Suspicious File Downloaded From Direct IP Via Certutil.EXE — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: high. Source dates: 2023-02-15 / 2025-12-01.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: e541e6f3383f9ab530f44b20dcee5046be96410ab9a48d78d3437ec85ea48fa0

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Suspicious File Downloaded From Direct IP Via Certutil.EXE
id: 13e6fe51-d478-4c7e-b0f2-6da9b400a829
related:
    - id: 19b08b1c-861d-4e75-a1ef-ea0c1baf202b # Direct IP download
      type: similar
    - id: 42a5f1e7-9603-4f6d-97ae-3f37d130d794 # File sharing download
      type: similar
status: test
description: Detects the execution of certutil with certain flags that allow the utility to download files from direct IPs.
references:
    - https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/certutil
    - https://forensicitguy.github.io/agenttesla-vba-certutil-download/
    - https://news.sophos.com/en-us/2021/04/13/compromised-exchange-server-hosting-cryptojacker-targeting-other-exchange-servers/
    - https://twitter.com/egre55/status/1087685529016193025
    - https://lolbas-project.github.io/lolbas/Binaries/Certutil/
    - https://twitter.com/_JohnHammond/status/1708910264261980634
    - https://www.hexacorn.com/blog/2020/08/23/certutil-one-more-gui-lolbin
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-02-15
modified: 2025-12-01
tags:
    - attack.stealth
    - attack.t1027
    - attack.command-and-control
    - attack.t1105
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\certutil.exe'
        - OriginalFileName: 'CertUtil.exe'
    selection_flags:
        CommandLine|contains:
            - 'urlcache '
            - 'verifyctl '
            - 'URL '
    selection_http:
        CommandLine|contains:
            - '://1'
            - '://2'
            - '://3'
            - '://4'
            - '://5'
            - '://6'
            - '://7'
            - '://8'
            - '://9'
    # filter_local_ips:
    #     # Note: Uncomment this filter if you want to exclude local IPs
    #     CommandLine|contains:
    #         - '://10.' # 10.0.0.0/8
    #         - '://192.168.' # 192.168.0.0/16
    #         - '://172.16.' # 172.16.0.0/12
    #         - '://172.17.'
    #         - '://172.18.'
    #         - '://172.19.'
    #         - '://172.20.'
    #         - '://172.21.'
    #         - '://172.22.'
    #         - '://172.23.'
    #         - '://172.24.'
    #         - '://172.25.'
    #         - '://172.26.'
    #         - '://172.27.'
    #         - '://172.28.'
    #         - '://172.29.'
    #         - '://172.30.'
    #         - '://172.31.'
    #         - '://127.' # 127.0.0.0/8
    #         - '://169.254.' # 169.254.0.0/16
    filter_main_seven_zip:
        CommandLine|contains: '://7-' # For https://7-zip.org/
    condition: all of selection_* and not 1 of filter_main_*
falsepositives:
    - Unknown
level: high
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_certutil_download_direct_ip/info.yml

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/certutil
• https://forensicitguy.github.io/agenttesla-vba-certutil-download/
• https://news.sophos.com/en-us/2021/04/13/compromised-exchange-server-hosting-cryptojacker-targeting-other-exchange-servers/
• https://twitter.com/egre55/status/1087685529016193025
• https://lolbas-project.github.io/lolbas/Binaries/Certutil/
• https://twitter.com/_JohnHammond/status/1708910264261980634
• https://www.hexacorn.com/blog/2020/08/23/certutil-one-more-gui-lolbin