Suspicious RDP ActiveX Client Loaded

Elastic Stack Serverless Security

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 (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)

Maximum alerts per execution: 100

References:

• https://posts.specterops.io/revisiting-remote-desktop-lateral-movement-8fb905cb46c3

Tags:

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

Version: 6

Rule authors:

• Elastic

Rule license: Elastic License v2

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

• Tactic:

  • Name: Lateral Movement
  • ID: TA0008
  • Reference URL: https://attack.mitre.org/tactics/TA0008/

• Technique:

  • Name: Remote Services
  • ID: T1021
  • Reference URL: https://attack.mitre.org/techniques/T1021/