Security Alerts

AA20-183A: Defending Against Malicious Cyber Activity Originating from Tor

US-CERT - Wed, 2020-07-01 18:00
Original release date: July 1, 2020
Summary

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

This advisory—written by the Cybersecurity Security and Infrastructure Security Agency (CISA) with contributions from the Federal Bureau of Investigation (FBI)—highlights risks associated with Tor, along with technical details and recommendations for mitigation. Cyber threat actors can use Tor software and network infrastructure for anonymity and obfuscation purposes to clandestinely conduct malicious cyber operations.[1],[2],[3]

Tor (aka The Onion Router) is software that allows users to browse the web anonymously by encrypting and routing requests through multiple relay layers or nodes. This software is maintained by the Tor Project, a nonprofit organization that provides internet anonymity and anti-censorship tools. While Tor can be used to promote democracy and free, anonymous use of the internet, it also provides an avenue for malicious actors to conceal their activity because identity and point of origin cannot be determined for a Tor software user. Using the Onion Routing Protocol, Tor software obfuscates a user’s identity from anyone seeking to monitor online activity (e.g., nation states, surveillance organizations, information security tools). This is possible because the online activity of someone using Tor software appears to originate from the Internet Protocol (IP) address of a Tor exit node, as opposed to the IP address of the user’s computer.

CISA and the FBI recommend that organizations assess their individual risk of compromise via Tor and take appropriate mitigations to block or closely monitor inbound and outbound traffic from known Tor nodes.

Click here for a PDF version of this report.

Risk Evaluation

Malicious cyber actors use Tor to mask their identity when engaging in malicious cyber activity impacting the confidentiality, integrity, and availability of an organization’s information systems and data. Examples of this activity include performing reconnaissance, penetrating systems, exfiltrating and manipulating data, and taking services offline through denial-of-service attacks and delivery of ransomware payloads. Threat actors have relayed their command and control (C2) server communications—used to control systems infected with malware—through Tor, obscuring the identity (location and ownership) of those servers.

The use of Tor in this context allows threat actors to remain anonymous, making it difficult for network defenders and authorities to perform system recovery and respond to cyberattacks. Organizations that do not take steps to block or monitor Tor traffic are at heightened risk of being targeted and exploited by threat actors hiding their identity and intentions using Tor.

The risk of being the target of malicious activity routed through Tor is unique to each organization. An organization should determine its individual risk by assessing the likelihood that a threat actor will target its systems or data and the probability of the threat actor’s success given current mitigations and controls. This assessment should consider legitimate reasons that non-malicious users may prefer to, or need to, use Tor for accessing the network. Organizations should evaluate their mitigation decisions against threats to their organization from advanced persistent threats (APTs), moderately sophisticated attackers, and low-skilled individual hackers, all of whom have leveraged Tor to carry out reconnaissance and attacks in the past.

Technical Details

Tor obfuscates the source and destination of a web request. This allows users to conceal information about their activities on the web—such as their location and network usage—from the recipients of that traffic, as well as third parties who may conduct network surveillance or traffic analysis. Tor encrypts a user’s traffic and routes the traffic through at least three Tor nodes, or relays, so that the user’s starting IP address and request is masked from network and traffic observers during transit. Once the request reaches its intended destination, it exits Tor through a public Tor exit node. Anyone conducting monitoring or analysis will only see the traffic coming from the Tor exit node and will not be able to determine the original IP address of the request.

 

Figure 1: Malicious tactics and techniques aided by Tor, mapped to the MITRE ATT&CK framework

Malicious Tactics and Techniques Aided by Tor

Threat actors use Tor to create a layer of anonymity to conceal malicious activity at different stages of network compromise. Their tactics and techniques—illustrated in figure 1 above—include:

Pre-ATT&CK
  • Target Selection [TA0014]
  • Technical Information Gathering [TA0015]
    • Conduct Active Scanning [T1254]
    • Conduct Passive Scanning [T1253]
    • Determine domain and IP address space [T1250]
    • Identify security defensive capabilities [T1263]
  • Technical Weakness Identification [TA0018]
ATT&CK Key Indicators of Malicious Activity via Tor

While Tor obfuscates a user from being identified through standard security tools, network defenders can leverage various network, endpoint, and security appliance logs to detect the use of Tor, including potentially malicious activity involving Tor, through indicator- or behavior-based analysis.

