PUA - Fast Reverse Proxy (FRP) Execution

Status: test
Severity: high
Log source: category process_creation, product windows
Author: frack113, Florian Roth
Source: github.com/SigmaHQ/sigma

Detects the use of Fast Reverse Proxy. frp is a fast reverse proxy to help you expose a local server behind a NAT or firewall to the Internet.

Known false positives

Legitimate use

MITRE ATT&CK coverage

Tactic	Techniques
Command & Control	`T1090` Proxy

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation

Rule body

title: PUA - Fast Reverse Proxy (FRP) Execution
id: 32410e29-5f94-4568-b6a3-d91a8adad863
status: test
description: Detects the use of Fast Reverse Proxy. frp is a fast reverse proxy to help you expose a local server behind a NAT or firewall to the Internet.
references:
    - https://asec.ahnlab.com/en/38156/
    - https://github.com/fatedier/frp
author: frack113, Florian Roth
date: 2022-09-02
modified: 2024-11-23
tags:
    - attack.command-and-control
    - attack.t1090
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        Image|endswith:
            - '\frpc.exe'
            - '\frps.exe'
    selection_cli:
        CommandLine|contains: '\frpc.ini'
    selection_hashes:
        # v0.44.0
        Hashes|contains:
            - "MD5=7D9C233B8C9E3F0EA290D2B84593C842"
            - "SHA1=06DDC9280E1F1810677935A2477012960905942F"
            - "SHA256=57B0936B8D336D8E981C169466A15A5FD21A7D5A2C7DAF62D5E142EE860E387C"
    condition: 1 of selection_*
falsepositives:
    - Legitimate use
level: high

Stages and Predicates

Stage 0: `condition`

1 of selection_*

Stage 1: `selection_img`

selection_img:
    Image|endswith:
        - '\frpc.exe'
        - '\frps.exe'

Stage 2: `selection_cli`

selection_cli:
    CommandLine|contains: '\frpc.ini'

Stage 3: `selection_hashes`

selection_hashes:
    Hashes|contains:
        - "MD5=7D9C233B8C9E3F0EA290D2B84593C842"
        - "SHA1=06DDC9280E1F1810677935A2477012960905942F"
        - "SHA256=57B0936B8D336D8E981C169466A15A5FD21A7D5A2C7DAF62D5E142EE860E387C"

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`\frpc.ini`	`field:"CommandLine" kind:match value:"\frpc.ini"`
`Hashes`	match	`MD5=7D9C233B8C9E3F0EA290D2B84593C842` `SHA1=06DDC9280E1F1810677935A2477012960905942F` `SHA256=57B0936B8D336D8E981C169466A15A5FD21A7D5A2C7DAF62D5E142EE860E387C`	`field:"Hashes" kind:match`
`Image`	ends_with	`\frpc.exe` `\frps.exe`	`field:"Image" kind:ends_with`

PUA - Fast Reverse Proxy (FRP) Execution

Known false positives

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection_img

Stage 2: selection_cli

Stage 3: selection_hashes

Indicators

Stage 0: `condition`

Stage 1: `selection_img`

Stage 2: `selection_cli`

Stage 3: `selection_hashes`