Shell Open Registry Keys Manipulation

Detects the shell open key manipulation (exefile and ms-settings) used for persistence and the pattern of UAC Bypass using fodhelper.exe, computerdefaults.exe, slui.exe via registry keys (e.g. UACMe 33 or 62)

Sigma rule (View on GitHub)

 1title: Shell Open Registry Keys Manipulation
 2id: 152f3630-77c1-4284-bcc0-4cc68ab2f6e7
 3status: test
 4description: Detects the shell open key manipulation (exefile and ms-settings) used for persistence and the pattern of UAC Bypass using fodhelper.exe, computerdefaults.exe, slui.exe via registry keys (e.g. UACMe 33 or 62)
 5references:
 6    - https://github.com/hfiref0x/UACME
 7    - https://winscripting.blog/2017/05/12/first-entry-welcome-and-uac-bypass/
 8    - https://github.com/RhinoSecurityLabs/Aggressor-Scripts/tree/master/UACBypass
 9    - https://tria.ge/211119-gs7rtshcfr/behavioral2 [Lokibot sample from Nov 2021]
10author: Christian Burkard (Nextron Systems)
11date: 2021-08-30
12modified: 2022-01-13
13tags:
14    - attack.defense-evasion
15    - attack.privilege-escalation
16    - attack.t1548.002
17    - attack.t1546.001
18logsource:
19    category: registry_event
20    product: windows
21detection:
22    selection1:
23        EventType: SetValue
24        TargetObject|endswith: 'Classes\ms-settings\shell\open\command\SymbolicLinkValue'
25        Details|contains: '\Software\Classes\{'
26    selection2:
27        TargetObject|endswith: 'Classes\ms-settings\shell\open\command\DelegateExecute'
28    selection3:
29        EventType: SetValue
30        TargetObject|endswith:
31            - 'Classes\ms-settings\shell\open\command\(Default)'
32            - 'Classes\exefile\shell\open\command\(Default)'
33    filter_sel3:
34        Details: '(Empty)'
35    condition: selection1 or selection2 or (selection3 and not filter_sel3)
36falsepositives:
37    - Unknown
38level: high

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