Permission Misconfiguration Reconnaissance Via Findstr.EXE

 1title: Permission Misconfiguration Reconnaissance Via Findstr.EXE
 2id: 47e4bab7-c626-47dc-967b-255608c9a920
 3status: experimental
 4description: Detects usage of findstr with the "EVERYONE" or "BUILTIN" keywords. This is seen being used in combination with "icacls" to look for misconfigured files or folders permissions
 5references:
 6    - https://www.absolomb.com/2018-01-26-Windows-Privilege-Escalation-Guide/
 7author: Nasreddine Bencherchali (Nextron Systems)
 8date: 2022/08/12
 9modified: 2023/03/05
10tags:
11    - attack.credential_access
12    - attack.t1552.006
13logsource:
14    category: process_creation
15    product: windows
16detection:
17    selection_findstr_img:
18        - Image|endswith: '\findstr.exe'
19        - OriginalFileName: 'FINDSTR.EXE'
20    selection_findstr_cli:
21        CommandLine|contains:
22            - '"Everyone"'
23            - "'Everyone'"
24            - '"BUILTIN\\"'
25            - "'BUILTIN\\'"
26    selection_special:
27        CommandLine|contains|all:
28            # Example CLI would be: icacls "C:\Program Files\*" 2>nul | findstr "(M)" | findstr "Everyone"
29            # You could extend it for other groups and users
30            #   Example: icacls "C:\Program Files\*" 2>nul | findstr "(M)" | findstr "BUILTIN\Users"
31            - 'icacls '
32            - 'findstr '
33            - 'Everyone'
34    condition: all of selection_findstr_* or selection_special
35falsepositives:
36    - Unknown
37level: medium