Using an indicator-based approach, network defenders can leverage security information and event management (SIEM) tools and other log analysis platforms to flag suspicious activities involving the IP addresses of Tor exit nodes. The list of Tor exit node IP addresses is actively maintained by the Tor Project’s Exit List Service, which offers both real-time query and bulk download interfaces (see https://blog.torproject.org/changes-tor-exit-list-service). Organizations preferring bulk download may consider automated data ingest solutions, given the highly dynamic nature of the Tor exit list, which is updated hourly. Network defenders should closely inspect evidence of substantial transactions with Tor exit nodes—revealed in netflow, packet capture (PCAP), and web server logs—to infer the context of the activity and to discern any malicious behavior that could represent reconnaissance, exploitation, C2, or data exfiltration.

Using a behavior-based approach, network defenders can uncover suspicious Tor activity by searching for the operational patterns of Tor client software and protocols. Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) ports commonly affiliated with Tor include 9001, 9030, 9040, 9050, 9051, and 9150. Highly structured Domain Name Service (DNS) queries for domain names ending with the suffix torproject.org is another behavior exhibited by hosts running Tor software. In addition, DNS queries for domains ending in .onion is a behavior exhibited by misconfigured Tor clients, which may be attempting to beacon to malicious Tor hidden services.

Organizations should research and enable the pre-existing Tor detection and mitigation capabilities within their existing endpoint and network security solutions, as these often employ effective detection logic. Solutions such as web application firewalls, router firewalls, and host/network intrusion detection systems may already provide some level of Tor detection capability.

Mitigations

Organizations can implement mitigations of varying complexity and restrictiveness to reduce the risk posed by threat actors who use Tor to carry out malicious activities. However, mitigation actions can also impact the access of legitimate users who leverage Tor to protect their privacy when visiting an organization’s internet-facing assets. Organizations should evaluate their probable risk, available resources, and impact to legitimate, non-malicious, Tor users before applying mitigation actions. 

  • Most restrictive approach: Block all web traffic to and from public Tor entry and exit nodes. Organizations that wish to take a conservative or less resource-intensive approach to reduce the risk posed by threat actors’ use of Tor should implement tools that restrict all traffic—malicious and legitimate—to and from Tor entry and exit nodes. Of note, blocking known Tor nodes does not completely eliminate the threat of malicious actors using Tor for anonymity, as additional Tor network access points, or bridges, are not all listed publicly. See table 1 for the most restrictive mitigation practices.

Table 1: Most restrictive mitigation practices

Type Level of Effort Technical Implementation

Impact 

Baseline Activity Low/Medium

Require organization to maintain up-to-date lists of known Tor exit and entry node IP addresses.

Public lists are available on the internet, but frequency of updates and accuracy varies depending on the source. The Tor Project maintains an authoritative list

Up-to-date awareness of known Tor nodes to enable blocking External Policies Medium

Set external policies to block incoming traffic from known Tor exit nodes to prevent malicious reconnaissance and exploit attempts.

Network security tools (e.g., next-generation firewalls, proxies) may have configuration settings to apply these policies.

Block inbound network traffic, both malicious and legitimate, from reaching the organization’s domain from known Tor exit nodes Internal Policies Medium

Set internal policies to block outgoing traffic to Tor entry nodes to prevent data exfiltration and C2 traffic.

Network security tools (e.g., next-generation firewalls, proxies) may have configuration settings to apply these policies.

Block outbound network traffic, both malicious and legitimate, from leaving the organization’s domain into known Tor entry nodes

 

  • Less restrictive approach: Tailor monitoring, analysis, and blocking of web traffic to and from public Tor entry and exit nodes. There are instances in which legitimate users may leverage Tor for internet browsing and other non-malicious purposes. For example, deployed military or other overseas voters may use Tor as part of the voting process to escape monitoring by foreign governments. Such users may use Tor when visiting elections-related websites, to check voter registration status, or to mark and then cast absentee ballots via email or web portal. Similarly, some users may use Tor to avoid tracking by advertisers when browsing the internet. Organizations that do not wish to block legitimate traffic to/from Tor entry/exit nodes should consider adopting practices that allow for network monitoring and traffic analysis for traffic from those nodes, and then consider appropriate blocking. This approach can be resource intensive but will allow greater flexibility and adaptation of defensive.

