaysia, Malta, Mexico, Mozambique, Nepal, Nicaragua, Nigeria, Pakistan, Panama, Peru, Philippines, Singapore, South Africa, South Korea, Spain, Taiwan, Tanzania, Togo, Turkey, Uganda, Uruguay, Vietnam, Zambia (figure 1).

Figure 1: Nations probably targeted by BeagleBoyz since 2015

Anatomy of a BeagleBoyz Bank Heist

Figure 2 provides a graphical depiction of a BeagleBoyz bank heist. The next section describes in detail the end-to-end actions the BeagleBoyz take to rob financial institutions with a malicious cyber operation.

Figure 2: BeagleBoyz Bank Heist overview

Technical Analysis

The BeagleBoyz use a variety of tools and techniques to gain access to a financial institution’s network, learn the topology to discover key systems, and monetize their access. The technical analysis below represents an amalgamation of multiple known incidents, rather than details of a single operation. These findings are presented to highlight the group’s ability to tailor their techniques to different targets and to adapt their methods over time. Consequently, there is a need for layered mitigations to effectively defend against this activity, as relying solely on network signature detection will not sufficiently protect against North Korea’s BeagleBoyz.

Initial Access

The BeagleBoyz have used a variety of techniques, such as spearphishing and watering holes, to enable initial access into targeted financial institutions. Towards the end of 2018 through 2019 and in early 2020, the BeagleBoyz demonstrated the use of social engineering tactics by carrying out job-application themed phishing attacks using the following publicly available malicious files.

MD5: b484b0dff093f358897486b58266d069
MD5: f34b72471a205c4eee5221ab9a349c55
MD5: 4c26b2d0e5cd3bfe0a3d07c4b85909a4
MD5: 52ec074d8cb8243976963674dd40ffe7
MD5: d1d779314250fab284fd348888c2f955
MD5: 41fd85ff44107e4604db2f00e911a766
MD5: cf733e719e9677ebfbc84a3ab08dd0dc
MD5: 01d397df2a1cf1d4c8e3615b7064856c

The BeagleBoyz may also be working with or contracting out to criminal hacking groups, like TA505, for initial access development. The third party typically uses commodity malware to establish initial access on a victim’s network and then turns over the access to the BeagleBoyz for follow-on exploitation, which may not occur until months later.

The BeagleBoyz have also used the following techniques to gain an initial foothold on a targeted computer network (Initial Access [TA0001]).

  • Email an attachment with malware to a specific individual, company, or industry (Phishing: Spearphishing Attachment [T1566.001])
  • Compromise a website visited by users in specific communities, industries, or regions (Drive-by Compromise [T1189])
  • Exploit a weakness (a bug, glitch, or design vulnerability) in an internet-facing computer system (such as a database or web server) (Exploit Public Facing Application [T1190])
  • Steal the credentials of a specific user or service account to bypass access controls and gain increased privileges (Valid Accounts [T1078])
  • Breach organizations that have access to the intended victim’s organization and exploit their trusted relationship (Trusted Relationship [T1199])
  • Use remote services to initially access and persist within a victim’s network (External Remote Services [T1133])
Execution

The BeagleBoyz selectively exploit victim computer systems after initially compromising a computer connected to a financial institution’s corporate network. After gaining initial access to a financial institution’s corporate network, the BeagleBoyz are selective in which victim systems they further exploit. The BeagleBoyz use a variety of techniques to run their code on local and remote victim systems [Execution [TA0002]).

  • Use command-line interfaces to interact with systems and execute other software (Command and Scripting Interpreter [T1059])
  • Use scripts (e.g., VBScript and PowerShell) to speed up operational tasks, reduce the time required to gain access to critical resources, and bypass process monitoring mechanisms by directly interacting with the operating system (OS) at an Application Programming Interface (API) level instead of calling other programs (Command and Scripting Interpreter: PowerShell [T1059.001], Command and Scripting Interpreter: Visual Basic [T1059.005])
  • Rely upon specific user actions, such as opening a malicious email attachment (User Execution [T1204])
  • Exploit software vulnerabilities to execute code on a system (Exploitation for Client Execution [T1203])
  • Create new services or modify existing services to execute executables, commands, or scripts (System Services: Service Execution [T1569.002])
  • Employ the Windows module loader to load Dynamic Link Libraries (DLLs) from arbitrary local paths or arbitrary Universal Naming Convention (UNC) network paths and execute arbitrary code on a system (Shared Modules [T1129])
  • Use the Windows API to execute arbitrary code on the victim's system (Native API [T1106])
  • Use a system's graphical user interface (GUI) to search for information and execute files (Remote Services [T1021])
  • Use the Task Scheduler to run programs at system startup or on a scheduled basis for persistence, conduct remote execution for lateral movement, gain SYSTEM privileges for privilege escalation, or run a process under the context of a specified account (Scheduled Task/Job [T1053])
  • Abuse compiled Hypertext Markup Language (HTML) files (.chm), commonly distributed as part of the Microsoft HTML Help system, to conceal malicious code (Signed Binary Proxy Execution: Compiled HTML File [T1218.001])
  • Abuse Windows rundll32.exe to execute binaries, scripts, and Control Panel Item files (.CPL) and execute code via proxy to avoid triggering security tools (Signed Binary Proxy Execution: Rundl32 [T1218.001])
  • Exploit cron in Linux and launchd in macOS systems to create pre-scheduled and periodic background jobs (Scheduled Task/Job: Cron [T1053.003], Scheduled Task/Job: Launchd [T1053.004])
Persistence

