Brave Browser — CraftedSignal Threat Feedhttps://feed.craftedsignal.io/products/brave-browser/Trending threats, MITRE ATT&CK coverage, and detection metadata — refreshed continuously.Hugoenhello@craftedsignal.iohello@craftedsignal.ioWed, 31 Jan 2024 12:00:00 +0000Suspicious Child Processes from Communication Applicationshttps://feed.craftedsignal.io/briefs/2024-01-suspicious-comm-app-child-process/Wed, 31 Jan 2024 12:00:00 +0000hello@craftedsignal.iohttps://feed.craftedsignal.io/briefs/2024-01-suspicious-comm-app-child-process/The detection rule identifies suspicious child processes spawned from communication applications on Windows systems, potentially indicating masquerading or exploitation of vulnerabilities within these applications.This detection rule focuses on identifying suspicious child processes of communication applications such as Slack, Cisco Webex, Microsoft Teams, Discord, WhatsApp, Zoom, and Thunderbird on Windows operating systems. Attackers may attempt to masquerade as legitimate processes or exploit vulnerabilities in these applications to execute malicious code. The rule monitors for the creation of child processes by these communication apps and checks if those child processes are unexpected, untrusted, or lack a valid code signature. This detection is crucial because successful exploitation can lead to unauthorized access, data exfiltration, or further compromise of the system. The rule has been actively maintained since August 2023, with updates as recent as May 2026, indicating its relevance and ongoing refinement to address emerging threats.

Attack Chain

  1. User launches a communication application (e.g., Slack, Teams, Webex).
  2. The communication application executes a vulnerable or compromised component.
  3. The compromised component spawns a child process (e.g., powershell.exe, cmd.exe).
  4. The child process executes a malicious command or script.
  5. The script attempts to download additional payloads from an external source.
  6. The payload executes, establishing persistence through registry modification or scheduled tasks.
  7. The attacker gains remote access to the system.
  8. Data exfiltration or lateral movement within the network occurs.

Impact

A successful attack can lead to the compromise of sensitive data, installation of malware, and potential lateral movement within the organization’s network. By exploiting communication applications, attackers can gain access to internal communications, confidential documents, and user credentials. The number of affected users and the extent of the damage depend on the compromised application and the attacker’s objectives. If successful, this attack may lead to significant financial loss, reputational damage, and disruption of business operations.

Recommendation

  • Deploy the Sigma rule Suspicious Communication App Child Process to your SIEM to detect anomalous child processes spawned by communication applications and tune for your environment.
  • Enable process creation logging with command line arguments in Windows to ensure that the Sigma rule has the necessary data to function correctly (logsource: process_creation, product: windows).
  • Investigate any alerts generated by the rule and review the command line arguments of the spawned processes to identify potential malicious activity.
  • Implement application whitelisting to restrict the execution of unauthorized applications and reduce the attack surface.
  • Ensure that all communication applications are updated to the latest versions to patch known vulnerabilities and reduce the risk of exploitation.
  • Examine the network activity of the affected system to identify any suspicious outbound connections that may indicate data exfiltration or communication with a command and control server, referencing the setup guide.
]]>mediumadvisorydefense-evasionpersistencewindowsRMM Domain DNS Queries from Non-Browser Processeshttps://feed.craftedsignal.io/briefs/2024-01-rmm-domain-dns/Wed, 03 Jan 2024 12:00:00 +0000hello@craftedsignal.iohttps://feed.craftedsignal.io/briefs/2024-01-rmm-domain-dns/Detects DNS queries to commonly abused remote monitoring and management (RMM) or remote access software domains from non-browser processes, potentially indicating unauthorized remote access or command and control activity.This detection identifies potentially malicious use of Remote Monitoring and Management (RMM) tools by detecting DNS queries to known RMM domains originating from processes that are not web browsers. Attackers frequently abuse legitimate RMM software for command and control, persistence, and lateral movement within compromised networks. This rule focuses on surfacing RMM clients, scripts, or other non-browser activity contacting these services, thereby increasing the likelihood of detecting unauthorized remote access or malicious activity. The rule aims to reduce false positives by excluding common browser processes and focusing on unusual network activity. The identified domains are associated with various RMM tools like TeamViewer, AnyDesk, and ScreenConnect. This detection is relevant for organizations concerned about insider threats, supply chain attacks, or general compromise leading to unauthorized remote access.

Attack Chain

  1. An attacker gains initial access to a system, possibly through phishing or exploiting a vulnerability.
  2. The attacker installs an unauthorized RMM tool (e.g., using a script or installer).
  3. The RMM tool initiates a DNS query to resolve its command and control domain (e.g., teamviewer.com).
  4. The system, now running the RMM agent, establishes a connection to the attacker-controlled RMM server.
  5. The attacker uses the RMM tool to execute commands on the compromised system.
  6. The attacker uses the RMM tool for lateral movement within the network.
  7. The attacker uses the RMM tool to maintain persistence on the compromised system.

Impact

Compromise via unauthorized RMM tools can provide attackers with persistent remote access, enabling them to perform a range of malicious activities, including data theft, ransomware deployment, and further lateral movement within the network. Successful exploitation can lead to significant financial loss, reputational damage, and disruption of business operations. The number of affected systems can vary depending on the scope of the initial compromise and the attacker’s ability to move laterally.

Recommendation

  • Deploy the Sigma rule RMM Domain DNS Queries from Non-Browser Processes to your SIEM and tune it to your environment, excluding legitimate non-browser processes that use RMM tools.
  • Investigate any alerts generated by the rule, focusing on identifying the process making the DNS query and its parent process, as outlined in the rule’s description.
  • Monitor DNS query logs for queries to the RMM domains listed in the IOC table, and block them at the DNS resolver if unauthorized RMM use is confirmed.
  • Enable Sysmon Event ID 22 (DNS Query) logging to provide the necessary data for this detection, as recommended in the “Setup” section of the content.
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