Files Added To An Archive Using Rar.EXE

Detects usage of "rar" to add files to an archive for potential compression. An adversary may compress data (e.g. sensitive documents) that is collected prior to exfiltration in order to make it portable and minimize the amount of data sent over the network.

Sigma rule (View on GitHub)

 1title: Files Added To An Archive Using Rar.EXE
 2id: 6f3e2987-db24-4c78-a860-b4f4095a7095
 3status: test
 4description: Detects usage of "rar" to add files to an archive for potential compression. An adversary may compress data (e.g. sensitive documents) that is collected prior to exfiltration in order to make it portable and minimize the amount of data sent over the network.
 5references:
 6    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1560.001/T1560.001.md
 7    - https://eqllib.readthedocs.io/en/latest/analytics/1ec33c93-3d0b-4a28-8014-dbdaae5c60ae.html
 8author: Timur Zinniatullin, E.M. Anhaus, oscd.community
 9date: 2019-10-21
10modified: 2023-02-05
11tags:
12    - attack.collection
13    - attack.t1560.001
14logsource:
15    category: process_creation
16    product: windows
17detection:
18    selection:
19        Image|endswith: '\rar.exe'
20        CommandLine|contains: ' a '
21    condition: selection
22falsepositives:
23    - Highly likely if rar is a default archiver in the monitored environment.
24level: low

References

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