Detection rules › Sigma
Linux Shell Pipe to Shell
Detects suspicious process command line that starts with a shell that executes something and finally gets piped into another shell
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth | T1140 Deobfuscate/Decode Files or Information |
Event coverage
| Provider | Event |
|---|---|
| Sysmon-for-Linux | Event ID 1 |
Rule body yaml
title: Linux Shell Pipe to Shell
id: 880973f3-9708-491c-a77b-2a35a1921158
status: test
description: Detects suspicious process command line that starts with a shell that executes something and finally gets piped into another shell
references:
- Internal Research
author: Florian Roth (Nextron Systems)
date: 2022-03-14
modified: 2022-07-26
tags:
- attack.stealth
- attack.t1140
logsource:
product: linux
category: process_creation
detection:
selection:
CommandLine|startswith:
- 'sh -c '
- 'bash -c '
selection_exec:
- CommandLine|contains:
- '| bash '
- '| sh '
- '|bash '
- '|sh '
- CommandLine|endswith:
- '| bash'
- '| sh'
- '|bash'
- ' |sh'
condition: all of selection*
falsepositives:
- Legitimate software that uses these patterns
level: medium
Stages and Predicates
Stage 0: condition
all of selection*Stage 1: selection
selection:
CommandLine|startswith:
- 'sh -c '
- 'bash -c '
Stage 2: selection_exec
selection_exec:
- CommandLine|contains:
- '| bash '
- '| sh '
- '|bash '
- '|sh '
- CommandLine|endswith:
- '| bash'
- '| sh'
- '|bash'
- ' |sh'
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.
| Field | Kind | Values |
|---|---|---|
CommandLine | ends_with |
|
CommandLine | match |
|
CommandLine | starts_with |
|