SigmaHQ/rules/proxy/proxy_ua_suspicious.yml
2019-02-05 14:35:23 +01:00

36 lines
1.2 KiB
YAML

title: Suspicious User Agent
status: experimental
description: Detects suspicious malformed user agent strings in proxy logs
references:
- https://github.com/fastly/waf_testbed/blob/master/templates/default/scanners-user-agents.data.erb
author: Florian Roth
logsource:
category: proxy
detection:
selection:
UserAgent:
# Badly scripted UA
- 'user-agent' # User-Agent: User-Agent:
- '* (compatible;MSIE *' # typical typo - missing space
- '*.0;Windows NT *' # typical typo - missing space
- 'Mozilla/3.0 *'
- 'Mozilla/2.0 *'
- 'Mozilla/1.0 *'
- 'Mozilla *' # missing slash
- ' Mozilla/*' # leading space
- 'Mozila/*' # single 'l'
- '_'
- 'CertUtil URL Agent' # https://twitter.com/stvemillertime/status/985150675527974912
- 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:60.0)' # CobaltStrike Beacon https://unit42.paloaltonetworks.com/tracking-oceanlotus-new-downloader-kerrdown/
falsepositives:
UserAgent:
- 'Mozilla/3.0 * Acrobat *' # Acrobat with linked content
condition: selection and not falsepositives
fields:
- ClientIP
- URL
- UserAgent
falsepositives:
- Unknown
level: high