{"id":"4480827a-9799-4232-b2c4-ccc6c4e9e12b","title":"Suspicious CertReq Command to Download","description":"Detects a suspicious CertReq execution downloading a file.\nThis behavior is often used by attackers to download additional payloads or configuration files.\nCertreq is a built-in Windows utility used to request and retrieve certificates from a certification authority (CA). However, it can be abused by threat actors for malicious purposes.\n","author":"Christian Burkard (Nextron Systems)","status":"experimental","level":"high","date":"2021-11-24","modified":"2025-10-29","tags":["attack.command-and-control","attack.t1105"],"technique_ids":["T1105"],"logsource":{"category":"process_creation","product":"windows"},"falsepositives":["Unlikely"],"references":["https://lolbas-project.github.io/lolbas/Binaries/Certreq/"],"source_path":"rules/windows/process_creation/proc_creation_win_certreq_download.yml","source_sha256":"901342ae9cc2325212a2d66778210946c15f8c13a237bd23f3334760dd2962d5","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/windows/process_creation/proc_creation_win_certreq_download.yml","license":"Detection Rule License 1.1","license_url":"https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md","yaml":"title: Suspicious CertReq Command to Download\nid: 4480827a-9799-4232-b2c4-ccc6c4e9e12b\nstatus: experimental\ndescription: |\n    Detects a suspicious CertReq execution downloading a file.\n    This behavior is often used by attackers to download additional payloads or configuration files.\n    Certreq is a built-in Windows utility used to request and retrieve certificates from a certification authority (CA). However, it can be abused by threat actors for malicious purposes.\nreferences:\n    - https://lolbas-project.github.io/lolbas/Binaries/Certreq/\nauthor: Christian Burkard (Nextron Systems)\ndate: 2021-11-24\nmodified: 2025-10-29\ntags:\n    - attack.command-and-control\n    - attack.t1105\nlogsource:\n    category: process_creation\n    product: windows\ndetection:\n    selection_img:\n        - Image|endswith: '\\certreq.exe'\n        - OriginalFileName: 'CertReq.exe'\n    selection_cli_flag_post:\n        CommandLine|contains|windash: '-Post'\n    selection_cli_flag_config:\n        CommandLine|contains|windash: '-config'\n    selection_cli_http:\n        CommandLine|contains: 'http'\n    condition: all of selection_*\nfalsepositives:\n    - Unlikely\nlevel: high\n","validation":"yaml_parsed_not_backend_compiled_or_live_validated","techniques":[{"key":"enterprise/T1105","id":"T1105","name":"Ingress Tool Transfer","page":"techniques/enterprise/T1105/"}],"data_path":"data/detection-rules/4480827a-9799-4232-b2c4-ccc6c4e9e12b.json","kind":"sigma"}