Table 2: Less restrictive mitigation practices

Type Level of Effort Technical Implementation Impact Known Tor Nodes Low/Medium

Require the organization to maintain up-to-date lists of known Tor exit and entry node IP addresses.

The Tor Project maintains an authoritative list

Up-to-date awareness of known Tor nodes to enable baselining/allow blocking SIEM Correlation Low/Medium Integrate network security and SIEM tools that correlate logs. Enhanced understanding of legitimate/expected Tor use for inbound/outbound traffic Baseline Medium

Analyze traffic to determine normal patterns of behavior; legitimate vs. anomalous uses of Tor.

Baseline existing Tor traffic to/from known entry/exit nodes over a period of months.

Inspect traffic to understand legitimate traffic; level-set the organization’s risk tolerance for blocking or allowing Tor traffic to/from specific services.

Baseline understanding of legitimate vs. potentially anomalous Tor uses. Internal / External Policies Medium/High

Institute behavioral signatures/rules to block unexpected/potentially malicious activity and allow legitimate activity.

Examine activity between any ephemeral port and Tor IP—this could be malicious data exfiltration or C2 traffic (except where use of outbound Tor entry nodes is expected).

Monitor for use of TCP/UDP ports 9001, 9030, 9040, 9050, 9051, 9150, and TCP ports 443* and 8443.

Monitor and/or block inbound connections from Tor exit nodes to IP addresses and ports for which external connections are not expected (i.e., other than VPN gateways, mail ports, web ports).

Associated ports are applicable for client -> guard/relay traffic monitoring and analysis but not monitoring for exit node -> a network destination.

Monitor and examine any large dataflows between networks and Tor IP addresses, regardless of port, as this could be unauthorized data exfiltration.

*Since port 443 is the most common port for secure web traffic, generically monitoring 443 may produce a high volume of false positives; network traffic tools can be used to assist in this analysis.

Legitimate traffic via Tor entry/exit nodes is permitted and unexpected/potentially malicious activity via Tor entry/exit nodes is blocked

 

  • Blended approach: Block all Tor traffic to some resources, allow and monitor for others. Given the various licit and illicit uses of Tor, a blended approach may be an appropriate risk mitigation strategy for some organizations (i.e., intentionally allowing traffic to/from Tor only for specific websites and services where legitimate use may be expected and blocking all Tor traffic to/from non-excepted processes/services). This may require continuous re-evaluation as an entity considers its own risk tolerance associated with different applications. The level of effort to implement this approach is high.
Considerations for Blocking Use of Tor

Sophisticated threat actors may leverage additional anonymization technologies—such as virtual private networks (VPNs)—and configurable features within Tor—such as Tor bridges and pluggable transports—to circumvent detection and blocking. Blocking the use of known Tor nodes may not effectively mitigate all hazards but may protect against less sophisticated actors. For example, blocking outbound traffic to known Tor entry nodes could have an appreciable impact in blocking less sophisticated malware from successfully beaconing out to hidden C2 machines obfuscated by Tor. Ultimately, each entity must consider its own internal thresholds and risk tolerance when determining a risk mitigation approach associated with Tor.

Contact Information

To report suspicious or criminal activity related to information found in this Joint Cybersecurity Advisory, contact your local FBI field office at www.fbi.gov/contact-us/field, or the FBI’s 24/7 Cyber Watch (CyWatch) at (855) 292-3937 or by e-mail at CyWatch@fbi.gov. When available, please include the following information regarding the incident: date, time, and location of the incident; type of activity; number of people affected; type of equipment used for the activity; the name of the submitting company or organization; and a designated point of contact. To request incident response resources or technical assistance related to these threats, contact CISA at CISAServiceDesk@cisa.dhs.gov.

Disclaimer

This document is marked TLP:WHITE. Disclosure is not limited. Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction. For more information on the Traffic Light Protocol, see http://www.us-cert.gov/tlp/.

