CVE-2022-29829 - Understanding the Hard-coded Cryptographic Key Flaw in Mitsubishi Electric GX Works3, GT Designer3, and Related Software

Overview:
In 2022, a critical security vulnerability was discovered in several Mitsubishi Electric industrial software products. Tracked as CVE-2022-29829, this vulnerability centers around the use of a hard-coded cryptographic key. It affects popular software including GX Works3 (versions from 1.000A to 1.090U), GT Designer3 Version1 (GOT200) (versions from 1.122C to 1.290C), and Motion Control Setting related to GX Works3 (versions from 1.035M to 1.042U).

A hard-coded cryptographic key means that a secret encryption key is embedded directly into the software's code—leaving the door wide open for hackers. This vulnerability can allow remote, unauthenticated attackers to access or steal sensitive data, view or upload projects, and even execute malicious programs without needing any login credentials.

Why Is This a Big Deal?

Industrial control and automation software like Mitsubishi's is often used in factories, power plants, and other critical infrastructure. Many times, these systems are not updated frequently, and security was sometimes not a key focus when they were designed. This vulnerability means an attacker sitting anywhere on the network (or even the internet, if the system is exposed) could:

Extract intellectual property or sensitive process information.

- Illegally execute or modify operations on the controllers, potentially disrupting factories or other industrial processes.

How Does the Vulnerability Work?

Mitsubishi Electric's software uses cryptography to protect project files and communication with devices. Instead of asking the user for an encryption key, it uses a key hard-coded—literally "baked in"—to the source code.

Because the key does not change across installations, anyone who reverse-engineers the software can find out what the key is. They can then use that key to decrypt confidential data or craft malicious messages that look legitimate to the system.

Here’s a simple example in Python, simulating what a hard-coded key scenario looks like

# Simplified demo of hard-coded key usage
from Cryptodome.Cipher import AES

HARDCODED_KEY = b'0123456789abcdef'  # In reality, this would be discovered via reverse engineering
encrypted_data = b'\x8b\xd7...'

# Attackers who discover the key can decrypt the data:
cipher = AES.new(HARDCODED_KEY, AES.MODE_CBC, iv=b'InitializationVe')
decrypted = cipher.decrypt(encrypted_data)
print(decrypted)

In the real world, attackers decompile the Mitsubishi software to recover such a key, then use open-source cryptography tools to decrypt protected files or traffic.

Exploit Details

Step 1: Reverse engineer the software (using tools like IDA Pro or Ghidra) to extract the cryptographic key.

Step 2: Capture or obtain encrypted project files from the system.

Step 3: Use the discovered key with a decryption tool/script (like shown above) to view or alter contents.

Step 4: Re-encrypt tampered files or craft specially formed messages to push malicious programs or commands to devices.

Attack Scenarios

- Intellectual Property Theft: Attackers could steal proprietary logic or system configurations from project files.
- Sabotage: Programs can be illegally modified and uploaded, causing malfunction of industrial processes.
- Reconnaissance: Attackers learn how the system is configured, which helps in preparing further attacks.

Mitigation Steps

Mitsubishi Electric has released advisories and software updates to address the vulnerability. Users should:

References and Further Reading

- Mitsubishi Electric Official Advisory
- CISA ICS Advisory - ICSA-22-165-04
- MITRE CVE Record for CVE-2022-29829
- JPCERT/CC Alert

Conclusion

CVE-2022-29829 is not just a technical bug—it’s a wake-up call for industrial users and developers: cryptographic keys should never be hard-coded. This flaw is a textbook example of how "security by obscurity" fails. Rapid patching and defensive security best practices are crucial to stay ahead of attackers and keep the world's automation running safely.


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Timeline

Published on: 11/25/2022 00:15:00 UTC
Last modified on: 05/31/2023 09:15:00 UTC