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Detection rules › Sigma

Potential GobRAT File Discovery Via Grep

Status
test
Severity
high
Log source
category process_creation, product linux
Author
Joseliyo Sanchez, @Joseliyo_Jstnk
Source
github.com/SigmaHQ/sigma

Detects the use of grep to discover specific files created by the GobRAT malware

MITRE ATT&CK coverage

TacticTechniques
Discovery

Telemetry coverage

PlatformRecord / event type
LinuxEvent ID 1: Process Create

Rule body

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

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith: '/grep'
    CommandLine|contains:
        - 'apached'
        - 'frpc'
        - 'sshd.sh'
        - 'zone.arm'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
CommandLinematch
  • apached
  • frpc
  • sshd.sh
  • zone.arm
field:"CommandLine" kind:match
Imageends_with
  • /grep
field:"Image" kind:ends_with value:"/grep"