frack113
28 lines
736 B
YAML
28 lines
736 B
YAML
title: Suspicious Base64 User Agent
|
|
id: 894a8613-cf12-48b3-8e57-9085f54aa0c3
|
|
status: experimental
|
|
description: Detects suspicious User Agent strings that end with an equal sign, which can be a sign of base64 encoded values used as User Agent string
|
|
references:
|
|
- https://blogs.jpcert.or.jp/en/2022/07/yamabot.html
|
|
author: Florian Roth
|
|
date: 2022/07/08
|
|
modified: 2022/11/27
|
|
tags:
|
|
- attack.command_and_control
|
|
- attack.t1071.001
|
|
logsource:
|
|
category: proxy
|
|
detection:
|
|
selection:
|
|
c-useragent|endswith:
|
|
- '='
|
|
- 'TW96aWxsY' # base64 encoded Mozilla/ as used by YamaBot
|
|
condition: selection
|
|
fields:
|
|
- ClientIP
|
|
- c-uri
|
|
- c-useragent
|
|
falsepositives:
|
|
- Unknown
|
|
level: high
|