CVE-2023-36570 - Breaking Down Microsoft Message Queuing Remote Code Execution Vulnerability

Microsoft’s Message Queuing (MSMQ) is a feature used by many Windows systems and enterprise apps to deliver messages between computers even when they’re offline. But in September 2023, Microsoft patched a scary Remote Code Execution (RCE) bug in this system—CVE-2023-36570. Today, we’ll unpack what that means for you, show an example exploit, and explain how to defend yourself.

What is CVE-2023-36570?

- CVE ID: CVE-2023-36570

Impacts: Windows systems running the MSMQ service

- Severity: *Critical* — 9.8/10 on CVSS

In short: If MSMQ is enabled, an attacker can send a carefully crafted network packet and gain control of the system—potentially with system privileges—without logging in.

Technical Details

MSMQ listens on TCP port 1801 by default. The vulnerability is in the way MSMQ handles packets. If a malicious packet is crafted and sent, it can corrupt memory (“heap buffer overflow”), which the attacker can use to run their own code.

Simple Python PoC Code Snippet

This example won’t give you a reverse shell, but it shows the vulnerable service can crash from a malformed packet — that’s the first step in confirming you’re exposed.

import socket

target_ip = 'TARGET_IP'
port = 1801

# This packet needs to be crafted to trigger the overflow – real exploits are private,
# but we'll send junk to crash the service for proof-of-concept
malicious_payload = b"A" * 1024  # Real exploit payload would be larger and more specific

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.connect((target_ip, port))
    s.sendall(malicious_payload)

print("Sent malicious packet. If MSMQ crashes, you're likely vulnerable!")

⚠️ WARNING: Never use this code against systems you do not own. This can crash or disrupt services.

How Attackers Exploit This

A skilled attacker could use a tool like Impacket to scan for MSMQ, then send proprietary packets that exploit this memory bug, and inject shellcode to open a command prompt, add admin users, install malware, or move deeper into your network.

Scan from outside: Use tools like Nmap

nmap -p 1801 TARGET_IP

If you see 1801/tcp open, and you didn’t mean to enable MSMQ, you’re potentially at risk.

Get the latest updates here:

Microsoft Security Response: CVE-2023-36570

Real References

- Microsoft Advisory
- Rapid7 Analysis

Conclusion

CVE-2023-36570 is not science fiction. It’s an easy-to-exploit, remotely triggerable bug with huge impact—especially for Windows servers running outdated MSMQ. You can defend yourself by patching, disabling unneeded services, and watching your network for unknown open ports.

Stay safe, keep your systems updated, and keep learning about the threats lurking behind seemingly old-school Windows features!

Timeline

Published on: 10/10/2023 18:15:13 UTC
Last modified on: 10/12/2023 17:51:16 UTC