The BeagleBoyz use many techniques to maintain access on compromised networks through system restarts, changed credentials, and other interruptions that could affect their access (Persistence [TA0003]).

  • Add an entry to the “run keys” in the Registry or an executable to the startup folder to execute malware as the user logs in under the context of the user’s associated permissions levels (Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder [T1547.001])
  • Install a new service that can be configured to execute at startup using utilities to interact with services or by directly modifying the Registry (Create or Modify System Process: Windows Service [T1543.003])
  • Compromise an openly accessible web server with a web script (known as web shell) to use the web server as a gateway into a network and to serve as redundant access or persistence mechanism (Server Software Component: Web Shell [T1505.003])
  • Manipulate accounts (e.g., modifying permissions, modifying credentials, adding or changing permission groups, modifying account settings, or modifying how authentication is performed) to maintain access to credentials and certain permission levels within an environment (Account Manipulation [T1098])
  • Steal the credentials of a specific user or service account to bypass access controls and retain access to remote systems and externally available services (Valid Accounts [T1078])
  • Use the Task Scheduler to run programs at system startup or on a scheduled basis for persistence, conduct remote execution for lateral movement, gain SYSTEM privileges for privilege escalation, or run a process under the context of a specified account (Scheduled Task/Job [T1053])
  • Abuse the Windows DLLs search order and programs that ambiguously specify DLLs to gain privilege escalation and persistence (Hijack Execution Flow: DLL Search Order Hijacking [T1056.004])
  • Exploit hooking to load and execute malicious code within the context of another process to mask the execution, allow access to the process’s memory, and, possibly, gain elevated privileges (Input Capture: Credential API Hooking [T1574.001])
  • Use remote services to persist within a victim’s network (External Remote Services [T1133])
Privilege Escalation

The BeagleBoyz often seek access to financial institutions’ systems that have tiered user and system accounts with customized privileges. The BeagleBoyz must overcome these restrictions to access necessary systems, monitor normal user behavior, and install and execute additional malicious tools. To do so, the BeagleBoyz have used the following techniques to gain higher-level permissions on a system or network (Privilege Escalation [TA0004]).

  • Inject code into processes to evade process-based defenses and elevate privileges (Process Injection [T1055])
  • Install a new service that can be configured to execute at startup using utilities to interact with services or by directly modifying the Registry (Create or Modify System Process: Windows Service [T1543.003])
  • Compromise an openly accessible web server with web shell to use the web server as a gateway into a network (Server Software Component: Web Shell [T1505.003])
  • Use the Task Scheduler to run programs at system startup or on a scheduled basis for persistence, conduct remote execution as part of lateral movement, gain SYSTEM privileges for privilege escalation, or run a process under the context of a specified account (Scheduled Task/Job [T1053])
  • Steal the credentials of a specific user or service account to bypass access controls and grant increased privileges (Valid Accounts [T1078])
  • Exploit hooking to load and execute malicious code within the context of another process to mask the execution, allow access to the process’s memory, and, possibly, gain elevated privileges (Input Capture: Credential API Hooking [T1574.001])
  • Perform Sudo (sometimes referred to as “super user do”) caching or use the Soudoers file to elevate privileges in Linux and macOS systems (Abuse Elevation Control Mechanism: Sudo and Sudo Caching [T1548.003])
  • Execute malicious payloads by hijacking the search order used to load DLLs (Hijack Execution Flow: DLL Search Order Hijacking [T1574.001])
Defense Evasion

Throughout their exploitation of a financial institution’s computer network, the BeagleBoyz have used different techniques to avoid detection by OS security features, system and network security software, and system audits (Defense Evasion [TA0005]).

