Remote XSL Script Execution via COM

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Identifies the execution of a hosted XSL script using the Microsoft.XMLDOM COM interface via Microsoft Office processes. This behavior may indicate adversarial activity to execute malicious JScript or VBScript on the system.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*

Severity: low

Risk score: 21

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Initial Access
  • Tactic: Defense Evasion
  • Data Source: Elastic Defend

Version: 2

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

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sequence with maxspan=1m
 [library where host.os.type == "windows" and dll.name : "msxml3.dll" and
  process.name : ("winword.exe", "excel.exe", "powerpnt.exe", "mspub.exe")] by process.entity_id
 [process where host.os.type == "windows" and event.action == "start" and
  process.parent.name : ("winword.exe", "excel.exe", "powerpnt.exe", "mspub.exe") and
  not process.executable :
        ("?:\\Windows\\System32\\WerFault.exe",
         "?:\\Windows\\SysWoW64\\WerFault.exe",
         "?:\\windows\\splwow64.exe",
         "?:\\Windows\\System32\\conhost.exe",
         "?:\\Program Files\\*.exe",
         "?:\\Program Files (x86)\\*exe")] by process.parent.entity_id

Framework: MITRE ATT&CKTM