Windows certutil.exe Used to Download Files via Suspicious Command-Line Flags

ATT&CK techniques

Defense Evasion → C2

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1027Obfuscated Files or Information
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1105Ingress Tool Transfer
Exfiltration
Impact

What it detects

This rule flags process creation events where certutil.exe is executed with command-line content consistent with downloading files (e.g., urlcache/verifyctl/URL) and with HTTP present in the command line. Attackers often use certutil.exe (a built-in Windows utility) to retrieve payloads or stage additional content while blending in with legitimate administrative tools. Detection relies on Windows process creation telemetry, including Image/OriginalFileName and CommandLine fields.

Reporting behind it

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Windows certutil.exe Used to Download Files via Suspicious Command-Line Flags

Pivot detection · T1105 · 9 related

Changelog

v2

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-certutil-exe-download-execution-with-url-cache-verify-flags-19b08b1c

title: Windows certutil.exe Used to Download Files via Suspicious Command-Line Flags
id: 406f276a-42ca-4709-bbdc-f0b4cd17ff04
related:
  - id: 13e6fe51-d478-4c7e-b0f2-6da9b400a829
    type: similar
  - id: 19b08b1c-861d-4e75-a1ef-ea0c1baf202b
    type: derived
status: test
description: This rule flags process creation events where certutil.exe is executed with command-line content consistent with downloading files (e.g., urlcache/verifyctl/URL) and with HTTP present in the command line. Attackers often use certutil.exe (a built-in Windows utility) to retrieve payloads or stage additional content while blending in with legitimate administrative tools. Detection relies on Windows process creation telemetry, including Image/OriginalFileName and CommandLine fields.
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://www.hexacorn.com/blog/2020/08/23/certutil-one-more-gui-lolbin
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_certutil_download.yml
author: Florian Roth (Nextron Systems), Jonhnathan Ribeiro, oscd.community, Nasreddine Bencherchali (Nextron Systems), Huntrule Team
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: http
  condition: all of selection_*
falsepositives:
  - Unknown
level: medium
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_certutil_download/info.yml
license: DRL-1.1

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