  • Exploit code signing certificates to masquerade malware and tools as legitimate binaries and bypass security policies that allow only signed binaries to execute on a system (Subvert Trust Controls Signing [T1553.002])
  • Remove malware, tools, or other non-native files dropped or created throughout an intrusion to reduce their footprint or as part of the post-intrusion cleanup process (Indicator Removal on Host: File Deletion [T1070.004])
  • Inject code into processes to evade process-based defenses (Process Injection [T1055])
  • Use scripts (such as VBScript and PowerShell) to bypass process monitoring mechanisms by directly interacting with the OS at an API level instead of calling other programs (Command and Scripting Interpreter: PowerShell [T1059.001], Command and Scripting Interpreter: Visual Basic [T1059.005])
  • Attempt to make an executable or file challenging to discover or analyze by encrypting, encoding, or obfuscating its contents on the system or in transit (Obfuscated Files or Information [T1027])
  • Use external previously compromised web services to relay commands to a victim system (Web Service [T1102])
  • Use software packing to change the file signature, bypass signature-based detection, and decompress the executable code in memory (Unsecured Credentials: Private Keys [T1552.004])
  • Use obfuscated files or information to hide intrusion artifacts (Deobfuscate/Decode Files or Information [T1140])
  • Modify the data timestamps (the modify, access, create, and change times fields) to mimic files that are in the same folder, making them appear inconspicuous to forensic analysts or file analysis tools (Indicator Removal on Host: Remove Timestamp [T1070.006])
  • Abuse Windows utilities to implement arbitrary execution commands and subvert detection and mitigation controls (such as Group Policy) that limit or prevent the usage of cmd.exe or file extensions commonly associated with malicious payloads (Indirect Command Execution [T1202])
  • Use various methods to prevent their commands from appearing in logs and clear command history to remove activity traces (Indicator Removal on Host: Clear Command History [T1070.003])
  • Disable security tools to avoid possible detection of tools and events (Impair Defenses: Disable or Modify Tools [T1562.001])
  • Steal the credentials of a specific user or service account to bypass access controls and grant increased privileges (Valid Accounts [T1078])
  • Delete or alter generated artifacts on a host system, including logs and potentially captured files, to remove traces of activity (Indicator Removal on Host: File Deletion [T1070.004])
  • Abuse compiled HTML files (.chm), commonly distributed as part of the Microsoft HTML Help system, to conceal malicious code (Signed Binary Proxy Execution: Compiled HTML File [T1218.001])
  • Prepend a space to all their terminal commands to operate without leaving traces in the HISTCONTROL environment, which is configured to ignore commands that start with a space (Impair Defenses: HISTCONTROL [T1562.003])
  • Modify malware so it has a different signature and re-use it in cases when the group determines it was quarantined (Obfuscated Files or Information: Indicator Removal from Tools [T1027.005])
  • Attempt to block indicators or events typically captured by sensors from being gathered and analyzed (Impair Defenses: Indicator Blocking [T1562.006])
  • Use the Windows DLLs search order and programs that ambiguously specify DLLs to gain privilege escalation and persistence (Hijack Execution Flow: DLL Search Order Hijacking [T1574.001])
  • Manipulate or abuse the attributes or location of an executable (masquerading) to better blend in with the environment and increase the chances of deceiving a security analyst or product (Masquerading [T1036])
  • Exploit rootkits to hide programs, files, network connections, services, drivers, and other system components (Rootkit [T1014])
  • Abuse the Windows rundll32.exe to execute binaries, scripts, and .CPL files, and execute code via proxy to avoid triggering security tools (Signed Binary Proxy Execution: Rundl32 [T1218.001])
Credential Access

The BeagleBoyz may use malware like ECCENTRICBANDWAGON to log key strokes and take screen captures. The U.S. Government has identified some ECCENTRICBANDWAGON samples that have the ability to RC4 encrypt logged data, but the tool has no network functionality. The implant uses specific formatting for logged data and saves the file locally; another tool obtains the logged data. The implant also contains no mechanism for persistence or self-loading and expects a specific configuration file to be present on the system. A full technical report for ECCENTRICBANDWAGON is available at https://us-cert.cisa.gov/northkorea.

The BeagleBoyz may not always need to use custom keyloggers like ECCENTRICBANDWAGON or other tools to obtain credentials from a compromised system. Depending on the victim’s environment, the BeagleBoyz have used the following techniques to steal credentials (Credential Access [TA0006]).

