title: Remote Encrypting File System Abuse
id: 5f92fff9-82e2-48eb-8fc1-8b133556a551
status: test
description: Detects remote RPC calls to possibly abuse remote encryption service via MS-EFSR
references:
    - https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-36942
    - https://github.com/jsecurity101/MSRPC-to-ATTACK/blob/ddd4608fe8684fcf2fcf9b48c5f0b3c28097f8a3/documents/MS-EFSR.md
    - https://github.com/zeronetworks/rpcfirewall
    - https://zeronetworks.com/blog/stopping-lateral-movement-via-the-rpc-firewall/
author: Sagie Dulce, Dekel Paz
date: 2022-01-01
tags:
    - attack.lateral-movement
logsource:
    product: rpc_firewall
    category: application
    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'
detection:
    selection:
        EventLog: RPCFW
        EventID: 3
        InterfaceUuid:
            - df1941c5-fe89-4e79-bf10-463657acf44d
            - c681d488-d850-11d0-8c52-00c04fd90f7e
    condition: selection
falsepositives:
    - Legitimate usage of remote file encryption
level: high