Suspicious RDP ActiveX Client Loaded

Last updated 5 months ago on 2025-03-20
Created 5 years ago on 2020-11-19

About

Identifies suspicious Image Loading of the Remote Desktop Services ActiveX Client (mstscax), this may indicate the presence of RDP lateral movement capability.
Tags
Domain: EndpointOS: WindowsUse Case: Threat DetectionTactic: Lateral MovementData Source: Elastic EndgameData Source: Elastic DefendData Source: SysmonLanguage: eql
Severity
medium
Risk Score
47
MITRE ATT&CK™

Lateral Movement (TA0008)(opens in a new tab or window)

License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
Event Correlation Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-endpoint.events.library-*winlogbeat-*logs-windows.sysmon_operational-*endgame-*
Related Integrations

endpoint(opens in a new tab or window)

windows(opens in a new tab or window)

Query
any where host.os.type == "windows" and
 (event.category : ("library", "driver") 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 : (
    "?:\\Windows\\System32\\mstsc.exe",
    "?:\\Windows\\SysWOW64\\mstsc.exe",
    "?:\\Windows\\System32\\vmconnect.exe",
    "?:\\Windows\\System32\\WindowsSandboxClient.exe",
    "?:\\Windows\\System32\\hvsirdpclient.exe"
  )

Install detection rules in Elastic Security

Detect Suspicious RDP ActiveX Client Loaded in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).