  • Capture user input, such as keylogging (the most prevalent type of input capture), to obtain credentials for valid accounts and information collection (Input Capture [T1056])
  • Obtain account login and password information, generally in the form of a hash or a clear text password, from the operating system and software (OS Credential Dumping [T1056])
  • Gather private keys from compromised systems to authenticate to remote services or decrypt other collected files (Unsecured Credentials: Private Keys [T1552.004])
  • Manipulate default, domain, local, and cloud accounts to maintain access to credentials and certain permission levels within an environment (Account Manipulation [T1098])
  • Abuse hooking to load and execute malicious code within the context of another process to mask the execution, allow access to the process's memory, and, possibly, gain elevated privileges (Input Capture: Credential API Hooking [T1056.004])
  • Use brute force techniques to attempt account access when passwords are unknown or when password hashes are unavailable (Brute Force [T1110])
Discovery

Once inside a financial institution’s network, the BeagleBoyz appear to seek two specific systems—the SWIFT terminal and the server hosting the institution’s payment switch application. As they progress through a network, they learn about the systems they have accessed in order to map the network and gain access to the two goal systems. To do so, the BeagleBoyz have used the following techniques to gain knowledge about the systems and internal network (Discovery [TA0007]).

  • Attempt to get detailed information about the operating system and hardware, such as version, patches, hotfixes, service packs, and architecture (System Information Discovery [T1082])
  • Enumerate files and directories or search in specific locations of a host or network share for particular information within a file system (File and Directory Discovery [T1083])
  • Get a list of security software, configurations, defensive tools, and sensors installed on the system (Software Discovery: Security Software Discovery [T1518.001])
  • Procure information about running processes on a system to understand standard software running on network systems (Process Discovery [T1057])
  • Identify primary users, currently logged in users, sets of users that commonly use a system, or active or inactive users (System Owner/User Discovery [T1033])
  • Enumerate browser bookmarks to learn more about compromised hosts, reveal personal information about users, and expose details about internal network resources (Browser Bookmark Discovery [T1217])
  • Look for information on network configuration and system settings on compromised systems, or perform remote system discovery (System Network Configuration Discovery [T1016])
  • Interact with the Windows Registry to gather information about the system, configuration, and installed software (Query Registry [T1012])
  • Get a list of open application windows to learn how the system is used or give context to data collected (Application Window Discovery [T1010])
  • Attempt to get a listing of local system or domain accounts in the compromised system (Account Discovery [T1087])
  • Obtain a list of network connections to and from the compromised system or remote system by querying for information over the network (System Network Connections Discovery [T1049])
Lateral Movement

To access a compromised financial institution’s SWIFT terminal and the server hosting the institution’s payment switch application, the BeagleBoyz leverage harvested credentials and take advantage of the accessibility of these critical systems from other systems in the institution’s corporate network. Specifically, the BeagleBoyz have been known to create firewall exemptions on specific ports, including ports 443, 6443, 8443, and 9443. Depending on the configuration of compromised systems and the security environment of the victim’s computer network, the BeagleBoyz have used the following techniques to enter and control remote systems on a compromised network (Lateral Movement [TA0008]).

  • Copy files from one system to another to stage adversary tools or other files throughout an operation (Ingress Tool Transfer [T1105])
  • Use Remote Desktop Protocol (RDP) to log into an interactive session with a system desktop GUI on a remote system (Remote Services: Remote Desktop Protocol [T1021.001])
  • Employ hidden network shares, in conjunction with administrator-level valid accounts, to remotely access a networked system over Server Message Block (SMB) in order to interact with systems using remote procedure calls (RPCs), transfer files, and run transferred binaries through remote execution (Remote Services: SMB/Windows Admin Shares [T1021.002])
  • Exploit valid accounts to log into a service specifically designed to accept remote connections and perform actions as the logged-on user (Remote Services [T1021])
Collection

Depending on various environmental attributes the BeagleBoyz encounter during their exploitation, they may deploy a variety of reconnaissance tools or use commonly available administrative tools for malicious purposes.

The BeagleBoyz, like other sophisticated cyber actors, also appear to use resident, legitimate administrative tools for reconnaissance purposes when they are available; this is commonly known as “living off the land.” PowerShell appears to be a popular otherwise-legitimate tool the BeagleBoyz favor for reconnaissance activities. For example, the BeagleBoyz often use publicly available code from PowerShell Empire for malicious purposes.

The BeagleBoyz have used the following techniques to gather information from exploited systems (Collection [TA0009]).

