{"id":"894a8613-cf12-48b3-8e57-9085f54aa0c3","title":"Potential Base64 Encoded User-Agent","description":"Detects User Agent strings that end with an equal sign, which can be a sign of base64 encoding.","author":"Florian Roth (Nextron Systems), Brian Ingram (update)","status":"test","level":"medium","date":"2022-07-08","modified":"2023-05-04","tags":["attack.command-and-control","attack.t1071.001"],"technique_ids":["T1071.001"],"logsource":{"category":"proxy"},"falsepositives":["Unknown"],"references":["https://blogs.jpcert.or.jp/en/2022/07/yamabot.html","https://deviceatlas.com/blog/list-of-user-agent-strings#desktop"],"source_path":"rules/web/proxy_generic/proxy_ua_susp_base64.yml","source_sha256":"d909bdab6ebfb94ffc6159964798917aded622c0761539ddc9a328d3bfabf8a3","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/web/proxy_generic/proxy_ua_susp_base64.yml","license":"Detection Rule License 1.1","license_url":"https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md","yaml":"title: Potential Base64 Encoded User-Agent\nid: 894a8613-cf12-48b3-8e57-9085f54aa0c3\nrelated:\n    - id: d443095b-a221-4957-a2c4-cd1756c9b747\n      type: derived\nstatus: test\ndescription: Detects User Agent strings that end with an equal sign, which can be a sign of base64 encoding.\nreferences:\n    - https://blogs.jpcert.or.jp/en/2022/07/yamabot.html\n    - https://deviceatlas.com/blog/list-of-user-agent-strings#desktop\nauthor: Florian Roth (Nextron Systems), Brian Ingram (update)\ndate: 2022-07-08\nmodified: 2023-05-04\ntags:\n    - attack.command-and-control\n    - attack.t1071.001\nlogsource:\n    category: proxy\ndetection:\n    selection:\n        c-useragent|endswith: '='\n    condition: selection\nfalsepositives:\n    - Unknown\nlevel: medium\n","validation":"yaml_parsed_not_backend_compiled_or_live_validated","techniques":[{"key":"enterprise/T1071.001","id":"T1071.001","name":"Web Protocols","page":"techniques/enterprise/T1071.001/"}],"data_path":"data/detection-rules/894a8613-cf12-48b3-8e57-9085f54aa0c3.json","kind":"sigma"}