{"id":"e32d4572-9826-4738-b651-95fa63747e8a","title":"Base64 Encoded PowerShell Command Detected","description":"Detects usage of the \"FromBase64String\" function in the commandline which is used to decode a base64 encoded string","author":"Florian Roth (Nextron Systems)","status":"test","level":"high","date":"2020-01-29","modified":"2023-01-26","tags":["attack.stealth","attack.t1027","attack.execution","attack.t1140","attack.t1059.001"],"technique_ids":["T1027","T1059.001","T1140"],"logsource":{"category":"process_creation","product":"windows"},"falsepositives":["Administrative script libraries"],"references":["https://gist.github.com/Neo23x0/6af876ee72b51676c82a2db8d2cd3639"],"source_path":"rules/windows/process_creation/proc_creation_win_powershell_frombase64string.yml","source_sha256":"66a4fcf31220cd42a87b6d713a2e23ee0ebc7b05e3ea0ffbf5b1de766a92e16b","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/windows/process_creation/proc_creation_win_powershell_frombase64string.yml","license":"Detection Rule License 1.1","license_url":"https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md","yaml":"title: Base64 Encoded PowerShell Command Detected\nid: e32d4572-9826-4738-b651-95fa63747e8a\nstatus: test\ndescription: Detects usage of the \"FromBase64String\" function in the commandline which is used to decode a base64 encoded string\nreferences:\n    - https://gist.github.com/Neo23x0/6af876ee72b51676c82a2db8d2cd3639\nauthor: Florian Roth (Nextron Systems)\ndate: 2020-01-29\nmodified: 2023-01-26\ntags:\n    - attack.stealth\n    - attack.t1027\n    - attack.execution\n    - attack.t1140\n    - attack.t1059.001\nlogsource:\n    category: process_creation\n    product: windows\ndetection:\n    selection:\n        CommandLine|contains: '::FromBase64String('\n    condition: selection\nfalsepositives:\n    - Administrative script libraries\nlevel: high\n","validation":"yaml_parsed_not_backend_compiled_or_live_validated","techniques":[{"key":"enterprise/T1027","id":"T1027","name":"Obfuscated Files or Information","page":"techniques/enterprise/T1027/"},{"key":"enterprise/T1059.001","id":"T1059.001","name":"PowerShell","page":"techniques/enterprise/T1059.001/"},{"key":"enterprise/T1140","id":"T1140","name":"Deobfuscate/Decode Files or Information","page":"techniques/enterprise/T1140/"}],"data_path":"data/detection-rules/e32d4572-9826-4738-b651-95fa63747e8a.json","kind":"sigma"}