References Revisions
  • July 1, 2020: Initial Version

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

Categories: Security Alerts

Cisco AnyConnect Secure Mobility Client for Mac OS File Corruption Vulnerability

Cisco Security Advisories - Wed, 2020-07-01 16:00

A vulnerability in the uninstaller component of Cisco AnyConnect Secure Mobility Client for Mac OS could allow an authenticated, local attacker to corrupt the content of any file in the filesystem.

The vulnerability is due to the incorrect handling of directory paths. An attacker could exploit this vulnerability by creating a symbolic link (symlink) to a target file on a specific path. A successful exploit could allow the attacker to corrupt the contents of the file. If the file is a critical systems file, the exploit could lead to a denial of service condition. To exploit this vulnerability, the attacker would need to have valid credentials on the 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-anyconnect-mac-dos-36s2y3Lv


Security Impact Rating: Medium
CVE: CVE-2020-3432
Categories: Security Alerts

Cisco Small Business Smart and Managed Switches Session Management Vulnerability

Cisco Security Advisories - Wed, 2020-07-01 16:00

A vulnerability in session management for the web-based interface of Cisco Small Business Smart and Managed Switches could allow an unauthenticated, remote attacker to defeat authentication protections and gain unauthorized access to the management interface. The attacker could obtain the privileges of the highjacked session account, which could include administrator privileges on the device.

The vulnerability is due to the use of weak entropy generation for session identifier values. An attacker could exploit this vulnerability to determine a current session identifier through brute force and reuse that session identifier to take over an ongoing session. In this way, an attacker could take actions within the management interface with privileges up to the level of the administrative user.

Cisco has released software updates that address this vulnerability for devices that have not reached the end of software maintenance. 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-sbswitch-session-JZAS5jnY


Security Impact Rating: High
CVE: CVE-2020-3297
Categories: Security Alerts

Cisco Small Business RV042 and RV042G Routers Cross-Site Scripting Vulnerability

Cisco Security Advisories - Wed, 2020-07-01 16:00

A vulnerability in the web-based management interface of Cisco Small Business RV042 Dual WAN VPN Routers and Cisco Small Business RV042G Dual Gigabit WAN VPN Routers could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the web-based management interface of an affected device.

The vulnerability is due to insufficient validation of user-supplied input by the web-based management interface of the affected software. An attacker could exploit this vulnerability by persuading a user of the interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive browser-based information.

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-sa-rv-routers-xss-K7Z5U6q3


Security Impact Rating: Medium
CVE: CVE-2020-3431
Categories: Security Alerts

Cisco Identity Services Engine Stored Cross-Site Scripting Vulnerabilities

Cisco Security Advisories - Wed, 2020-07-01 16:00

Multiple vulnerabilities in the web-based management interface of Cisco Identity Services Engine (ISE) could allow an authenticated, remote attacker with administrative credentials to conduct a cross-site scripting (XSS) attack against a user of the interface.

These vulnerabilities are due to insufficient validation of user-supplied input that is processed by the web-based management interface. An attacker could exploit these vulnerabilities by injecting malicious code into specific pages of the interface. A successful exploit could allow the attacker to execute arbitrary script code in the context of the interface or access sensitive, browser-based information. To exploit these vulnerabilities, an attacker would need valid administrative credentials.

Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-mlt-ise-strd-xss-nqFhTtx7


Security Impact Rating: Medium
CVE: CVE-2020-3340
Categories: Security Alerts

Cisco Digital Network Architecture Center Information Disclosure Vulnerability

Cisco Security Advisories - Wed, 2020-07-01 16:00

A vulnerability in Cisco Digital Network Architecture (DNA) Center could allow an authenticated, remote attacker to view sensitive information in clear text.

The vulnerability is due to insecure storage of certain unencrypted credentials on an affected device. An attacker could exploit this vulnerability by viewing the network device configuration and obtaining credentials that they may not normally have access to. A successful exploit could allow the attacker to use those credentials to discover and manage network devices.

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-dnac-info-disc-6xsCyDYy


Security Impact Rating: Medium
CVE: CVE-2020-3391
Categories: Security Alerts

Cisco Unified Customer Voice Portal Information Disclosure Vulnerability

Cisco Security Advisories - Wed, 2020-07-01 16:00

A vulnerability in the Java Remote Method Invocation (RMI) interface of Cisco Unified Customer Voice Portal (CVP) could allow an unauthenticated, remote attacker to access sensitive information on an affected device.

