Publicly Accessible RDP Service — Sigma Rule

Rule metadata and linked tags

Author: Josh Brower @DefensiveDepth. Source status: test; severity: high. Source dates: 2020-08-22 / 2024-03-13.

{
  "product": "zeek",
  "service": "rdp"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 62cf1e1b85ad05c19e904f537ccd7c49c94269622d5059813be0e1d759e8d5bd

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Publicly Accessible RDP Service
id: 1fc0809e-06bf-4de3-ad52-25e5263b7623
status: test
description: |
    Detects connections from routable IPs to an RDP listener. Which is indicative of a publicly-accessible RDP service.
author: Josh Brower @DefensiveDepth
date: 2020-08-22
modified: 2024-03-13
tags:
    - attack.lateral-movement
    - attack.t1021.001
logsource:
    product: zeek
    service: rdp
detection:
    selection:
        id.orig_h|cidr:
            - '::1/128'  # IPv6 loopback
            - '10.0.0.0/8'
            - '127.0.0.0/8'
            - '172.16.0.0/12'
            - '192.168.0.0/16'
            - '169.254.0.0/16'
            - '2620:83:8000::/48'
            - 'fc00::/7'  # IPv6 private addresses
            - 'fe80::/10'  # IPv6 link-local addresses
    # approved_rdp:
      # dst_ip:
        # - x.x.x.x
    condition: not selection # and not approved_rdp
falsepositives:
    - Although it is recommended to NOT have RDP exposed to the internet, verify that this is a) allowed b) the server has not already been compromised via some brute force or remote exploit since it has been exposed to the internet. Work to secure the server if you are unable to remove it from being exposed to the internet.
level: high

Original YAML and metadata in JSON

False positives

• Although it is recommended to NOT have RDP exposed to the internet, verify that this is a) allowed b) the server has not already been compromised via some brute force or remote exploit since it has been exposed to the internet. Work to secure the server if you are unable to remove it from being exposed to the internet.

Source references

No reviewed association in this snapshot.