Potentially Suspicious Execution Of Regasm/Regsvcs With Uncommon Extension

calendar Aug 12, 2024 · attack.defense-evasion attack.t1218.009  ·
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Detects potentially suspicious execution of the Regasm/Regsvcs utilities with an uncommon extension.

Sigma rule (View on GitHub)

 1title: Potentially Suspicious Execution Of Regasm/Regsvcs With Uncommon Extension
 2id: e9f8f8cc-07cc-4e81-b724-f387db9175e4
 3related:
 4    - id: cc368ed0-2411-45dc-a222-510ace303cb2
 5      type: derived
 6status: test
 7description: Detects potentially suspicious execution of the Regasm/Regsvcs utilities with an uncommon extension.
 8references:
 9    - https://www.fortiguard.com/threat-signal-report/4718?s=09
10    - https://lolbas-project.github.io/lolbas/Binaries/Regasm/
11    - https://lolbas-project.github.io/lolbas/Binaries/Regsvcs/
12author: Nasreddine Bencherchali (Nextron Systems)
13date: 2023-02-13
14tags:
15    - attack.defense-evasion
16    - attack.t1218.009
17logsource:
18    category: process_creation
19    product: windows
20detection:
21    selection_img:
22        - Image|endswith:
23              - '\Regsvcs.exe'
24              - '\Regasm.exe'
25        - OriginalFileName:
26              - 'RegSvcs.exe'
27              - 'RegAsm.exe'
28    selection_extension:
29        CommandLine|contains:
30            # Note: Add more potentially uncommon extensions
31            - '.dat'
32            - '.gif'
33            - '.jpeg'
34            - '.jpg'
35            - '.png'
36            - '.txt'
37    condition: all of selection_*
38falsepositives:
39    - Unknown
40level: medium

References

  • Threat Signal Report | FortiGuard Labs

    FortiGuard Labs has found an active and widespread attack campaign that distributes a malware it dubs "RedInk", using the RegAsm.exe LOLBIN for exe...


    Read More

  • Regasm on LOLBAS

    Regasm.exe is a living-of-the-land file containing unexpected functionality that can be abused by attackers; this page lists all its use cases.


    Read More

  • Regsvcs on LOLBAS

    Regsvcs.exe is a living-of-the-land file containing unexpected functionality that can be abused by attackers; this page lists all its use cases.


    Read More

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