Potential GobRAT File Discovery Via Grep — Sigma Rule

Rule metadata and linked tags

Author: Joseliyo Sanchez, @Joseliyo_Jstnk. Source status: test; severity: high. Source dates: 2023-06-02 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 3e29e82c96e6422eb6dfb245390e5e281bc0bd87c0ca76ab1e85592aeffa1c2d

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: Potential GobRAT File Discovery Via Grep
id: e34cfa0c-0a50-4210-9cb3-5632d08eb041
status: test
description: Detects the use of grep to discover specific files created by the GobRAT malware
references:
    - https://blogs.jpcert.or.jp/en/2023/05/gobrat.html
    - https://www.virustotal.com/gui/file/60bcd645450e4c846238cf0e7226dc40c84c96eba99f6b2cffcd0ab4a391c8b3/detection
    - https://www.virustotal.com/gui/file/3e44c807a25a56f4068b5b8186eee5002eed6f26d665a8b791c472ad154585d1/detection
author: Joseliyo Sanchez, @Joseliyo_Jstnk
date: 2023-06-02
tags:
    - attack.discovery
    - attack.t1082
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        Image|endswith: '/grep'
        CommandLine|contains:
            - 'apached'
            - 'frpc'
            - 'sshd.sh'
            - 'zone.arm'
    condition: selection
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://blogs.jpcert.or.jp/en/2023/05/gobrat.html
• https://www.virustotal.com/gui/file/60bcd645450e4c846238cf0e7226dc40c84c96eba99f6b2cffcd0ab4a391c8b3/detection
• https://www.virustotal.com/gui/file/3e44c807a25a56f4068b5b8186eee5002eed6f26d665a8b791c472ad154585d1/detection