Detectionmediumtest

Suspicious Download Via Certutil.EXE

Detects the execution of certutil with certain flags that allow the utility to download files.

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Launch
Florian Roth (Nextron Systems), Jonhnathan Ribeiro, oscd.community, Nasreddine Bencherchali (Nextron Systems)Created Wed Feb 15Updated Mon Dec 0119b08b1c-861d-4e75-a1ef-ea0c1baf202bwindows
Log Source
WindowsProcess Creation
ProductWindows← raw: windows
CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic
Detection Logic3 selectors
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_*
False Positives
Unknown

False positive likelihood has not been assessed. Additional context may be needed during triage.

Testing & Validation

Regression Tests

by SigmaHQ Team
Positive Detection Test1 matchevtx

Microsoft-Windows-Sysmon

Rule Metadata
Rule ID
19b08b1c-861d-4e75-a1ef-ea0c1baf202b
Status
test
Level
medium
Type
Detection
Created
Wed Feb 15
Modified
Mon Dec 01
Path
rules/windows/process_creation/proc_creation_win_certutil_download.yml
Raw Tags
attack.defense-evasionattack.t1027attack.command-and-controlattack.t1105
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