Detection rules › Sigma
Decode Base64 Encoded Text
Detects usage of base64 utility to decode arbitrary base64-encoded text
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth | T1027 Obfuscated Files or Information |
Event coverage
| Provider | Event |
|---|---|
| Sysmon-for-Linux | Event ID 1 |
Rule body yaml
title: Decode Base64 Encoded Text
id: e2072cab-8c9a-459b-b63c-40ae79e27031
status: test
description: Detects usage of base64 utility to decode arbitrary base64-encoded text
references:
- https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1027/T1027.md
author: Daniil Yugoslavskiy, oscd.community
date: 2020-10-19
modified: 2021-11-27
tags:
- attack.stealth
- attack.t1027
logsource:
category: process_creation
product: linux
detection:
selection:
Image|endswith: '/base64'
CommandLine|contains: '-d' # Also covers "--decode"
condition: selection
falsepositives:
- Legitimate activities
level: low
Stages and Predicates
Stage 0: condition
selectionStage 1: selection
selection:
Image|endswith: '/base64'
CommandLine|contains: '-d'
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 |
|