Dllhost.EXE Execution Anomaly

Detects a "dllhost" process spawning with no commandline arguments which is very rare to happen and could indicate process injection activity or malware mimicking similar system processes.

Sigma rule (View on GitHub)

 1title: Dllhost.EXE Execution Anomaly
 2id: e7888eb1-13b0-4616-bd99-4bc0c2b054b9
 3status: test
 4description: Detects a "dllhost" process spawning with no commandline arguments which is very rare to happen and could indicate process injection activity or malware mimicking similar system processes.
 5references:
 6    - https://redcanary.com/blog/child-processes/
 7    - https://nasbench.medium.com/what-is-the-dllhost-exe-process-actually-running-ef9fe4c19c08
 8    - https://www.ncsc.gov.uk/static-assets/documents/malware-analysis-reports/goofy-guineapig/NCSC-MAR-Goofy-Guineapig.pdf
 9author: Nasreddine Bencherchali (Nextron Systems)
10date: 2022/06/27
11modified: 2023/05/15
12tags:
13    - attack.defense_evasion
14    - attack.t1055
15logsource:
16    category: process_creation
17    product: windows
18detection:
19    selection:
20        Image|endswith: '\dllhost.exe'
21        CommandLine:
22            - 'dllhost.exe'
23            - 'dllhost'
24    filter_main_null:
25        CommandLine: null
26    condition: selection and not 1 of filter_main_*
27falsepositives:
28    - Unlikely
29level: high

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