HackTool - EfsPotato Named Pipe Creation — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems). Source status: test; severity: high. Source dates: 2021-08-23 / 2023-12-21.

{
  "product": "windows",
  "category": "pipe_created",
  "definition": "Note that you have to configure logging for Named Pipe Events in Sysmon config (Event ID 17 and Event ID 18). The basic configuration is in popular sysmon configuration (https://github.com/SwiftOnSecurity/sysmon-config), but it is worth verifying. You can also use other repo, e.g. https://github.com/Neo23x0/sysmon-config, https://github.com/olafhartong/sysmon-modular. How to test detection? You can check powershell script from this site https://svch0st.medium.com/guide-to-named-pipes-and-hunting-for-cobalt-strike-pipes-dc46b2c5f575"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 21a07cf749ce126281b3091174d0b14f5dfeabb9d9ce5c4c8bd1a67cf479a52c

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: HackTool - EfsPotato Named Pipe Creation
id: 637f689e-b4a5-4a86-be0e-0100a0a33ba2
status: test
description: Detects the pattern of a pipe name as used by the hack tool EfsPotato
references:
    - https://twitter.com/SBousseaden/status/1429530155291193354?s=20
    - https://github.com/zcgonvh/EfsPotato
author: Florian Roth (Nextron Systems)
date: 2021-08-23
modified: 2023-12-21
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1055
logsource:
    product: windows
    category: pipe_created
    definition: 'Note that you have to configure logging for Named Pipe Events in Sysmon config (Event ID 17 and Event ID 18). The basic configuration is in popular sysmon configuration (https://github.com/SwiftOnSecurity/sysmon-config), but it is worth verifying. You can also use other repo, e.g. https://github.com/Neo23x0/sysmon-config, https://github.com/olafhartong/sysmon-modular. How to test detection? You can check powershell script from this site https://svch0st.medium.com/guide-to-named-pipes-and-hunting-for-cobalt-strike-pipes-dc46b2c5f575'
detection:
    selection:
        PipeName|contains:
            - '\pipe\'
            - '\pipe\srvsvc'  # more specific version (use only this one if the other causes too many false positives)
    filter_optional_ctx:
        PipeName|contains: '\CtxShare'
    filter_optional_default:
        PipeName|startswith: '\pipe\' # excludes pipes that start with \pipe\*
    condition: selection and not 1 of filter_optional_*
falsepositives:
    - \pipe\LOCAL\Monitorian # https://github.com/emoacht/Monitorian
level: high

Original YAML and metadata in JSON

False positives

• \pipe\LOCAL\Monitorian

Source references

• https://twitter.com/SBousseaden/status/1429530155291193354?s=20
• https://github.com/zcgonvh/EfsPotato