Suspicious External WebDAV Execution — Sigma Rule

Rule metadata and linked tags

Author: Ahmed Farouk. Source status: test; severity: high. Source dates: 2024-05-10 / not supplied.

{
  "category": "proxy"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: eddecfb0bf1104fe9ac85a02c031843b46186faa3dcbf9aab0d5121fa3f971f6

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: Suspicious External WebDAV Execution
id: 1ae64f96-72b6-48b3-ad3d-e71dff6c6398
related:
    - id: 4c55738d-72d8-490e-a2db-7969654e375f
      type: similar
status: test
description: |
    Detects executables launched from external WebDAV shares using the WebDAV Explorer integration, commonly seen in initial access campaigns.
references:
    - https://dear-territory-023.notion.site/WebDav-Share-Testing-e4950fa0c00149c3aa430d779b9b1d0f?pvs=4
    - https://micahbabinski.medium.com/search-ms-webdav-and-chill-99c5b23ac462
    - https://www.trendmicro.com/en_no/research/24/b/cve202421412-water-hydra-targets-traders-with-windows-defender-s.html
    - https://www.trellix.com/en-us/about/newsroom/stories/research/beyond-file-search-a-novel-method.html
author: Ahmed Farouk
date: 2024-05-10
tags:
    - attack.initial-access
    - attack.resource-development
    - attack.t1584
    - attack.t1566
logsource:
    category: proxy
detection:
    selection_webdav:
        c-useragent|startswith: 'Microsoft-WebDAV-MiniRedir/'
        cs-method: 'GET'
    selection_execution:
        c-uri|endswith:
            - '.7z'
            - '.bat'
            - '.dat'
            - '.cmd'
            - '.exe'
            - '.js'
            - '.lnk'
            - '.ps1'
            - '.rar'
            - '.url'
            - '.vbe'
            - '.vbs'
            - '.zip'
    filter_main_local_ips:
        dst_ip|cidr:
            - '127.0.0.0/8'
            - '10.0.0.0/8'
            - '172.16.0.0/12'
            - '192.168.0.0/16'
            - '169.254.0.0/16'
            - '::1/128'  # IPv6 loopback
            - 'fe80::/10'  # IPv6 link-local addresses
            - 'fc00::/7'  # IPv6 private addresses
    condition: all of selection_* and not 1 of filter_main_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://dear-territory-023.notion.site/WebDav-Share-Testing-e4950fa0c00149c3aa430d779b9b1d0f?pvs=4
• https://micahbabinski.medium.com/search-ms-webdav-and-chill-99c5b23ac462
• https://www.trendmicro.com/en_no/research/24/b/cve202421412-water-hydra-targets-traders-with-windows-defender-s.html
• https://www.trellix.com/en-us/about/newsroom/stories/research/beyond-file-search-a-novel-method.html