Potential RemoteMonologue Attack

  1[metadata]
  2creation_date = "2025/04/14"
  3integration = ["endpoint", "m365_defender", "sentinel_one_cloud_funnel", "windows"]
  4maturity = "production"
  5updated_date = "2025/08/08"
  6
  7[rule]
  8author = ["Elastic"]
  9description = """
 10Identifies attempt to perform session hijack via COM object registry modification by setting the RunAs value to
 11Interactive User.
 12"""
 13from = "now-9m"
 14index = [
 15    "logs-endpoint.events.registry-*",
 16    "endgame-*",
 17    "logs-m365_defender.event-*",
 18    "logs-sentinel_one_cloud_funnel.*",
 19    "logs-windows.sysmon_operational-*",
 20]
 21language = "eql"
 22license = "Elastic License v2"
 23name = "Potential RemoteMonologue Attack"
 24note = """## Triage and analysis
 25
 26### Investigating Potential RemoteMonologue Attack
 27
 28
 29### Possible investigation steps
 30
 31- 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.
 32- Identify the user account and process responsible for the registry modification by examining the event logs for associated user and process information.
 33- 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.
 34- 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.
 35
 36### False positive analysis
 37
 38- Software updates or installations that modify COM settings.
 39- Automated scripts or management tools that adjust COM configurations.
 40
 41### Response and remediation
 42
 43- Immediately isolate the affected system from the network to prevent further unauthorized access or lateral movement by the adversary.
 44- Modify the registry value back to its secure state, ensuring that "RunAs" value is not set to "Interactive User".
 45- 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.
 46- Reset passwords for all accounts that have accessed the affected system to mitigate potential credential compromise.
 47- Escalate the incident to the security operations center (SOC) or incident response team for further investigation and to determine if additional systems are affected.
 48- Implement enhanced monitoring on the affected system and similar endpoints to detect any further attempts to disable NLA or other suspicious activities.
 49"""
 50references = [
 51    "https://www.ibm.com/think/x-force/remotemonologue-weaponizing-dcom-ntlm-authentication-coercions#1",
 52    "https://github.com/xforcered/RemoteMonologue",
 53]
 54risk_score = 47
 55rule_id = "c18975f5-676c-4091-b626-81e8938aa2ee"
 56severity = "medium"
 57tags = [
 58    "Domain: Endpoint",
 59    "OS: Windows",
 60    "Use Case: Threat Detection",
 61    "Tactic: Defense Evasion",
 62    "Data Source: Elastic Defend",
 63    "Data Source: Elastic Endgame",
 64    "Data Source: Microsoft Defender for Endpoint",
 65    "Data Source: SentinelOne",
 66    "Data Source: Sysmon",
 67    "Resources: Investigation Guide",
 68]
 69timestamp_override = "event.ingested"
 70type = "eql"
 71
 72query = '''
 73registry where host.os.type == "windows" and event.action != "deletion" and
 74  registry.value == "RunAs" and registry.data.strings : "Interactive User" and
 75
 76  not 
 77  (
 78    (
 79      process.executable : (
 80        "C:\\ProgramData\\Microsoft\\Windows Defender\\Platform\\4.*\\MsMpEng.exe",
 81        "C:\\Program Files\\Windows Defender\\MsMpEng.exe"
 82      ) and
 83      registry.path : "*\\SOFTWARE\\Classes\\AppID\\{1111A26D-EF95-4A45-9F55-21E52ADF9887}\\RunAs"
 84    ) or
 85    (
 86      process.executable : (
 87        "C:\\Program Files\\TeamViewer\\TeamViewer.exe",
 88        "C:\\Program Files (x86)\\TeamViewer\\TeamViewer.exe"
 89      ) and
 90      registry.path : "*\\SOFTWARE\\Classes\\AppID\\{850A928D-5456-4865-BBE5-42635F1EBCA1}\\RunAs"
 91    ) or
 92    (
 93      process.executable : "C:\\Windows\\System32\\svchost.exe" and
 94      registry.path : "*\\S-1-*Classes\\AppID\\{D3E34B21-9D75-101A-8C3D-00AA001A1652}\\RunAs"
 95    ) or
 96    (
 97      process.executable : "C:\\Windows\\System32\\SecurityHealthService.exe" and
 98      registry.path : (
 99        "*\\SOFTWARE\\Classes\\AppID\\{1D278EEF-5C38-4F2A-8C7D-D5C13B662567}\\RunAs",
100        "*\\SOFTWARE\\Classes\\AppID\\{7E55A26D-EF95-4A45-9F55-21E52ADF9878}\\RunAs"
101      )
102    ) or
103    (
104      process.executable : "C:\\Windows\\System32\\SecurityHealthService.exe" and
105      registry.path : (
106        "*\\SOFTWARE\\Classes\\AppID\\{1D278EEF-5C38-4F2A-8C7D-D5C13B662567}\\RunAs",
107        "*\\SOFTWARE\\Classes\\AppID\\{7E55A26D-EF95-4A45-9F55-21E52ADF9878}\\RunAs"
108      )
109    ) or
110    registry.path : (
111      "HKLM\\SOFTWARE\\Microsoft\\Office\\ClickToRun\\VREGISTRY_*",
112      "\\REGISTRY\\MACHINE\\SOFTWARE\\Microsoft\\Office\\ClickToRun\\VREGISTRY_*"
113    ) or
114    (process.executable : "C:\\windows\\System32\\msiexec.exe" and user.id : "S-1-5-18")
115  )
116'''
117
118
119[[rule.threat]]
120framework = "MITRE ATT&CK"
121[[rule.threat.technique]]
122id = "T1112"
123name = "Modify Registry"
124reference = "https://attack.mitre.org/techniques/T1112/"
125
126[[rule.threat.technique]]
127id = "T1562"
128name = "Impair Defenses"
129reference = "https://attack.mitre.org/techniques/T1562/"
130
131
132[rule.threat.tactic]
133id = "TA0005"
134name = "Defense Evasion"
135reference = "https://attack.mitre.org/tactics/TA0005/"