Potential Rundll32 Execution With DLL Stored In ADS

Detects execution of rundll32 where the DLL being called is stored in an Alternate Data Stream (ADS).

Sigma rule (View on GitHub)

 1title: Potential Rundll32 Execution With DLL Stored In ADS
 2id: 9248c7e1-2bf3-4661-a22c-600a8040b446
 3status: test
 4description: Detects execution of rundll32 where the DLL being called is stored in an Alternate Data Stream (ADS).
 5references:
 6    - https://lolbas-project.github.io/lolbas/Binaries/Rundll32
 7author: Harjot Singh, '@cyb3rjy0t'
 8date: 2023-01-21
 9modified: 2023-02-08
10tags:
11    - attack.defense-evasion
12    - attack.t1564.004
13logsource:
14    category: process_creation
15    product: windows
16detection:
17    selection_img:
18        - Image|endswith: '\rundll32.exe'
19        - OriginalFileName: 'RUNDLL32.EXE'
20    selection_cli:
21        # Example:
22        #   rundll32 "C:\ads\file.txt:ADSDLL.dll",DllMain
23        # Note: This doesn't cover the use case where a full path for the DLL isn't used. As it requires a more expensive regex
24        CommandLine|re: '[Rr][Uu][Nn][Dd][Ll][Ll]32(\.[Ee][Xx][Ee])? \S+?\w:\S+?:'
25    condition: all of selection_*
26falsepositives:
27    - Unknown
28level: high

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