Suspicious Activity in Shell Commands — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems). Source status: test; severity: high. Source dates: 2017-08-21 / 2021-11-27.

{
  "product": "linux"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 6958c20c0ba481e5fd34cd4a7ee85302a685cba63e985c21f58d5a34101c2663

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: Suspicious Activity in Shell Commands
id: 2aa1440c-9ae9-4d92-84a7-a9e5f5e31695
status: test
description: Detects suspicious shell commands used in various exploit codes (see references)
references:
    - https://web.archive.org/web/20170319121015/http://www.threatgeek.com/2017/03/widespread-exploitation-attempts-using-cve-2017-5638.html
    - https://github.com/rapid7/metasploit-framework/blob/eb6535009f5fdafa954525687f09294918b5398d/modules/exploits/multi/http/struts_code_exec_exception_delegator.rb
    - http://pastebin.com/FtygZ1cg
    - https://artkond.com/2017/03/23/pivoting-guide/
author: Florian Roth (Nextron Systems)
date: 2017-08-21
modified: 2021-11-27
tags:
    - attack.execution
    - attack.t1059.004
logsource:
    product: linux
detection:
    keywords:
        # Generic suspicious commands
        - 'wget * - http* | perl'
        - 'wget * - http* | sh'
        - 'wget * - http* | bash'
        - 'python -m SimpleHTTPServer'
        - '-m http.server'      # Python 3
        - 'import pty; pty.spawn*'
        - 'socat exec:*'
        - 'socat -O /tmp/*'
        - 'socat tcp-connect*'
        - '*echo binary >>*'
        # Malware
        - '*wget *; chmod +x*'
        - '*wget *; chmod 777 *'
        - '*cd /tmp || cd /var/run || cd /mnt*'
        # Apache Struts in-the-wild exploit codes
        - '*stop;service iptables stop;*'
        - '*stop;SuSEfirewall2 stop;*'
        - 'chmod 777 2020*'
        - '*>>/etc/rc.local'
        # Metasploit framework exploit codes
        - '*base64 -d /tmp/*'
        - '* | base64 -d *'
        - '*/chmod u+s *'
        - '*chmod +s /tmp/*'
        - '*chmod u+s /tmp/*'
        - '* /tmp/haxhax*'
        - '* /tmp/ns_sploit*'
        - 'nc -l -p *'
        - 'cp /bin/ksh *'
        - 'cp /bin/sh *'
        - '* /tmp/*.b64 *'
        - '*/tmp/ysocereal.jar*'
        - '*/tmp/x *'
        - '*; chmod +x /tmp/*'
        - '*;chmod +x /tmp/*'
    condition: keywords
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://web.archive.org/web/20170319121015/http://www.threatgeek.com/2017/03/widespread-exploitation-attempts-using-cve-2017-5638.html
• https://github.com/rapid7/metasploit-framework/blob/eb6535009f5fdafa954525687f09294918b5398d/modules/exploits/multi/http/struts_code_exec_exception_delegator.rb
• http://pastebin.com/FtygZ1cg
• https://artkond.com/2017/03/23/pivoting-guide/