Nasreddine Bencherchali
598d29f811
chore: change tags, date, modified fields to comply with v2 of the Sigma spec. chore: update the related type from `obsoletes` to `obsolete`. chore: update local json schema to the latest version.
28 lines
976 B
YAML
28 lines
976 B
YAML
title: Suspicious Base64 Encoded User-Agent
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id: d443095b-a221-4957-a2c4-cd1756c9b747
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related:
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- id: 894a8613-cf12-48b3-8e57-9085f54aa0c3
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type: derived
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status: test
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description: Detects suspicious encoded User-Agent strings, as seen used by some malware.
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references:
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- https://deviceatlas.com/blog/list-of-user-agent-strings#desktop
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author: Nasreddine Bencherchali (Nextron Systems)
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date: 2023-05-04
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tags:
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- attack.command-and-control
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- attack.t1071.001
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logsource:
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category: proxy
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detection:
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selection:
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c-useragent|startswith:
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- 'Q2hyb21l' # Chrome Encoded with offset to not include padding
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- 'QXBwbGVXZWJLaX' # AppleWebKit Encoded with offset to not include padding
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- 'RGFsdmlr' # Dalvik Encoded with offset to not include padding
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- 'TW96aWxsY' # Mozilla Encoded with offset to not include padding (as used by YamaBot)
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condition: selection
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falsepositives:
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- Unknown
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level: medium
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