Detection rules › Sigma

Crontab Enumeration

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

Detects usage of crontab to list the tasks of the user

MITRE ATT&CK coverage

TacticTechniques
DiscoveryT1007 System Service Discovery

Event coverage

Rule body yaml

title: Crontab Enumeration
id: 403ed92c-b7ec-4edd-9947-5b535ee12d46
status: test
description: Detects usage of crontab to list the tasks of the user
references:
    - https://blogs.jpcert.or.jp/en/2023/05/gobrat.html
    - https://jstnk9.github.io/jstnk9/research/GobRAT-Malware/
    - 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.t1007
logsource:
    product: linux
    category: process_creation
detection:
    selection:
        Image|endswith: '/crontab'
        CommandLine|contains: ' -l'
    condition: selection
falsepositives:
    - Legitimate use of crontab
level: low

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith: '/crontab'
    CommandLine|contains: ' -l'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
CommandLinematch
  • -l
Imageends_with
  • /crontab