CVE-2023-44467: Bypassing the CVE-2023-36258 Fix for Arbitrary Code Execution via PALChain in langchain_experimental ..14

In this detailed analysis, we will uncover a potential vulnerability (CVE-2023-44467) that allows an attacker to bypass the earlier CVE-2023-36258 fix and execute arbitrary code via the PALChain in the Python exec method of the langchain_experimental library (version ..14).

langchain_experimental is a powerful library for programming language-related experiments which has undergone numerous security patches. One of these fixes (CVE-2023-36258) was intended to address an arbitrary code execution vulnerability. However, it appears that this vulnerability might still be present in the latest version.

Exploit Details

By leveraging the PALChain object of langchain_experimental (which is responsible for parsing and managing logic chains), an attacker can successfully bypass the intended fix and obtain arbitrary code execution via the Python exec method.

Here's a simple example that demonstrates this exploit. Please be cautious and only attempt this in a controlled environment:

import langchain_experimental

payload = """
class ArbitraryCode:
    def __call__(self):
        import os
        os.system('echo "You have been exploited"')  # Arbitrary code executed here

def exploit(lang_chain):
    lang_chain.create_node(ArbitraryCode())

chain = langchain_experimental.PALChain()
chain.add_interceptor("exploit", exploit)
chain.exec()

This code snippet shows how an attacker can create a custom ArbitraryCode class, then use the exploit function to inject this class into the lang_chain object as a callable instance. When the chain is executed using the exec method, the arbitrary code within the ArbitraryCode class is executed.

Original References

The original security fix (CVE-2023-36258) attempted to patch a similar vulnerability and can be found in the following resources:
1. langchain_experimental GitHub Repository
2. CVE-2023-36258 Vulnerability Details

However, despite the proposed fix, it seems that the vulnerability still persists in the langchain_experimental library version ..14 and can be exploited as shown in the above code snippet.

Mitigation

As a temporary solution, users of langchain_experimental should refrain from using untrusted code in any langchain_experimental context to avoid potential arbitrary code execution.

For library developers, it is strongly recommended to revisit the design and implementation of the PALChain object and its exec method in order to provide stronger protection against arbitrary code execution in the future.

Conclusion

In conclusion, CVE-2023-44467 is a critical vulnerability that allows attackers to bypass the intended CVE-2023-36258 fix and execute arbitrary code via the PALChain object in the langchain_experimental library. We provided an example code snippet that demonstrates this exploit in action and highlighted the importance of addressing this vulnerability.

Affected users and developers should take the necessary precautions and work on addressing this vulnerability in order to prevent potential malicious exploitation.

Timeline

Published on: 10/09/2023 20:15:10 UTC
Last modified on: 10/12/2023 18:37:32 UTC