Suspicious Child Process Of BgInfo.EXE

calendar Aug 12, 2024 · attack.execution attack.t1059.005 attack.defense-evasion attack.t1218 attack.t1202  ·
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Detects suspicious child processes of "BgInfo.exe" which could be a sign of potential abuse of the binary to proxy execution via external VBScript

Sigma rule (View on GitHub)

 1title: Suspicious Child Process Of BgInfo.EXE
 2id: 811f459f-9231-45d4-959a-0266c6311987
 3related:
 4    - id: aaf46cdc-934e-4284-b329-34aa701e3771
 5      type: similar
 6status: test
 7description: Detects suspicious child processes of "BgInfo.exe" which could be a sign of potential abuse of the binary to proxy execution via external VBScript
 8references:
 9    - https://lolbas-project.github.io/lolbas/OtherMSBinaries/Bginfo/
10    - https://oddvar.moe/2017/05/18/bypassing-application-whitelisting-with-bginfo/
11author: Nasreddine Bencherchali (Nextron Systems)
12date: 2023-08-16
13tags:
14    - attack.execution
15    - attack.t1059.005
16    - attack.defense-evasion
17    - attack.t1218
18    - attack.t1202
19logsource:
20    category: process_creation
21    product: windows
22detection:
23    selection_parent:
24        ParentImage|endswith:
25            - '\bginfo.exe'
26            - '\bginfo64.exe'
27    selection_child:
28        - Image|endswith:
29              - '\calc.exe'
30              - '\cmd.exe'
31              - '\cscript.exe'
32              - '\mshta.exe'
33              - '\notepad.exe'
34              - '\powershell.exe'
35              - '\pwsh.exe'
36              - '\wscript.exe'
37        - Image|contains:
38              - '\AppData\Local\'
39              - '\AppData\Roaming\'
40              - ':\Users\Public\'
41              - ':\Temp\'
42              - ':\Windows\Temp\'
43              - ':\PerfLogs\'
44    condition: all of selection_*
45falsepositives:
46    - Unknown
47level: high

References

  • Bginfo on LOLBAS

    Bginfo.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

  • Bypassing Application Whitelisting with BGInfo

    TL;DR BGinfo.exe older than version 4.22 can be used to bypass application whitelisting using vbscript inside a bgi file. This can run directly from a webdav server. UPDATE: 22.05.2017 AppLocker is…


    Read More

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