  • Use automated methods, such as scripts, for collecting data (Automated Collection [T1119])
  • Capture user input to obtain credentials and collect information (Input Capture [T1056])
  • Collect local systems data from a compromised system (Data from Local System [T1005])
  • Take screen captures of the desktop (Screen Capture [T1113])
  • Collect data stored in the Windows clipboard from users (Clipboard Data [T1115])
Command and Control

The BeagleBoyz likely change tools—such as CROWDEDFLOUNDER and HOPLIGHT—over time to maintain remote access to financial institution networks and to interact with those systems.

Analysis of the following CROWDEDFLOUNDER samples was first released in October 2018 as part of the FASTCash campaign.

MD5 hash: 5cfa1c2cb430bec721063e3e2d144feb
MD5 hash: 4f67f3e4a7509af1b2b1c6180a03b3e4

The BeagleBoyz have used CROWDEDFLOUNDER as a remote access trojan (RAT) since at least 2018. The implant is designed to operate on Microsoft Windows hosts and can upload and download files, launch a remote command shell, inject into victim processes, obtain user and host information, and securely delete files. The implant may be packed with Themida to degrade or prevent effective reverse engineering or evade detection on a Windows host. It can be set to act in beacon or listening modes, depending on command line arguments or configuration specifications. The implant obfuscates network communications using a simple encoding algorithm. The listening mode of CROWDEDFLOUNDER facilitates proxies like ELECTRICFISH (discussed below) with tunneling traffic in a victim’s network.

More recently, the U.S. Government has found HOPLIGHT malware on victim systems, suggesting the BeagleBoyz are using HOPLIGHT for similar purposes. HOPLIGHT has the same basic RAT functionality as the CROWDEDFLOUNDER implant. In addition, HOPLIGHT has the capability to create fraudulent Transport Layer Security (TLS) sessions to obfuscate command and control (C2) connections, making detection and tracking of the malware’s communications difficult.

Full technical reports for CROWDEDFLOUNDER and HOPLIGHT are available at https://us-cert.cisa.gov/northkorea.

The BeagleBoyz use network proxy tunneling tools—including VIVACIOUSGIFT and ELECTRICFISH—to tunnel communications from non-internet facing systems like an ATM switch application server or a SWIFT terminal to internet-facing systems. The BeagleBoyz use these network proxy tunneling tools, likely placed at or near a victim’s network boundary, to tunnel other protocols such as RDP and Secure Shell or other implant traffic out from the internal network.

It appears that as the BeagleBoyz change proxy tools, there is some overlap between their use of older and newer malware. For example, the BeagleBoyz appear to have begun using ELECTRICFISH as they wound down use of VIVACIOUSGIFT. There has been a noticeable decline in ELECTRICFISH use following the U.S. Government’s disclosure of it in May 2019.

Full technical reports for VIVACIOUSGIFT and ELECTRICFISH are available at https://us-cert.cisa.gov/northkorea.

In addition to these tools, the BeagleBoyz have used the following techniques to communicate with financial institution victim systems under their control (Command and Control [TA0011]).

  • Employ known encryption algorithms to conceal C2 traffic (Encrypted Channel [T1573])
  • Communicate over commonly used standard application layer protocols and ports to avoid detection or detailed inspection and to blend with existing traffic (Application Layer Protocol [T1071])
  • Encode C2 information using standard data encoding systems such as the American Standard Code for Information Interchange (ASCII), Unicode, Base64, Multipurpose Internet Mail Extensions, and 8-bit Unicode Transformation Format systems or other binary-to-text and character encoding systems (Data Encoding: Standard Encoding [T1132.001])
  • Copy files between systems to stage adversary tools or other files (Ingress Transfer Tool [T1105])
  • Use external previously compromised web services to relay commands to victim systems (Web Service [T1102])
  • Employ a custom C2 protocol that mimics well-known protocols, or develop custom protocols (including raw sockets) to supplement protocols provided by another standard network stack (Non-Application Layer Protocol [T1095])
  • Obfuscate C2 communications (but not necessarily encrypt them) to hide commands and make the content less conspicuous and more challenging to discover or decipher (Data Obfuscation [T1101])
  • Employ connection proxies to direct network traffic between systems, act as an intermediary for network communications to a C2 server, or avoid direct connections to its infrastructure (Proxy [T1090])
  • Exploit legitimate desktop support and remote access software to establish an interactive C2 channel to target systems within networks (Remote Access Software [T1219])

Cryptocurrency Exchange Heists

In addition to robbing traditional financial institutions, the BeagleBoyz target cryptocurrency exchanges to steal large amounts of cryptocurrency, sometimes valued at hundreds of millions of dollars per incident. Cryptocurrency offers the BeagleBoyz an irreversible method of theft that can be converted into fiat currency because the permanent nature of cryptocurrency transfers do not allow for claw-back mechanisms. Working with U.S. Government partners, CISA, Treasury, FBI, and USCYBERCOM identified COPPERHEDGE as the tool of choice for the BeagleBoyz to exploit cryptocurrency exchanges. COPPERHEDGE is a full-featured remote access tool capable of running arbitrary commands, performing system reconnaissance, and exfiltrating data. Full technical analysis of COPPERHEDGE is available at https://us-cert.cisa.gov/northkorea.

