Sigma rule: Suspicious Non-Browser Network Communication With Google API

Rule

Title

Suspicious Non-Browser Network Communication With Google API

Status

experimental

Level

medium

Author

Gavin Knapp

Date

2023-05-01

Modified

2025-02-22

File

rules/windows/network_connection/net_connection_win_domain_google_api_non_browser_access.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects a non-browser process interacting with the Google API which could indicate the use of a covert C2 such as Google Sheet C2 (GC2-sheet)

Log source

product

windows

category

network_connection

Detection

selection:
    DestinationHostname|contains:
        # Note: Please add additional google API related domains that might be abused.
        - 'drive.googleapis.com'
        - 'oauth2.googleapis.com'
        - 'sheets.googleapis.com'
        - 'www.googleapis.com'
filter_optional_brave:
    Image|endswith: '\brave.exe'
filter_optional_chrome:
    Image|endswith:
        - ':\Program Files\Google\Chrome\Application\chrome.exe'
        - ':\Program Files (x86)\Google\Chrome\Application\chrome.exe'
filter_optional_google_drive:
    Image|contains: ':\Program Files\Google\Drive File Stream\'
    Image|endswith: '\GoogleDriveFS.exe'
filter_optional_firefox:
    Image|endswith:
        - ':\Program Files\Mozilla Firefox\firefox.exe'
        - ':\Program Files (x86)\Mozilla Firefox\firefox.exe'
filter_optional_ie:
    Image|endswith:
        - ':\Program Files (x86)\Internet Explorer\iexplore.exe'
        - ':\Program Files\Internet Explorer\iexplore.exe'
filter_optional_maxthon:
    Image|endswith: '\maxthon.exe'
filter_optional_edge_1:
    - Image|contains: ':\Program Files (x86)\Microsoft\EdgeWebView\Application\'
    - Image|endswith:
          - ':\Program Files (x86)\Microsoft\Edge\Application\msedge.exe'
          - ':\Program Files\Microsoft\Edge\Application\msedge.exe'
          - '\WindowsApps\MicrosoftEdge.exe'
filter_optional_edge_2:
    Image|contains:
        - ':\Program Files (x86)\Microsoft\EdgeCore\'
        - ':\Program Files\Microsoft\EdgeCore\'
    Image|endswith:
        - '\msedge.exe'
        - '\msedgewebview2.exe'
filter_optional_opera:
    Image|endswith: '\opera.exe'
filter_optional_safari:
    Image|endswith: '\safari.exe'
filter_optional_seamonkey:
    Image|endswith: '\seamonkey.exe'
filter_optional_vivaldi:
    Image|endswith: '\vivaldi.exe'
filter_optional_whale:
    Image|endswith: '\whale.exe'
filter_optional_googleupdate:
    Image|endswith: '\GoogleUpdate.exe'
filter_optional_outlook_exe:
    Image|endswith: '\outlook.exe'
filter_main_null:
    Image: null
filter_main_empty:
    Image: ''
condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*

False positives (as the rule lists them)

• Legitimate applications communicating with the "googleapis.com" endpoints that are not already in the exclusion list. This is environmental dependent and requires further testing and tuning.

Tags

• attack.command-and-control
• attack.t1102

MITRE ATT&CK ids this rule names

• T1102

References

• https://github.com/looCiprian/GC2-sheet
• https://youtu.be/n2dFlSaBBKo
• https://services.google.com/fh/files/blogs/gcat_threathorizons_full_apr2023.pdf
• https://www.tanium.com/blog/apt41-deploys-google-gc2-for-attacks-cyber-threat-intelligence-roundup/
• https://www.bleepingcomputer.com/news/security/hackers-abuse-google-command-and-control-red-team-tool-in-attacks/

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/network_connection/net_connection_win_domain_google_api_non_browser_access.yml