Suspicious RDP ActiveX Client Loaded

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Identifies suspicious Image Loading of the Remote Desktop Services ActiveX Client (mstscax), this may indicate the presence of RDP lateral movement capability.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*
  • winlogbeat-*
  • logs-windows.*

Severity: medium

Risk score: 47

Runs every: 5m

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

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Lateral Movement

Version: 101

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

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Rule query

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any where (event.category == "library" or (event.category == "process" and event.action : "Image loaded*")) and
 (dll.name : "mstscax.dll" or file.name : "mstscax.dll") and
   /* depending on noise in your env add here extra paths  */
  process.executable :
    (
    "C:\\Windows\\*",
    "C:\\Users\\Public\\*",
    "C:\\Users\\Default\\*",
    "C:\\Intel\\*",
    "C:\\PerfLogs\\*",
    "C:\\ProgramData\\*",
    "\\Device\\Mup\\*",
    "\\\\*"
    ) and
    /* add here FPs */
  not process.executable : ("C:\\Windows\\System32\\mstsc.exe", "C:\\Windows\\SysWOW64\\mstsc.exe")

Framework: MITRE ATT&CKTM