Sigma rule: Suspicious Chromium Browser Instance Executed With Custom Extension

Rule

Title

Suspicious Chromium Browser Instance Executed With Custom Extension

Status

test

Level

high

Author

Aedan Russell, frack113, X__Junior (Nextron Systems)

Date

2022-06-19

Modified

2023-11-28

File

rules/windows/process_creation/proc_creation_win_browsers_chromium_susp_load_extension.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects a suspicious process spawning a Chromium based browser process with the 'load-extension' flag to start an instance with a custom extension

Log source

product

windows

category

process_creation

Detection

selection:
    ParentImage|endswith:
        - '\cmd.exe'
        - '\cscript.exe'
        - '\mshta.exe'
        - '\powershell.exe'
        - '\pwsh.exe'
        - '\regsvr32.exe'
        - '\rundll32.exe'
        - '\wscript.exe'
    Image|endswith:
        - '\brave.exe'
        - '\chrome.exe'
        - '\msedge.exe'
        - '\opera.exe'
        - '\vivaldi.exe'
    CommandLine|contains: '--load-extension='
condition: selection

False positives (as the rule lists them)

• Unknown

Tags

• attack.persistence
• attack.t1176.001

MITRE ATT&CK ids this rule names

• T1176.001

Related rules

• 88d6e60c-759d-4ac1-a447-c0f1466c2d21 (similar)

References

• https://redcanary.com/blog/chromeloader/
• https://emkc.org/s/RJjuLa
• https://www.mandiant.com/resources/blog/lnk-between-browsers

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_browsers_chromium_susp_load_extension.yml