WebDav Client Execution Via Rundll32.EXE — Sigma Rule

Rule metadata and linked tags

Author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research). Source status: test; severity: medium. Source dates: 2020-05-02 / 2023-09-18.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 8cea6ebbf93a2de605476f9974cc994027b73a0de74fe40906f98f6872edf41a

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: WebDav Client Execution Via Rundll32.EXE
id: 2dbd9d3d-9e27-42a8-b8df-f13825c6c3d5
status: test
description: |
    Detects "svchost.exe" spawning "rundll32.exe" with command arguments like "C:\windows\system32\davclnt.dll,DavSetCookie".
    This could be an indicator of exfiltration or use of WebDav to launch code (hosted on a WebDav server).
references:
    - https://github.com/OTRF/detection-hackathon-apt29/issues/17
    - https://github.com/OTRF/ThreatHunter-Playbook/blob/2d4257f630f4c9770f78d0c1df059f891ffc3fec/docs/evals/apt29/detections/7.B.4_C10730EA-6345-4934-AA0F-B0EFCA0C4BA6.md
author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research)
date: 2020-05-02
modified: 2023-09-18
tags:
    - attack.exfiltration
    - attack.t1048.003
logsource:
    category: process_creation
    product: windows
detection:
    selection_parent:
        ParentImage|endswith: '\svchost.exe'
    selection_img:
        - Image|endswith: '\rundll32.exe'
        - OriginalFileName: 'RUNDLL32.EXE'
    selection_cli:
        CommandLine|contains: 'C:\windows\system32\davclnt.dll,DavSetCookie'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://github.com/OTRF/detection-hackathon-apt29/issues/17
• https://github.com/OTRF/ThreatHunter-Playbook/blob/2d4257f630f4c9770f78d0c1df059f891ffc3fec/docs/evals/apt29/detections/7.B.4_C10730EA-6345-4934-AA0F-B0EFCA0C4BA6.md