sigmahighHunting

Suspicious Serv-U Process Pattern

Detects a suspicious process pattern which could be a sign of an exploited Serv-U service

MITRE ATT&CK

credential-access

Detection Query

selection:
  ParentImage|endswith: \Serv-U.exe
  Image|endswith:
    - \cmd.exe
    - \powershell.exe
    - \pwsh.exe
    - \wscript.exe
    - \cscript.exe
    - \sh.exe
    - \bash.exe
    - \schtasks.exe
    - \regsvr32.exe
    - \wmic.exe
    - \mshta.exe
    - \rundll32.exe
    - \msiexec.exe
    - \forfiles.exe
    - \scriptrunner.exe
condition: selection

Author

Florian Roth (Nextron Systems)

Created

2021-07-14

Data Sources

windowsProcess Creation Events

Platforms

windows

References

https://www.microsoft.com/security/blog/2021/07/13/microsoft-discovers-threat-actor-targeting-solarwinds-serv-u-software-with-0-day-exploit/

Tags

attack.credential-accessattack.t1555cve.2021-35211

Raw Content

title: Suspicious Serv-U Process Pattern
id: 58f4ea09-0fc2-4520-ba18-b85c540b0eaf
status: test
description: Detects a suspicious process pattern which could be a sign of an exploited Serv-U service
references:
    - https://www.microsoft.com/security/blog/2021/07/13/microsoft-discovers-threat-actor-targeting-solarwinds-serv-u-software-with-0-day-exploit/
author: Florian Roth (Nextron Systems)
date: 2021-07-14
modified: 2022-07-14
tags:
    - attack.credential-access
    - attack.t1555
    - cve.2021-35211
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\Serv-U.exe'
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
            - '\wscript.exe'
            - '\cscript.exe'
            - '\sh.exe'
            - '\bash.exe'
            - '\schtasks.exe'
            - '\regsvr32.exe'
            - '\wmic.exe'  # https://app.any.run/tasks/c903e9c8-0350-440c-8688-3881b556b8e0/
            - '\mshta.exe'
            - '\rundll32.exe'
            - '\msiexec.exe'
            - '\forfiles.exe'
            - '\scriptrunner.exe'
    condition: selection
falsepositives:
    - Legitimate uses in which users or programs use the SSH service of Serv-U for remote command execution
level: high