Sigma Rule Library

Flush Iptables Ufw Chain

Detect use of iptables to flush all firewall rules, tables and chains and allow all network traffic

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Detection logic

selection_img

Image|endswith:
  - /iptables
  - /xtables-legacy-multi
  - /iptables-legacy-multi
  - /ip6tables
  - /ip6tables-legacy-multi

selection_params

CommandLine|contains:
  - -F
  - -Z
  - -X

selection_ufw

CommandLine|contains:
  - ufw-logging-deny
  - ufw-logging-allow
  - ufw6-logging-deny
  - ufw6-logging-allow

Condition

all of selection_*

Raw YAML

title: Flush Iptables Ufw Chain
id: 3be619f4-d9ec-4ea8-a173-18fdd01996ab
status: test
description: Detect use of iptables to flush all firewall rules, tables and chains and allow all network traffic
references:
    - https://blogs.blackberry.com/
    - https://www.cyberciti.biz/tips/linux-iptables-how-to-flush-all-rules.html
    - https://twitter.com/Joseliyo_Jstnk/status/1620131033474822144
author: Joseliyo Sanchez, @Joseliyo_Jstnk
date: 2023-01-18
tags:
    - attack.defense-impairment
    - attack.t1686
logsource:
    product: linux
    category: process_creation
detection:
    selection_img:
        Image|endswith:
            - '/iptables'
            - '/xtables-legacy-multi'
            - '/iptables-legacy-multi'
            - '/ip6tables'
            - '/ip6tables-legacy-multi'
    selection_params:
        CommandLine|contains:
            - '-F'
            - '-Z'
            - '-X'
    selection_ufw:
        CommandLine|contains:
            - 'ufw-logging-deny'
            - 'ufw-logging-allow'
            - 'ufw6-logging-deny'
            - 'ufw6-logging-allow'
            # - 'ufw-reject-output'
            # - 'ufw-track-inputt'
    condition: all of selection_*
falsepositives:
    - Network administrators
level: medium

False positives

  • Network administrators

References

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