The vulnerability exists because certain RMI listeners are not properly authenticated. An attacker could exploit this vulnerability by sending a crafted request to the affected listener. A successful exploit could allow the attacker to access sensitive information on an 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-cvp-info-dislosure-NZBEwj9V


Security Impact Rating: Medium
CVE: CVE-2020-3402
Categories: Security Alerts

Cisco Unified Communications Manager Stored Cross-Site Scripting Vulnerability

Cisco Security Advisories - Wed, 2020-07-01 16:00

A vulnerability in the web-based management interface of Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) could allow an authenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the interface.

The vulnerability is due to insufficient validation of user-supplied input by the web-based management interface of the affected software. An attacker could exploit this vulnerability by inserting malicious data into a specific data field in the interface. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive browser-based information.

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-cucm-xss-bLZw4Ctq


Security Impact Rating: Medium
CVE: CVE-2020-3420
Categories: Security Alerts

Cisco Unified Communications Products Cross-Site Scripting Vulnerability

Cisco Security Advisories - Wed, 2020-07-01 16:00

A vulnerability in the web-based management interface of Cisco Unified Communications Manager, Cisco Unified Communications Manager Session Management Edition, Cisco Unified Communications Manager IM & Presence Service, and Cisco Unity Connection could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the interface.

The vulnerability is due to insufficient validation of user-supplied input by the web-based management interface of the affected software. An attacker could exploit this vulnerability by persuading a user of the interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive browser-based information.

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-cucm-cuc-imp-xss-OWuSYAp


Security Impact Rating: Medium
CVE: CVE-2020-3282
Categories: Security Alerts

AA20-182A: EINSTEIN Data Trends – 30-day Lookback

US-CERT - Tue, 2020-06-30 07:34
Original release date: June 30, 2020
Summary

Cybersecurity and Infrastructure Security Agency (CISA) analysts have compiled the top detection signatures that have been the most active over the month of May in our national Intrusion Detection System (IDS), known as EINSTEIN. This information is meant to give the reader a closer look into what analysts are seeing at the national level and provide technical details on some of the most active threats.

IDS is a network tool that uses sensors to monitor inbound and outbound traffic to search for any type of suspicious activity or known threats, alerting analysts when a specific traffic pattern matches with an associated threat. IDS allows users to deploy signatures on these boundary sensors to look for the specific pattern, or network indicator, associated with a known threat.

The EINSTEIN Program is an automated process for collecting, correlating, analyzing, and sharing computer security information across the federal civilian government. By collecting information from participating federal government agencies, CISA builds and enhances our Nation’s cyber-related situational awareness.

The signatures CISA created have been included below for analysts across various organizations to use in enhancing their own network defenses. Note: CISA has created and tested these signatures in an environment that might not be the same for all organizations, so administrators may need to make changes or updates before using in the following signatures in their local environments.

Technical Details

Note: the below Snort signatures accounted for over 90 percent of what CISA analysts identified as potential threats using the IDS system for detection.

1. NetSupport Manager RAT Description

The NetSupport Manager Remote Access Tool (RAT) is a legitimate program that, once installed on a victim’s machine, allows remote administrative control. In a malicious context, it can—among many other functions—be used to steal information. Malicious RATs can be difficult to detect because they do not normally appear in lists of running programs, and they can mimic the behavior of legitimate applications.

Examples

In January 2020, Palo Alto researchers observed the abuse of NetSupport in targeted phishing email campaigns.[1] In November 2019, Zscaler researchers observed “software update-themed” campaigns tricking users into installing a malicious NetSupport Manager RAT.[2] The earliest malicious use of NetSupport was seen in a phishing email campaign—reported by FireEye researchers in April 2018.[3]

