Use of Pcalua For Execution

Detects execition of commands and binaries from the context of The program compatibility assistant (Pcalua.exe). This can be used as a LOLBIN in order to bypass application whitelisting.

Sigma rule (View on GitHub)

 1title: Use of Pcalua For Execution
 2id: 0955e4e1-c281-4fb9-9ee1-5ee7b4b754d2
 3related:
 4    - id: fa47597e-90e9-41cd-ab72-c3b74cfb0d02
 5      type: obsoletes
 6status: test
 7description: Detects execition of commands and binaries from the context of The program compatibility assistant (Pcalua.exe). This can be used as a LOLBIN in order to bypass application whitelisting.
 8references:
 9    - https://lolbas-project.github.io/lolbas/Binaries/Pcalua/
10    - https://pentestlab.blog/2020/07/06/indirect-command-execution/
11author: Nasreddine Bencherchali (Nextron Systems), E.M. Anhaus (originally from Atomic Blue Detections, Endgame), oscd.community
12date: 2022/06/14
13modified: 2023/01/04
14tags:
15    - attack.execution
16    - attack.t1059
17logsource:
18    category: process_creation
19    product: windows
20detection:
21    selection:
22        Image|endswith: '\pcalua.exe'
23        CommandLine|contains: ' -a' # No space after the flag because it accepts anything as long as there a "-a"
24    condition: selection
25falsepositives:
26    - Legitimate use by a via a batch script or by an administrator.
27level: medium

References

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