Remote Encrypting File System Abuse

calendar Aug 12, 2024 · attack.lateral-movement  ·
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Detects remote RPC calls to possibly abuse remote encryption service via MS-EFSR

Sigma rule (View on GitHub)

 1title: Remote Encrypting File System Abuse
 2id: 5f92fff9-82e2-48eb-8fc1-8b133556a551
 3status: test
 4description: Detects remote RPC calls to possibly abuse remote encryption service via MS-EFSR
 5references:
 6    - https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-36942
 7    - https://github.com/jsecurity101/MSRPC-to-ATTACK/blob/ddd4608fe8684fcf2fcf9b48c5f0b3c28097f8a3/documents/MS-EFSR.md
 8    - https://github.com/zeronetworks/rpcfirewall
 9    - https://zeronetworks.com/blog/stopping-lateral-movement-via-the-rpc-firewall/
10author: Sagie Dulce, Dekel Paz
11date: 2022-01-01
12modified: 2022-01-01
13tags:
14    - attack.lateral-movement
15logsource:
16    product: rpc_firewall
17    category: application
18    definition: 'Requirements: install and apply the RPC Firewall to all processes with "audit:true action:block uuid:df1941c5-fe89-4e79-bf10-463657acf44d or c681d488-d850-11d0-8c52-00c04fd90f7e'
19detection:
20    selection:
21        EventLog: RPCFW
22        EventID: 3
23        InterfaceUuid:
24            - df1941c5-fe89-4e79-bf10-463657acf44d
25            - c681d488-d850-11d0-8c52-00c04fd90f7e
26    condition: selection
27falsepositives:
28    - Legitimate usage of remote file encryption
29level: high

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