Snort Signature alert tcp any any -> any $HTTP_PORTS (msg:"NetSupportManager:HTTP Client Header contains 'User-Agent|3a 20|NetSupport Manager/'"; flow:established,to_server; flowbits:isnotset,.tagged; content:"User-Agent|3a 20|NetSupport Manager/"; http_header; fast_pattern:only; content:"CMD="; nocase; http_client_body; depth:4; content:"POST"; nocase; http_method; flowbits:set,.; classtype:http-header; reference:url,unit42.paloaltonetworks.com/cortex-xdr-detects-netsupport-manager-rat-campaign/; reference:url,www.pentestpartners.com/security-blog/how-to-reverse-engineer-a-protocol/; reference:url,github.com/silence-is-best/c2db; 2. Kovter Description

Kovter is a fileless Trojan with several variants. This malware started as ransomware that malicious actors used to trick victims into thinking that they need to pay their local police a fine. Cyber actors have also used Kovter to perform click-fraud operations to infect targets and send stolen information from the target machines to command and control servers. Kovter’s evolving features have allowed this malware to rank among the Center for Internet Security’s most prolific malware year after year.[4] See CISA’s Webinar on Combatting Ransomware for additional information on Kovter.

Snort Signature alert tcp any any -> any $HTTP_PORTS (msg:"Kovter:HTTP URI POST to CnC Server";; flow:established,to_server; flowbits:isnotset,.tagged; content:"POST / HTTP/1.1"; depth:15; content:"Content-Type|3a 20|application/x-www-form-urlencoded"; http_header; depth:47; fast_pattern; content:"User-Agent|3a 20|Mozilla/"; http_header; content:!"LOADCURRENCY"; nocase; content:!"Accept"; http_header; content:!"Referer|3a|"; http_header; content:!"Cookie|3a|"; nocase; http_header; pcre:"/^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=|[A-Za-z0-9+\/]{4})$/P"; pcre:"/User-Agent\x3a[^\r\n]+\r\nHost\x3a\x20(?:\d{1,3}\.){3}\d{1,3}\r\nContent-Length\x3a\x20[1-5][0-9]{2,3}\r\n(?:Cache-Control|Pragma)\x3a[^\r\n]+\r\n(?:\r\n)?$/H";; classtype:nonstd-tcp;; reference:url,www.malware-traffic-analysis.net/2017/06/29/index2.html; 3. XMRig Description

XMRig is a type of cryptocurrency miner that uses the resources of an unsuspecting infected machine to mine Monero—a type of cryptocurrency. XMRig can cause a victim computer to overheat and perform poorly by using additional system resources that would otherwise not be active.

Snort Signature alert tcp any any -> any !25 (msg:"XMRIG:Non-Std TCP Client Traffic contains JSONRPC 2.0 Config Data";; flow:established,to_server; flowbits:isnotset; content:"|22|jsonrpc|22 3a 22|2.0|22|"; distance:0; content:"|22|method|22 3a 22|login|22|"; distance:0; content:"|22|agent|22 3a 22|XMRig"; nocase; distance:0; fast_pattern; content:"libuv/"; nocase; distance:0; content:!"|22|login|22 3a 22|x|22|"; flowbits:set,; classtype:nonstd-tcp;; reference:url,malware-traffic-analysis.net/2017/11/12/index.html; reference:url,www.mysonicwall.com/sonicalert/searchresults.aspx?ev=article&id=1101; Mitigations

CISA recommends using the following best practices to strengthen the security posture of an organization's systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.

  • Maintain up-to-date antivirus signatures and engines. See Protecting Against Malicious Code.
  • Ensure systems have the latest security updates. See Understanding Patches and Software Updates.
  • Disable file and printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
  • Restrict users' permissions to install and run unwanted software applications. Do not add users to the local administrators’ group unless required.
  • Enforce a strong password policy. See Choosing and Protecting Passwords.
  • Exercise caution when opening email attachments, even if the attachment is expected and the sender appears to be known. See Using Caution with Email Attachments.
  • Enable a personal firewall on agency workstations that is configured 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 prior to executing.
  • Maintain situational awareness of the latest threats and implement appropriate Access Control Lists (ACLs). Sign up to receive CISA’s alerts on security topics and threats.
  • Sign up for CISA’s free vulnerability scanning and testing services to help organizations secure internet-facing systems from weak configuration and known vulnerabilities. Email vulnerability_info@cisa.dhs.gov to sign up. See https://www.cisa.gov/cyber-resource-hub for more information about vulnerability scanning and other CISA cybersecurity assessment services.
Resources

https://unit42.paloaltonetworks.com/cortex-xdr-detects-netsupport-manager-rat-campaign/
https://threatpost.com/netsupport-manager-rat-nortonlifelock-docs/153387/
https://www.zdnet.com/article/new-lokibot-trojan-malware-campaign-comes-disguised-as-a-popular-game-launcher/
https://www.trendmicro.com/vinfo/us/security/news/cybercrime-and-digital-threats/kovter-an-evolving-malware-gone-fileless
https://www.varonis.com/blog/what-is-mimikatz/

