Detectionmediumtest

Potential Suspicious Change To Sensitive/Critical Files

Detects changes of sensitive and critical files. Monitors files that you don't expect to change without planning on Linux system.

Convert In Phoenix Studio

Open this Sigma rule in the converter with the YAML preloaded and ready for backend selection.

Launch

Created Tue May 3086157017-c2b1-4d4a-8c33-93b8e67e4af4linux

Log Source

LinuxProcess Creation

ProductLinux← raw: linux

CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic

detection:
    selection_img_1:
        Image|endswith:
            - '/cat'
            - '/echo'
            - '/grep'
            - '/head'
            - '/more'
            - '/tail'
        CommandLine|contains: '>'
    selection_img_2:
        Image|endswith:
            - '/emacs'
            - '/nano'
            - '/sed'
            - '/vi'
            - '/vim'
    selection_paths:
        CommandLine|contains:
            - '/bin/login'
            - '/bin/passwd'
            - '/boot/'
            - '/etc/*.conf'
            - '/etc/cron.' # Covers different cron config files "daily", "hourly", etc.
            - '/etc/crontab'
            - '/etc/hosts'
            - '/etc/init.d'
            - '/etc/sudoers'
            - '/opt/bin/'
            - '/sbin' # Covers: '/opt/sbin', '/usr/local/sbin/', '/usr/sbin/'
            - '/usr/bin/'
            - '/usr/local/bin/'
    condition: 1 of selection_img_* and selection_paths