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Potential RemoteMonologue Attack

Identifies attempt to perform session hijack via COM object registry modification by setting the RunAs value to Interactive User.

Rule type: eql
Rule indices:

  • logs-endpoint.events.registry-*
  • endgame-*
  • logs-m365_defender.event-*
  • logs-sentinel_one_cloud_funnel.*
  • logs-windows.sysmon_operational-*

Rule Severity: medium
Risk Score: 47
Runs every:
Searches indices from: now-9m
Maximum alerts per execution: 100
References:

Tags:

  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Defense Evasion
  • Data Source: Elastic Defend
  • Data Source: Elastic Endgame
  • Data Source: Microsoft Defender XDR
  • Data Source: SentinelOne
  • Data Source: Sysmon
  • Resources: Investigation Guide

Version: 7
Rule authors:

  • Elastic

Rule license: Elastic License v2

This rule is designed for data generated by Elastic Defend, which provides native endpoint detection and response, along with event enrichments designed to work with our detection rules.

Setup instructions: https://ela.st/install-elastic-defend

This rule also supports the following third-party data sources. For setup instructions, refer to the links below:

  • Review the registry event logs to confirm the modification of the RunAs value in the specified registry paths, ensuring the change was not part of a legitimate administrative action.
  • Identify the user account and process responsible for the registry modification by examining the event logs for associated user and process information.
  • Check for any recent remote authentication attempts or sessions on the affected host to determine if this activity is associated with lateral movement or not.
  • Investigate the timeline of the registry change to correlate with any other suspicious activities or alerts on the host, such as the execution of unusual processes or network connections.
  • Software updates or installations that modify COM settings.
  • Automated scripts or management tools that adjust COM configurations.
  • Immediately isolate the affected system from the network to prevent further unauthorized access or lateral movement by the adversary.
  • Modify the registry value back to its secure state, ensuring that "RunAs" value is not set to "Interactive User".
  • Conduct a thorough review of recent user activity and system logs to identify any unauthorized access or changes made during the period NLA was disabled.
  • Reset passwords for all accounts that have accessed the affected system to mitigate potential credential compromise.
  • Escalate the incident to the security operations center (SOC) or incident response team for further investigation and to determine if additional systems are affected.
  • Implement enhanced monitoring on the affected system and similar endpoints to detect any further attempts to disable NLA or other suspicious activities.
registry where host.os.type == "windows" and event.action != "deletion" and
  registry.value == "RunAs" and registry.data.strings : "Interactive User" and

  not
  (
    (
      process.executable : (
        "C:\\ProgramData\\Microsoft\\Windows Defender\\Platform\\4.*\\MsMpEng.exe",
        "C:\\Program Files\\Windows Defender\\MsMpEng.exe"
      ) and
      registry.path : "*\\SOFTWARE\\Classes\\AppID\\{1111A26D-EF95-4A45-9F55-21E52ADF9887}\\RunAs"
    ) or
    (
      process.executable : (
        "C:\\Program Files\\TeamViewer\\TeamViewer.exe",
        "C:\\Program Files (x86)\\TeamViewer\\TeamViewer.exe"
      ) and
      registry.path : "*\\SOFTWARE\\Classes\\AppID\\{850A928D-5456-4865-BBE5-42635F1EBCA1}\\RunAs"
    ) or
    (
      process.executable : "C:\\Windows\\System32\\svchost.exe" and
      registry.path : "*\\S-1-*Classes\\AppID\\{D3E34B21-9D75-101A-8C3D-00AA001A1652}\\RunAs"
    ) or
    (
      process.executable : "C:\\Windows\\System32\\SecurityHealthService.exe" and
      registry.path : (
        "*\\SOFTWARE\\Classes\\AppID\\{1D278EEF-5C38-4F2A-8C7D-D5C13B662567}\\RunAs",
        "*\\SOFTWARE\\Classes\\AppID\\{7E55A26D-EF95-4A45-9F55-21E52ADF9878}\\RunAs"
      )
    ) or
    (
      process.executable : "C:\\Windows\\System32\\SecurityHealthService.exe" and
      registry.path : (
        "*\\SOFTWARE\\Classes\\AppID\\{1D278EEF-5C38-4F2A-8C7D-D5C13B662567}\\RunAs",
        "*\\SOFTWARE\\Classes\\AppID\\{7E55A26D-EF95-4A45-9F55-21E52ADF9878}\\RunAs"
      )
    ) or
    registry.path : (
      "HKLM\\SOFTWARE\\Microsoft\\Office\\ClickToRun\\VREGISTRY_*",
      "\\REGISTRY\\MACHINE\\SOFTWARE\\Microsoft\\Office\\ClickToRun\\VREGISTRY_*"
    ) or
    (process.executable : "C:\\windows\\System32\\msiexec.exe" and ?user.id : "S-1-5-18")
  )

Framework: MITRE ATT&CK

Framework: MITRE ATT&CK