References Revisions
  • June 30, 2020: Initial Version

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

Categories: Security Alerts

Telnet Vulnerability Affecting Cisco Products: June 2020

Cisco Security Advisories - Wed, 2020-06-24 16:00

On February 28, 2020, APPGATE published a blog post regarding CVE-ID CVE-2020-10188, which is a vulnerability in Telnet servers (telnetd).

For more information about this vulnerability, see the Details section.

Cisco will release 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-telnetd-EFJrEzPx


Security Impact Rating: High
CVE: CVE-2020-10188
Categories: Security Alerts

Multiple Vulnerabilities in Treck IP Stack Affecting Cisco Products: June 2020

Cisco Security Advisories - Wed, 2020-06-17 20:00

A set of previously unknown vulnerabilities on the Treck IP stack implementation were disclosed on June 16, 2020. The vulnerabilities are collectively known as Ripple20. Exploitation of these vulnerabilities could result in remote code execution, denial of service (DoS), or information disclosure, depending on the specific vulnerability.

This advisory will be updated as additional information becomes available.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-treck-ip-stack-JyBQ5GyC


Security Impact Rating: Critical
CVE: CVE-2020-11896,CVE-2020-11897,CVE-2020-11898,CVE-2020-11899,CVE-2020-11900,CVE-2020-11901,CVE-2020-11902,CVE-2020-11903,CVE-2020-11904,CVE-2020-11905,CVE-2020-11906,CVE-2020-11907,CVE-2020-11908,CVE-2020-11909,CVE-2020-11910,CVE-2020-11911,CVE-2020-11912,CVE-2020-11913,CVE-2020-11914
Categories: Security Alerts

Cisco Webex Meetings Desktop App for Windows Shared Memory Information Disclosure Vulnerability

Cisco Security Advisories - Wed, 2020-06-17 16:27

A vulnerability in Cisco Webex Meetings Desktop App for Windows could allow an authenticated, local attacker to gain access to sensitive information on an affected system.

The vulnerability is due to unsafe usage of shared memory that is used by the affected software. An attacker with permissions to view system memory could exploit this vulnerability by running an application on the local system that is designed to read shared memory. A successful exploit could allow the attacker to retrieve sensitive information from the shared memory, including usernames, meeting information, or authentication tokens that could aid the attacker in future attacks.

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-client-NBmqM9vt


Security Impact Rating: Medium
CVE: CVE-2020-3347
Categories: Security Alerts

Cisco ASR 5000 Series Aggregation Services Routers Enhanced Charging Service Rule Bypass Vulnerability

Cisco Security Advisories - Wed, 2020-06-17 16:00

A vulnerability in the Enhanced Charging Service (ECS) functionality of Cisco ASR 5000 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to bypass the traffic classification rules on an affected device.

The vulnerability is due to insufficient input validation of user traffic going through an affected device. An attacker could exploit this vulnerability by sending a malformed HTTP request to an affected device. A successful exploit could allow the attacker to bypass the traffic classification rules and potentially avoid being charged for traffic consumption.

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-asr5k-ecs-bypass-2LqfPCL


Security Impact Rating: Medium
CVE: CVE-2020-3244
Categories: Security Alerts

Cisco IOS XR Software Standby Route Processor Gigabit Ethernet Management Interface Access Control List Bypass Vulnerability

Cisco Security Advisories - Wed, 2020-06-17 16:00

A vulnerability in the access control list (ACL) functionality of the standby route processor management interface of Cisco IOS XR Software could allow an unauthenticated, remote attacker to reach the configured IP addresses on the standby route processor management Gigabit Ethernet Management interface.

