Suspicious Non-Browser Network Communication With Google API
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)
Sigma rule (View on GitHub)
1title: Suspicious Non-Browser Network Communication With Google API
2id: 7e9cf7b6-e827-11ed-a05b-0242ac120003
3status: experimental
4description: |
5 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)
6references:
7 - https://github.com/looCiprian/GC2-sheet
8 - https://youtu.be/n2dFlSaBBKo
9 - https://services.google.com/fh/files/blogs/gcat_threathorizons_full_apr2023.pdf
10 - https://www.tanium.com/blog/apt41-deploys-google-gc2-for-attacks-cyber-threat-intelligence-roundup/
11 - https://www.bleepingcomputer.com/news/security/hackers-abuse-google-command-and-control-red-team-tool-in-attacks/
12author: Gavin Knapp
13date: 2023-05-01
14modified: 2024-07-16
15tags:
16 - attack.command-and-control
17 - attack.t1102
18logsource:
19 product: windows
20 category: network_connection
21detection:
22 selection:
23 DestinationHostname|contains:
24 # Note: Please add additional google API related domains that might be abused.
25 - 'drive.googleapis.com'
26 - 'oauth2.googleapis.com'
27 - 'sheets.googleapis.com'
28 - 'www.googleapis.com'
29 filter_optional_brave:
30 Image|endswith: '\brave.exe'
31 filter_optional_chrome:
32 Image|endswith:
33 - ':\Program Files\Google\Chrome\Application\chrome.exe'
34 - ':\Program Files (x86)\Google\Chrome\Application\chrome.exe'
35 filter_optional_google_drive:
36 Image|contains: ':\Program Files\Google\Drive File Stream\'
37 Image|endswith: '\GoogleDriveFS.exe'
38 filter_optional_firefox:
39 Image|endswith:
40 - ':\Program Files\Mozilla Firefox\firefox.exe'
41 - ':\Program Files (x86)\Mozilla Firefox\firefox.exe'
42 filter_optional_ie:
43 Image|endswith:
44 - ':\Program Files (x86)\Internet Explorer\iexplore.exe'
45 - ':\Program Files\Internet Explorer\iexplore.exe'
46 filter_optional_maxthon:
47 Image|endswith: '\maxthon.exe'
48 filter_optional_edge_1:
49 - Image|contains: ':\Program Files (x86)\Microsoft\EdgeWebView\Application\'
50 - Image|endswith:
51 - ':\Program Files (x86)\Microsoft\Edge\Application\msedge.exe'
52 - ':\Program Files\Microsoft\Edge\Application\msedge.exe'
53 - '\WindowsApps\MicrosoftEdge.exe'
54 filter_optional_edge_2:
55 Image|contains:
56 - ':\Program Files (x86)\Microsoft\EdgeCore\'
57 - ':\Program Files\Microsoft\EdgeCore\'
58 Image|endswith:
59 - '\msedge.exe'
60 - '\msedgewebview2.exe'
61 filter_optional_opera:
62 Image|endswith: '\opera.exe'
63 filter_optional_safari:
64 Image|endswith: '\safari.exe'
65 filter_optional_seamonkey:
66 Image|endswith: '\seamonkey.exe'
67 filter_optional_vivaldi:
68 Image|endswith: '\vivaldi.exe'
69 filter_optional_whale:
70 Image|endswith: '\whale.exe'
71 filter_optional_googleupdate:
72 Image|endswith: '\GoogleUpdate.exe'
73 filter_optional_outlook.exe:
74 Image|endswith: '\outlook.exe'
75 filter_main_null:
76 Image: null
77 filter_main_empty:
78 Image: ''
79 condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
80falsepositives:
81 - 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.
82level: medium
References
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