Exfiltration

During a cyber operation, the BeagleBoyz need to exfiltrate a variety of data from compromised systems. In addition to the C2 tools noted that have built-in exfiltration features, such as CROWDEDFLOUNDER and HOPLIGHT, the BeagleBoyz use the following techniques to steal data from a network (Exfiltration [TA0010]).

  • Compress and encrypt collected data before exfiltration to minimize the amount of data sent over the web and make it portable, less conspicuous, and less detectable (Archive Collected Data [T1560])
  • Steal collected data via scripts (although this may require other exfiltration techniques) (Automated Exfiltration [T1020])
  • Encode data using the same protocol as the C2 channel and exfiltrate it over the C2 channel (Exfiltration Over C2 Channel [T1041])
Impact

The U.S. Government has observed the BeagleBoyz successfully monetize illicit access to financial institutions’ SWIFT terminals to enable wire fraud and gain access to the institutions’ payment switch application servers, which allowed fraudulent ATM cash outs. After gaining access to either one or both of these operationally critical systems, the BeagleBoyz monitor the systems to learn about their configurations and legitimate use patterns, and then they deploy bespoke tools to facilitate illicit monetization.

The cybersecurity community and Financial Services sector have released substantial information on the BeagleBoyz manipulation of compromised SWIFT terminals, describing their ability to monitor these systems, send fraudulent messages, and attempt to hide the fraudulent activity from detection. The discussion below focuses on the custom tools used to manipulate payment switch applications for ATM cash outs.

The BeagleBoyz use FASTCash malware to intercept financial request messages and reply with fraudulent but legitimate-looking affirmative response messages in the ISO 8583 format. The BeagleBoyz have functionally equivalent FASTCash malware for both UNIX and Windows that they deploy depending on the operating system running on the server hosting the bank’s payment switch application.

FASTCash for UNIX is composed of AIX executable files designed to inject code and libraries into a currently running process. One AIX executable provides export functions, which allows an application to manipulate transactions on financial systems using the ISO 8583 international standard for financial transaction card-originated interchange messaging. The injected executables interpret financial request messages and construct fraudulent financial response messages. For more details on FASTCash for UNIX malware, please see the FASTCash report at https://www.us-cert.gov/ncas/alerts/TA18-275A.

The BeagleBoyz use FASTCash for Windows to manipulate transactions processed by a switch application running on a Windows box. FASTCash for Windows is also specific to the ISO 8583 message format. The BeagleBoyz appear to have modified publicly available source code to write parts of the tool, likely to speed development. The malware contains code probably taken from open-source repositories on the internet to create hashmaps and hook functions and to parse ISO 8583 messages.

FASTCash for Windows injects itself into software running on a Windows platform. The malware then takes control of the software’s network send and receive functions, allowing it to manipulate ISO 8583 messages. The U.S. Government has identified two variants of FASTCash for Windows. One variant supports ASCII encoding. The BeagleBoyz appear to have modified the second variant’s message parsing code to support Extended Binary Coded Decimal Interchange Code (EBCIDC) encoding. Both ASCII and EBCDIC are character encoding formats.  

FASTCash for Windows malware uses code from github.com/petewarden/c_hashmap for hashmaps, code from Microsoft's Detours Library at github.com/Microsoft/Detours for hooking, and code from to parse ISO 8583 messages.

The malware hooks onto the send and receive function of the switch application so that it can process inbound request messages as they are received. FASTCash for Windows inspects the inbound message, probably looking for specific account numbers. If the account number matches an expected number, the malware constructs a fraudulent response message. If the account number does not match an expected number, the malware allows the request to pass through normally. If the malware constructs a fraudulent response message, it then sends it back to the acquirer without any further processing by the switch application, leaving the issuer without any awareness of the fraudulent transaction.

Full technical reports for FASTCash and FASTCash for Windows malware are available at https://us-cert.cisa.gov/northkorea.

The BeagleBoyz have used the following techniques to manipulate business and operational processes for monetary or destructive purposes (Impact [TA0040]).

