Suspicious C2 Activities (via auditd)

title: Suspicious C2 Activities (via auditd)
id: 3476e63e-dfef-5e8a-a7ab-54d7f37a9a6c
status: stable
description: This rule detects anomalous activities as declared by Florian Roth in its 'Best Practice Auditd Configuration'. This includes the detection of the following commands; wget, curl, base64, nc, netcat, ncat, ssh, socat, wireshark, rawshark, rdesktop, nmap. These commands match a few methods from the tactics "Command and Control", including not exhaustively the following; Application Layer Protocol (T1071), Non-Application Layer Protocol (T1095), Data Encoding (T1132)
references:
    - https://github.com/Neo23x0/auditd
author: Huntrule Team
date: 2026-04-25
tags:
    - attack.command-and-control
    - attack.t1071
    - attack.t1095
    - attack.t1132
logsource:
    product: linux
    service: auditd
    definition: |
        Required auditd configuration:
        -w /usr/bin/wget -p x -k susp_activity
        -w /usr/bin/curl -p x -k susp_activity
        -w /usr/bin/base64 -p x -k susp_activity
        -w /bin/nc -p x -k susp_activity
        -w /bin/netcat -p x -k susp_activity
        -w /usr/bin/ncat -p x -k susp_activity
        -w /usr/bin/ss -p x -k susp_activity
        -w /usr/bin/netstat -p x -k susp_activity
        -w /usr/bin/ssh -p x -k susp_activity
        -w /usr/bin/scp -p x -k susp_activity
        -w /usr/bin/sftp -p x -k susp_activity
        -w /usr/bin/ftp -p x -k susp_activity
        -w /usr/bin/socat -p x -k susp_activity
        -w /usr/bin/wireshark -p x -k susp_activity
        -w /usr/bin/tshark -p x -k susp_activity
        -w /usr/bin/rawshark -p x -k susp_activity
        -w /usr/bin/rdesktop -p x -k susp_activity
        -w /usr/local/bin/rdesktop -p x -k susp_activity
        -w /usr/bin/wlfreerdp -p x -k susp_activity
        -w /usr/bin/xfreerdp -p x -k susp_activity
        -w /usr/local/bin/xfreerdp -p x -k susp_activity
        -w /usr/bin/nmap -p x -k susp_activity
        (via https://github.com/Neo23x0/auditd/blob/ddf2603dbc985f97538d102f13b4e4446b402bae/audit.rules#L336)
detection:
    selection:
        key: 'susp_activity'
    condition: selection
falsepositives:
    - Unknown
level: medium