{"id":"b7bc7038-638b-4ffd-880c-292c692209ef","title":"Certificate Request Export to Exchange Webserver","description":"Detects a write of an Exchange CSR to an untypical directory or with aspx name suffix which can be used to place a webshell","author":"Max Altgelt (Nextron Systems)","status":"test","level":"critical","date":"2021-08-23","modified":"2023-01-23","tags":["attack.persistence","attack.t1505.003"],"technique_ids":["T1505.003"],"logsource":{"service":"msexchange-management","product":"windows"},"falsepositives":["Unlikely"],"references":["https://twitter.com/GossiTheDog/status/1429175908905127938"],"source_path":"rules/windows/builtin/msexchange/win_exchange_proxyshell_certificate_generation.yml","source_sha256":"231164589966c7980323e9cc94bee77bbdf328c51f6bb4febcd4b1e4adadf60a","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/windows/builtin/msexchange/win_exchange_proxyshell_certificate_generation.yml","license":"Detection Rule License 1.1","license_url":"https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md","yaml":"title: Certificate Request Export to Exchange Webserver\nid: b7bc7038-638b-4ffd-880c-292c692209ef\nstatus: test\ndescription: Detects a write of an Exchange CSR to an untypical directory or with aspx name suffix which can be used to place a webshell\nreferences:\n    - https://twitter.com/GossiTheDog/status/1429175908905127938\nauthor: Max Altgelt (Nextron Systems)\ndate: 2021-08-23\nmodified: 2023-01-23\ntags:\n    - attack.persistence\n    - attack.t1505.003\nlogsource:\n    service: msexchange-management\n    product: windows\ndetection:\n    keywords_export_command:\n        '|all':\n            - 'New-ExchangeCertificate'\n            - ' -GenerateRequest'\n            - ' -BinaryEncoded'\n            - ' -RequestFile'\n    keywords_export_params:\n        - '\\\\\\\\localhost\\\\C$'\n        - '\\\\\\\\127.0.0.1\\\\C$'\n        - 'C:\\\\inetpub'\n        - '.aspx'\n    condition: keywords_export_command and keywords_export_params\nfalsepositives:\n    - Unlikely\nlevel: critical\n","validation":"yaml_parsed_not_backend_compiled_or_live_validated","techniques":[{"key":"enterprise/T1505.003","id":"T1505.003","name":"Web Shell","page":"techniques/enterprise/T1505.003/"}],"data_path":"data/detection-rules/b7bc7038-638b-4ffd-880c-292c692209ef.json","kind":"sigma"}