Detection rules › Sigma

Suspicious Non-Browser Network Communication With Google API

Severity
medium
Author
Gavin Knapp
Source
upstream

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)

MITRE ATT&CK coverage

TacticTechniques
Command & ControlT1102 Web Service

Event coverage

ProviderEvent IDTitle
Sysmon3Network connection

Stages and Predicates

Stage 1: selection

or:
DestinationHostname|contains: drive.googleapis.com
DestinationHostname|contains: oauth2.googleapis.com
DestinationHostname|contains: sheets.googleapis.com
DestinationHostname|contains: www.googleapis.com

Stage 2: not 1 of filter_main_*

or:
Image: ''
Image: null

Stage 3: not 1 of filter_optional_*

or:
or:
Image|endswith: '\msedge.exe'
Image|endswith: '\msedgewebview2.exe'
or:
Image|contains: ':\Program Files (x86)\Microsoft\EdgeCore\'
Image|contains: ':\Program Files\Microsoft\EdgeCore\'
Image|endswith: '\GoogleDriveFS.exe'
Image|contains: ':\Program Files\Google\Drive File Stream\'
Image|endswith: ':\Program Files (x86)\Google\Chrome\Application\chrome.exe'
Image|endswith: ':\Program Files (x86)\Internet Explorer\iexplore.exe'
Image|endswith: ':\Program Files (x86)\Microsoft\Edge\Application\msedge.exe'
Image|endswith: ':\Program Files (x86)\Mozilla Firefox\firefox.exe'
Image|endswith: ':\Program Files\Google\Chrome\Application\chrome.exe'
Image|endswith: ':\Program Files\Internet Explorer\iexplore.exe'
Image|endswith: ':\Program Files\Microsoft\Edge\Application\msedge.exe'
Image|endswith: ':\Program Files\Mozilla Firefox\firefox.exe'
Image|endswith: '\GoogleUpdate.exe'
Image|endswith: '\WindowsApps\MicrosoftEdge.exe'
Image|endswith: '\brave.exe'
Image|endswith: '\maxthon.exe'
Image|endswith: '\opera.exe'
Image|endswith: '\outlook.exe'
Image|endswith: '\safari.exe'
Image|endswith: '\seamonkey.exe'
Image|endswith: '\vivaldi.exe'
Image|endswith: '\whale.exe'
Image|contains: ':\Program Files (x86)\Microsoft\EdgeWebView\Application\'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
DestinationHostnamematch
  • drive.googleapis.com
  • oauth2.googleapis.com
  • sheets.googleapis.com
  • www.googleapis.com
Imageends_with
  • :\Program Files (x86)\Google\Chrome\Application\chrome.exe
  • :\Program Files (x86)\Internet Explorer\iexplore.exe
  • :\Program Files (x86)\Microsoft\Edge\Application\msedge.exe
  • :\Program Files (x86)\Mozilla Firefox\firefox.exe
  • :\Program Files\Google\Chrome\Application\chrome.exe
  • :\Program Files\Internet Explorer\iexplore.exe
  • :\Program Files\Microsoft\Edge\Application\msedge.exe
  • :\Program Files\Mozilla Firefox\firefox.exe
  • \GoogleDriveFS.exe
  • \GoogleUpdate.exe
  • \WindowsApps\MicrosoftEdge.exe corpus 12 (sigma 12)
  • \brave.exe corpus 20 (sigma 20)
  • \maxthon.exe corpus 13 (sigma 13)
  • \msedge.exe corpus 22 (sigma 22)
  • \msedgewebview2.exe corpus 15 (sigma 15)
  • \opera.exe corpus 21 (sigma 21)
  • \outlook.exe corpus 16 (sigma 16)
  • \safari.exe corpus 12 (sigma 12)
  • \seamonkey.exe corpus 13 (sigma 13)
  • \vivaldi.exe corpus 19 (sigma 19)
  • \whale.exe corpus 12 (sigma 12)
Imagematch
  • :\Program Files (x86)\Microsoft\EdgeCore\
  • :\Program Files (x86)\Microsoft\EdgeWebView\Application\
  • :\Program Files\Google\Drive File Stream\
  • :\Program Files\Microsoft\EdgeCore\