Detection rules › Sigma

Shell Execution via Find - Linux

Status
test
Severity
high
Log source
product linux, category process_creation
Author
Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
Source
github.com/SigmaHQ/sigma

Detects the use of the find command to execute a shell. Such behavior may be associated with privilege escalation, unauthorized command execution, or exploitation attempt.

MITRE ATT&CK coverage

TacticTechniques
DiscoveryT1083 File and Directory Discovery

Event coverage

Rule body yaml

title: Shell Execution via Find - Linux
id: 6adfbf8f-52be-4444-9bac-81b539624146
status: test
description: |
    Detects the use of the find command to execute a shell. Such behavior may be associated with privilege escalation, unauthorized command execution, or exploitation attempt.
references:
    - https://gtfobins.github.io/gtfobins/find/#shell
    - https://www.elastic.co/guide/en/security/current/linux-restricted-shell-breakout-via-linux-binary-s.html
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
date: 2024-09-02
tags:
    - attack.discovery
    - attack.t1083
logsource:
    category: process_creation
    product: linux
detection:
    selection_img:
        Image|endswith: '/find'
        CommandLine|contains|all:
            - ' . '
            - '-exec'
    selection_cli:
        CommandLine|contains:
            - '/bin/bash'
            - '/bin/dash'
            - '/bin/fish'
            - '/bin/sh'
            - '/bin/zsh'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    Image|endswith: '/find'
    CommandLine|contains|all:
        - ' . '
        - '-exec'

Stage 2: selection_cli

selection_cli:
    CommandLine|contains:
        - '/bin/bash'
        - '/bin/dash'
        - '/bin/fish'
        - '/bin/sh'
        - '/bin/zsh'

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
  • .
  • -exec
  • /bin/bash
  • /bin/dash
  • /bin/fish
  • /bin/sh
  • /bin/zsh
Imageends_with
  • /find