Detection rules › Sigma
Suspicious Invocation of Shell via AWK - Linux
Detects the execution of "awk" or it's sibling commands, to invoke a shell using the system() function. This behavior is commonly associated with attempts to execute arbitrary commands or escalate privileges, potentially leading to unauthorized access or further exploitation.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | T1059 Command and Scripting Interpreter |
Event coverage
| Provider | Event |
|---|---|
| Sysmon-for-Linux | Event ID 1 |
Rule body yaml
title: Suspicious Invocation of Shell via AWK - Linux
id: 8c1a5675-cb85-452f-a298-b01b22a51856
status: test
description: |
Detects the execution of "awk" or it's sibling commands, to invoke a shell using the system() function.
This behavior is commonly associated with attempts to execute arbitrary commands or escalate privileges, potentially leading to unauthorized access or further exploitation.
references:
- https://gtfobins.github.io/gtfobins/awk/#shell
- https://gtfobins.github.io/gtfobins/gawk/#shell
- https://gtfobins.github.io/gtfobins/nawk/#shell
- https://gtfobins.github.io/gtfobins/mawk/#shell
author: Li Ling, Andy Parkidomo, Robert Rakowski, Blake Hartstein (Bloomberg L.P.)
date: 2024-09-02
tags:
- attack.execution
- attack.t1059
logsource:
category: process_creation
product: linux
detection:
selection_img:
Image|endswith:
- '/awk'
- '/gawk'
- '/mawk'
- '/nawk'
CommandLine|contains: 'BEGIN {system'
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:
- '/awk'
- '/gawk'
- '/mawk'
- '/nawk'
CommandLine|contains: 'BEGIN {system'
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.
| Field | Kind | Values |
|---|---|---|
CommandLine | match |
|
Image | ends_with |
|