The vulnerability is due to a logic error that was introduced in the Cisco IOS XR Software, which prevents the ACL from working when applied against the standby route processor management interface. An attacker could exploit this vulnerability by attempting to access the device through the standby route processor management interface.

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-xracl-zbWSWREt


Security Impact Rating: Medium
CVE: CVE-2020-3364
Categories: Security Alerts

Cisco Webex Meetings and Cisco Webex Meetings Server Token Handling Unauthorized Access Vulnerability

Cisco Security Advisories - Wed, 2020-06-17 16:00

A vulnerability in Cisco Webex Meetings and Cisco Webex Meetings Server could allow an unauthenticated, remote attacker to gain unauthorized access to a vulnerable Webex site.

The vulnerability is due to improper handling of authentication tokens by a vulnerable Webex site. An attacker could exploit this vulnerability by sending crafted requests to a vulnerable Cisco Webex Meetings or Cisco Webex Meetings Server site. If successful, the attacker could gain the privileges of another user within the affected Webex site.

Cisco has released software updates that address this vulnerability. Customers on Cisco hosted Webex Meetings sites do not need to take any actions to receive this update. 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-token-zPvEjKN


Security Impact Rating: High
CVE: CVE-2020-3361
Categories: Security Alerts

Cisco Webex Meetings Desktop App URL Filtering Arbitrary Program Execution Vulnerability

Cisco Security Advisories - Wed, 2020-06-17 16:00

A vulnerability in Cisco Webex Meetings Desktop App could allow an unauthenticated, remote attacker to execute programs on an affected end-user system.

The vulnerability is due to improper validation of input that is supplied to application URLs. The attacker could exploit this vulnerability by persuading a user to follow a malicious URL. A successful exploit could allow the attacker to cause the application to execute other programs that are already present on the end-user system. If malicious files are planted on the system or on an accessible network file path, the attacker could execute arbitrary code on 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-webex-client-url-fcmpdfVY


Security Impact Rating: High
CVE: CVE-2020-3263
Categories: Security Alerts

Cisco Webex Meetings Desktop App for Mac Update Feature Code Execution Vulnerability

Cisco Security Advisories - Wed, 2020-06-17 16:00

A vulnerability in the software update feature of Cisco Webex Meetings Desktop App for Mac could allow an unauthenticated, remote attacker to execute arbitrary code on an affected system.

The vulnerability is due to improper validation of cryptographic protections on files that are downloaded by the application as part of a software update. An attacker could exploit this vulnerability by persuading a user to go to a website that returns files to the client that are similar to files that are returned from a valid Webex website. The client may fail to properly validate the cryptographic protections of the provided files before executing them as part of an update. A successful exploit could allow the attacker to execute arbitrary code on the affected system with the privileges of the user.

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-client-mac-X7vp65BL


Security Impact Rating: High
CVE: CVE-2020-3342
Categories: Security Alerts

Cisco Umbrella Open Redirect Vulnerability

Cisco Security Advisories - Wed, 2020-06-17 16:00

A vulnerability in the web server of Cisco Umbrella could allow an unauthenticated, remote attacker to redirect a user to an undesired web page.

The vulnerability is due to improper input validation of the URL parameters in an HTTP request that is sent to an affected device. An attacker could exploit this vulnerability by sending a crafted HTTP request that could cause the web application to redirect the request to a specified malicious URL. A successful exploit could allow the attacker to redirect a user to a malicious website.

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-umbrella-open-redire-UgK9dWK4


Security Impact Rating: Medium
CVE: CVE-2020-3337
Categories: Security Alerts

Cisco UCS Director Path Traversal Vulnerability

Cisco Security Advisories - Wed, 2020-06-17 16:00

A vulnerability in the orchestration tasks of Cisco UCS Director could allow an authenticated, remote attacker to perform a path traversal attack on an affected device.

The vulnerability is due to insufficient validation of user-supplied input on the web-based management interface. An attacker could exploit this vulnerability by creating a task with specific configuration parameters. A successful exploit could allow the attacker to overwrite arbitrary files in the file system of an 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-ucsd-task-path-trav-d67ZuAk7


Security Impact Rating: Medium
CVE: CVE-2020-3241
Categories: Security Alerts

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