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Suspicious CertReq Command to Download

Detects a suspicious CertReq execution downloading a file. This behavior is often used by attackers to download additional payloads or configuration files. 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.

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ATT&CK techniques

T1105

Rule sourcerules/windows/process_creation/proc_creation_win_certreq_download.yml

title: Suspicious CertReq Command to Download
id: 4480827a-9799-4232-b2c4-ccc6c4e9e12b
status: experimental
description: |
    Detects a suspicious CertReq execution downloading a file.
    This behavior is often used by attackers to download additional payloads or configuration files.
    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.
references:
    - https://lolbas-project.github.io/lolbas/Binaries/Certreq/
author: Christian Burkard (Nextron Systems)
date: 2021-11-24
modified: 2025-10-29
tags:
    - attack.command-and-control
    - attack.t1105
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\certreq.exe'
        - OriginalFileName: 'CertReq.exe'
    selection_cli_flag_post:
        CommandLine|contains|windash: '-Post'
    selection_cli_flag_config:
        CommandLine|contains|windash: '-config'
    selection_cli_http:
        CommandLine|contains: 'http'
    condition: all of selection_*
falsepositives:
    - Unlikely
level: high