Process Proxy Execution Via Squirrel.EXE

 1title: Process Proxy Execution Via Squirrel.EXE
 2id: 45239e6a-b035-4aaf-b339-8ad379fcb67e
 3related:
 4    - id: 1e75c1cc-c5d4-42aa-ac3d-91b0b68b3b4c
 5      type: similar
 6    - id: fa4b21c9-0057-4493-b289-2556416ae4d7
 7      type: obsoletes
 8status: experimental
 9description: |
10        Detects the usage of the "Squirrel.exe" binary to execute arbitrary processes. This binary is part of multiple Electron based software installations (Slack, Teams, Discord, etc.)
11references:
12    - https://lolbas-project.github.io/lolbas/OtherMSBinaries/Squirrel/
13    - http://www.hexacorn.com/blog/2019/03/30/sqirrel-packages-manager-as-a-lolbin-a-k-a-many-electron-apps-are-lolbins-by-default/
14    - http://www.hexacorn.com/blog/2018/08/16/squirrel-as-a-lolbin/
15author: Nasreddine Bencherchali (Nextron Systems), Karneades / Markus Neis, Jonhnathan Ribeiro, oscd.community
16date: 2022/06/09
17modified: 2023/11/09
18tags:
19    - attack.defense_evasion
20    - attack.execution
21    - attack.t1218
22logsource:
23    category: process_creation
24    product: windows
25detection:
26    selection_img:
27        Image|endswith:
28            - '\squirrel.exe'
29            - '\update.exe'
30    selection_exec:
31        CommandLine|contains:
32            - '--processStart'
33            - '--processStartAndWait'
34            - '--createShortcut'
35    filter_optional_discord:
36        CommandLine|contains|all:
37            - ':\Users\'
38            - '\AppData\Local\Discord\Update.exe'
39            - ' --processStart'
40            - 'Discord.exe'
41    filter_optional_github_desktop:
42        CommandLine|contains|all:
43            - ':\Users\'
44            - '\AppData\Local\GitHubDesktop\Update.exe'
45            - 'GitHubDesktop.exe'
46        CommandLine|contains:
47            - '--createShortcut'
48            - '--processStartAndWait'
49    filter_optional_teams:
50        CommandLine|contains|all:
51            - ':\Users\'
52            - '\AppData\Local\Microsoft\Teams\Update.exe'
53            - 'Teams.exe'
54        CommandLine|contains:
55            - '--processStart'
56            - '--createShortcut'
57    filter_optional_yammer:
58        CommandLine|contains|all:
59            - ':\Users\'
60            - '\AppData\Local\yammerdesktop\Update.exe'
61            - 'Yammer.exe'
62        CommandLine|contains:
63            - '--processStart'
64            - '--createShortcut'
65    condition: all of selection_* and not 1 of filter_optional_*
66falsepositives:
67    - Expected FP with some Electron based applications such as (1Clipboard, Beaker Browser, Caret, Discord, GitHub Desktop, etc.)
68level: medium