{"id":"e8314f79-564d-4f79-bc13-fbc0bf2660d8","title":"Potential PowerShell Obfuscation Using Character Join","description":"Detects specific techniques often seen used inside of PowerShell scripts to obfscuate Alias creation","author":"Nasreddine Bencherchali (Nextron Systems)","status":"test","level":"low","date":"2023-01-09","modified":"","tags":["attack.execution","attack.stealth","attack.t1027","attack.t1059.001"],"technique_ids":["T1027","T1059.001"],"logsource":{"product":"windows","category":"ps_script","definition":"Requirements: Script Block Logging must be enabled"},"falsepositives":["Unknown"],"references":["Internal Research"],"source_path":"rules/windows/powershell/powershell_script/posh_ps_susp_alias_obfscuation.yml","source_sha256":"e731d5ced65dc5f0c49785c98de883c65a07791ed776c4c4b7959a30d1d7bc76","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/windows/powershell/powershell_script/posh_ps_susp_alias_obfscuation.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 PowerShell Obfuscation Using Character Join\nid: e8314f79-564d-4f79-bc13-fbc0bf2660d8\nrelated:\n    - id: 96cd126d-f970-49c4-848a-da3a09f55c55\n      type: derived\nstatus: test\ndescription: Detects specific techniques often seen used inside of PowerShell scripts to obfscuate Alias creation\nreferences:\n    - Internal Research\nauthor: Nasreddine Bencherchali (Nextron Systems)\ndate: 2023-01-09\ntags:\n    - attack.execution\n    - attack.stealth\n    - attack.t1027\n    - attack.t1059.001\nlogsource:\n    product: windows\n    category: ps_script\n    definition: 'Requirements: Script Block Logging must be enabled'\ndetection:\n    selection:\n        # Example:\n        #   Set-Alias -Name Y -Value (-join(\"Ne\",\"w-O\",\"bje\",\"ct\"))\n        #   Set-Alias -Name X -Value (-join(\"Inv\",\"oke\",\"-\",\"Exp\",\"ression\"))\n        ScriptBlockText|contains|all:\n            - '-Alias' # For both \"New-Alias\" and \"Set-Alias\"\n            - ' -Value (-join('\n    condition: selection\nfalsepositives:\n    - Unknown\nlevel: low\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/"}],"data_path":"data/detection-rules/e8314f79-564d-4f79-bc13-fbc0bf2660d8.json","kind":"sigma"}