Suspicious RDP ActiveX Client Loaded

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: 4

Rule authors:

• Elastic

Rule license: Elastic License v2

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define event.ingested and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate event.ingested to @timestamp for this rule to work.

library where dll.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/