CVE-2022-30286: A Pyscriptjs Remote Code Execution Vulnerability in PyScript Demonstrator

A recently discovered vulnerability, CVE-2022-30286, affects the PyScript Demonstrator (pyscriptjs), which is a part of the PyScript package. The vulnerability allows a remote attacker to read Python source code, potentially leading to sensitive information disclosure and unauthorized access. This blog post intends to delve deeper into the vulnerability, its exploit details, and the implications it has. Further, links to original references and relevant code snippets will be provided. The main goal is to create awareness about the impact of such vulnerabilities and the importance of securing your applications and systems.

Exploit Details

The vulnerability in PyScript Demonstrator stems from a remote code execution flaw that allows a remote attacker to read Python source code. This could be exploited by an attacker to potentially access sensitive information in the source code, such as secret keys, passwords, or other information that should not be available to unauthorized users.

To understand how this vulnerability can be exploited, let's take a look at a sample code snippet

// This is an example of Python code that uses PyScript
import sys
from Pyscript import PyScript
code = """
a = 3
b = 4
c = a + b
print(c)"""

In this code example, the PyScript Demonstrator runs the Python code specified in the code variable. The vulnerability lies in the fact that an attacker can manipulate the input to read the source code file's content instead of executing it.

To exploit this vulnerability, an attacker can send a crafted request to the vulnerable application. For instance, the following CURL-based command can be used to demonstrate the exploit from an attacker's perspective:

curl -X POST -H "Content-type: application/json" -d '{"code": "open(\'source_file.py\').read()"}' 'https://example.com/api/pyscript-demonstrator';

In the above command, source_file.py is the target file containing sensitive Python source code and https://example.com/api/pyscript-demonstrator is the URL of the vulnerable PyScript Demonstrator API endpoint.

Upon successful exploitation, the attacker would be able to view and obtain the contents of the targeted Python source code file, potentially exposing sensitive information.

Original References

The following sources provide detailed information about CVE-2022-30286, including the official references and advisories:

1. NIST National Vulnerability Database (NVD)
2. CVE Details
3. PyScript GitHub Repository

Recommendations & Mitigation Measures

To protect your applications and systems from vulnerabilities like CVE-2022-30286, consider the following steps:

Update the PyScript package to the latest version that has fixed the vulnerability.

2. Implement strict input validation and sanitization methods to prevent unauthorized access and ensure that only the intended code is executed.

Regularly check and monitor your application logs for any suspicious activities.

4. Conduct frequent security audits and vulnerability assessments to promptly identify and address newly emerging threats.

Conclusion

CVE-2022-30286 is a critical vulnerability in the PyScript Demonstrator (pyscriptjs) that allows remote attackers to read Python source code. By understanding the exploit details and taking appropriate measures, it's possible to secure your applications and systems from this and other vulnerabilities. Security awareness is key to preventing such vulnerabilities from being exploited, and this post aims to contribute to that goal by shedding light on this critical security issue.

Timeline

Published on: 05/09/2022 12:15:00 UTC
Last modified on: 05/16/2022 18:47:00 UTC