  • Corrupt or wipe data storage, data structures, and Master Boot Records (MBR) to interrupt network availability, services, and resources (Disk Wipe: Disk Structure Wipe [T1561.002], Data Destruction [T1485])
  • Encrypt data on target systems and withhold access to the decryption key until a ransom is paid, or render data permanently inaccessible if the ransom is not paid (Data Encrypted for Impact [T1486])
  • Stop, disable, or render services unavailable on a system to damage the environment or inhibit incident response (Service Stop [T1489])
  • Insert, delete, or modify data at rest, in transit, or in use to manipulate outcomes, hide activity, and affect the business process, organizational understanding, and decision-making (Data Manipulation: Stored Data Manipulation [T1565.001], Data Manipulation: Transmitted Data Manipulation [T1565.002], Data Manipulation: Runtime Data Manipulation [T1565.003])
Mitigations
  • Contact law enforcement, CISA, or Treasury immediately regarding any identified activity related to BeagleBoyz. (Refer to the Contact Information section.)
  • Incorporate IOCs identified in CISA’s Malware Analysis Reports on https://us-cert.cisa.gov/northkorea into intrusion detection systems and security alert systems to enable active blocking or reporting of suspected malicious activity.
Recommendations for all Financial Institutions Recommendations for Institutions with Retail Payment Systems

Require chip and personal identification number (PIN) cryptogram validation.

  • Implement chip and PIN requirements for debit cards.
  • Validate card-generated authorization request cryptograms.
  • Use issuer-generated authorization response cryptograms for response messages.
  • Require card-generated authorization response cryptogram validation to verify legitimate response messages.

Isolate payment system infrastructure.

  • Require multi-factor authentication for any user to access the switch application server.
  • Confirm perimeter security controls prevent internet hosts from accessing the private network infrastructure servicing your payment switch application server.
  • Confirm perimeter security controls prevent all hosts outside of authorized endpoints from accessing your system, especially if your payment switch application server is internet accessible.

Logically segregate your operating environment.

  • Use firewalls to divide your operating environment into enclaves.
  • Use access control lists to permit/deny specific traffic from flowing between those enclaves.
  • Give special considerations to segregating enclaves holding sensitive information (e.g., card management systems) from enclaves requiring internet connectivity (e.g., email).

Encrypt data in transit.

  • Secure all links to payment system engines with a certificate-based mechanism, such as Mutual Transport Layer Security, for all external and internal traffic external.
  • Limit the number of certificates that can be used on the production server and restrict access to those certificates.

Monitor for anomalous behavior as part of layered security.

  • Configure the switch application server to log transactions and routinely audit transaction and system logs.
  • Develop a baseline of expected software, users, and logons and monitor switch application servers for unusual software installations, updates, account changes, or other activities outside of expected behavior.
  • Develop a baseline of expected transaction participants, amounts, frequency, and timing. Monitor and flag anomalous transactions for suspected fraudulent activity.
Recommendations for Organizations with ATM or Point of Sale Devices

Validate issuer responses to financial request messages.

  • Implement chip and PIN requirements for debit cards.
  • Require and verify message authentication codes on issuer financial request response messages.
  • Perform authorization response cryptogram validation for chip and PIN transactions.
Recommendations for All Organizations

Users and administrators should use the following best practices to strengthen the security posture of their organization’s systems:

  • Maintain up-to-date antivirus signatures and engines.
  • Keep operating system patches up to date.
  • Disable file and printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
  • Restrict users’ ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators’ group unless required.
  • Enforce a strong password policy and require regular password changes.
  • Exercise caution when opening email attachments even if the attachment is expected and the sender appears to be known.
  • Enable a personal firewall on agency workstations and configure it to deny unsolicited connection requests.
  • Disable unnecessary services on agency workstations and servers.
  • Scan for and remove suspicious email attachments; ensure the scanned attachment is its “true file type” (i.e., the extension matches the file header).
  • Monitor users' web browsing habits; restrict access to sites with unfavorable content.
  • Exercise caution when using removable media (e.g., USB thumb drives, external drives, CDs).
  • Scan all software downloaded from the internet before executing.
  • Maintain situational awareness of the latest threats.
  • Implement appropriate access control lists.

Additional information on malware incident prevention and handling can be found in National Institute of Standards and Technology Special Publication 800-83, Guide to Malware Incident Prevention and Handling for Desktops and Laptops.

 

Contact Information

Recipients of this report are encouraged to contribute any additional information that they may have related to this threat.

