{"id":"f6de9536-0441-4b3f-a646-f4e00f300ffd","title":"Weak Encryption Enabled and Kerberoast","description":"Detects scenario where weak encryption is enabled for a user profile which could be used for hash/password cracking.","author":"@neu5ron","status":"test","level":"high","date":"2017-07-30","modified":"2021-11-27","tags":["attack.defense-impairment","attack.t1685"],"technique_ids":["T1685"],"logsource":{"product":"windows","service":"security","definition":"Requirements: Audit Policy : Account Management > Audit User Account Management, Group Policy : Computer Configuration\\Windows Settings\\Security Settings\\Advanced Audit Policy Configuration\\Audit Policies\\Account Management\\Audit User Account Management"},"falsepositives":["Unknown"],"references":["https://adsecurity.org/?p=2053","https://blog.harmj0y.net/redteaming/another-word-on-delegation/"],"source_path":"rules/windows/builtin/security/win_security_alert_enable_weak_encryption.yml","source_sha256":"09fcd86ecffb421cb0df3175b4b5762e50e40ce9d71f6e56265cbf54b1d7728f","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/windows/builtin/security/win_security_alert_enable_weak_encryption.yml","license":"Detection Rule License 1.1","license_url":"https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md","yaml":"title: Weak Encryption Enabled and Kerberoast\nid: f6de9536-0441-4b3f-a646-f4e00f300ffd\nstatus: test\ndescription: Detects scenario where weak encryption is enabled for a user profile which could be used for hash/password cracking.\nreferences:\n    - https://adsecurity.org/?p=2053\n    - https://blog.harmj0y.net/redteaming/another-word-on-delegation/\nauthor: '@neu5ron'\ndate: 2017-07-30\nmodified: 2021-11-27\ntags:\n    - attack.defense-impairment\n    - attack.t1685\nlogsource:\n    product: windows\n    service: security\n    definition: 'Requirements: Audit Policy : Account Management > Audit User Account Management, Group Policy : Computer Configuration\\Windows Settings\\Security Settings\\Advanced Audit Policy Configuration\\Audit Policies\\Account Management\\Audit User Account Management'\ndetection:\n    selection:\n        EventID: 4738\n    # According to Microsoft, the bit values are listed here: https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/auditing/event-4720\n    # However, that seems to be a simple copy from https://learn.microsoft.com/en-us/troubleshoot/windows-server/active-directory/useraccountcontrol-manipulate-account-properties\n    # and the actual flags that are used are quite different and, unfortunately, not documented.\n    # https://github.com/mdecrevoisier/EVTX-to-MITRE-Attack/ contains a number of EVTX files with relevant events, which can be used to extract\n    # the following values.\n    olduac_des: # 0x8000\n        OldUacValue|endswith:\n            - 8???\n            - 9???\n            - A???\n            - B???\n            - C???\n            - D???\n            - E???\n            - F???\n    newuac_des:\n        NewUacValue|endswith:\n            - 8???\n            - 9???\n            - A???\n            - B???\n            - C???\n            - D???\n            - E???\n            - F???\n    olduac_preauth: # 0x10000\n        OldUacValue|endswith:\n            - 1????\n            - 3????\n            - 5????\n            - 7????\n            - 9????\n            - B????\n            - D????\n            - F????\n    newuac_preauth:\n        NewUacValue|endswith:\n            - 1????\n            - 3????\n            - 5????\n            - 7????\n            - 9????\n            - B????\n            - D????\n            - F????\n    olduac_encrypted: # 0x800\n        OldUacValue|endswith:\n            - 8??\n            - 9??\n            - A??\n            - B??\n            - C??\n            - D??\n            - E??\n            - F??\n    newuac_encrypted:\n        NewUacValue|endswith:\n            - 8??\n            - 9??\n            - A??\n            - B??\n            - C??\n            - D??\n            - E??\n            - F??\n    condition: selection and ((newuac_des and not olduac_des) or (newuac_preauth and not olduac_preauth) or (newuac_encrypted and not olduac_encrypted))\nfalsepositives:\n    - Unknown\nlevel: high\n","validation":"yaml_parsed_not_backend_compiled_or_live_validated","techniques":[{"key":"enterprise/T1685","id":"T1685","name":"Disable or Modify Tools","page":"techniques/enterprise/T1685/"}],"data_path":"data/detection-rules/f6de9536-0441-4b3f-a646-f4e00f300ffd.json","kind":"sigma"}