Windows: Potential Process Injection via Msra.exe Spawning Suspicious Child Processes

Flags Msra.exe spawning suspicious tools that may indicate process injection or post-exploitation activity on Windows.

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title: "Windows: Potential Process Injection via Msra.exe Spawning Suspicious Child Processes"
id: a4dc5806-2807-4559-988c-ff2ac5e056da
status: test
description: This rule identifies potential process injection activity by flagging when Msra.exe spawns child processes associated with command execution, discovery, and system interrogation. Attackers may use Msra.exe to blend into legitimate remote assistance activity while running additional tooling through spawned binaries. The detection relies on process creation telemetry capturing parent process image and command line, along with the spawned child process image names.
references:
  - https://www.microsoft.com/security/blog/2021/12/09/a-closer-look-at-qakbots-latest-building-blocks-and-how-to-knock-them-down/
  - https://www.fortinet.com/content/dam/fortinet/assets/analyst-reports/ar-qakbot.pdf
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_msra_process_injection.yml
author: Alexander McDonald, Huntrule Team
date: 2022-06-24
modified: 2023-02-03
tags:
  - attack.privilege-escalation
  - attack.stealth
  - attack.t1055
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    ParentImage|endswith: \msra.exe
    ParentCommandLine|endswith: msra.exe
    Image|endswith:
      - \arp.exe
      - \cmd.exe
      - \net.exe
      - \netstat.exe
      - \nslookup.exe
      - \route.exe
      - \schtasks.exe
      - \whoami.exe
  condition: selection
falsepositives:
  - Legitimate use of Msra.exe
level: high
license: DRL-1.1
related:
  - id: 744a188b-0415-4792-896f-11ddb0588dbc
    type: derived

What it detects

This rule identifies potential process injection activity by flagging when Msra.exe spawns child processes associated with command execution, discovery, and system interrogation. Attackers may use Msra.exe to blend into legitimate remote assistance activity while running additional tooling through spawned binaries. The detection relies on process creation telemetry capturing parent process image and command line, along with the spawned child process image names.

Known false positives

Legitimate use of Msra.exe

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.