For any questions related to this report or to report an intrusion and request resources for incident response or technical assistance, please contact:

DISCLAIMER   This information is provided "as is" for informational purposes only. The United States Government does not provide any warranties of any kind regarding this information. In no event shall the United States Government or its contractors or subcontractors be liable for any damages, including but not limited to, direct, indirect, special or consequential damages, arising out of, resulting from, or in any way connected with this information, whether or not based upon warranty, contract, tort, or otherwise, whether or not arising out of negligence, and whether or not injury was sustained from, or arose out of the results of, or reliance upon the information.

 

The United States Government does not endorse any commercial product or service, including any subjects of analysis. Any reference to specific commercial products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply their endorsement, recommendation, or favoring by the United States Government.

 

Revisions
  • August 26, 2020: Initial Version

This product is provided subject to this Notification and this Privacy & Use policy.

Categories: Security Alerts

Cisco Hyperflex HX-Series Software Weak Storage Vulnerability

Cisco Security Advisories - Wed, 2020-08-19 16:00

A vulnerability in the installation component of Cisco Hyperflex HX-Series Software could allow an authenticated, local attacker to retrieve the password that was configured at installation on an affected device.

The vulnerability exists because sensitive information is stored as clear text. An attacker could exploit this vulnerability by authenticating to an affected device and navigating to the directory that contains sensitive information. A successful exploit could allow the attacker to obtain sensitive information in clear text from the affected device.

There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-HYP-WSV-yT3j5hSB


Security Impact Rating: Medium
CVE: CVE-2020-3389
Categories: Security Alerts

Cisco Webex Meetings Desktop App for Windows Arbitrary File Overwrite Vulnerability

Cisco Security Advisories - Wed, 2020-08-19 16:00

A vulnerability in Cisco Webex Meetings Desktop App for Windows could allow an unauthenticated, remote attacker to overwrite arbitrary files on an end-user system.

The vulnerability is due to improper validation of URL parameters that are sent from a website to the affected application. An attacker could exploit this vulnerability by persuading a user to follow a URL to a website that is designed to submit crafted input to the affected application. A successful exploit could allow the attacker to overwrite arbitrary files on the affected system, possibly corrupting or deleting critical system files.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-desktop-app-OVSfpVMj


Security Impact Rating: Medium
CVE: CVE-2020-3440
Categories: Security Alerts

Cisco vWAAS for Cisco ENCS 5400-W Series and CSP 5000-W Series Default Credentials Vulnerability

Cisco Security Advisories - Wed, 2020-08-19 16:00

A vulnerability in Cisco Virtual Wide Area Application Services (vWAAS) with Cisco Enterprise NFV Infrastructure Software (NFVIS)-bundled images for Cisco ENCS 5400-W Series and CSP 5000-W Series appliances could allow an unauthenticated, remote attacker to log into the NFVIS CLI of an affected device by using accounts that have a default, static password.

The vulnerability exists because the affected software has user accounts with default, static passwords. An attacker with access to the NFVIS CLI of an affected device could exploit this vulnerability by logging into the CLI. A successful exploit could allow the attacker to access the NFVIS CLI with administrator privileges.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-waas-encsw-cspw-cred-hZzL29A7


Security Impact Rating: Critical
CVE: CVE-2020-3446
Categories: Security Alerts

Cisco Vision Dynamic Signage Director Directory Traversal Information Disclosure Vulnerability

Cisco Security Advisories - Wed, 2020-08-19 16:00

A vulnerability in the web-based management interface of Cisco Vision Dynamic Signage Director could allow an unauthenticated, remote attacker to view potentially sensitive information on an affected device.

The vulnerability is due to incorrect permissions within Apache configuration. An attacker could exploit this vulnerability by sending a crafted HTTP request to the web-based management interface. A successful exploit could allow the attacker to view potentially sensitive information on the affected device.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-vdsd-W7mnkwj7


Security Impact Rating: Medium
CVE: CVE-2020-3484
Categories: Security Alerts

Cisco Smart Software Manager On-Prem Privilege Escalation Vulnerability

Cisco Security Advisories - Wed, 2020-08-19 16:00

A vulnerability in Cisco Smart Software Manager On-Prem (SSM On-Prem) could allow an authenticated, remote attacker to elevate privileges and execute commands with higher privileges.

The vulnerability is due to insufficient authorization of the System Operator role capabilities. An attacker could exploit this vulnerability by logging in with the System Operator role, performing a series of actions, and then assuming a new higher privileged role. A successful exploit could allow the attacker to perform all actions associated with the privilege of the assumed role. If that role is an administrative role, the attacker would gain full access to the device.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-smart-priv-esca-nqwxXWBu


Security Impact Rating: High
CVE: CVE-2020-3443
Categories: Security Alerts

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