CVE-2023-4698 – Improper Input Validation Exploit in GitHub Repository usememos/memos Prior to .13.2 – How It Works, and What You Need to Know

A new vulnerability, CVE-2023-4698, has been discovered, affecting the popular memos application software hosted on GitHub with repository named usememos/memos. This issue exists in versions prior to .13.2, which allows potential attackers to exploit improper input validation, potentially leading to security breaches and unauthorized access. This blog post aims to provide an in-depth look into the impact, the code snippets associated with the exploit, and the references for the vulnerability, as well as suggested mitigations.

Vulnerability Overview

CVE-2023-4698 refers to a vulnerability identified in the usememos/memos GitHub repository due to improper input validation. As a result, an attacker can exploit this flaw, potentially leading to unwanted behaviors within the application. The affected component is responsible for processing user input, and it fails to adequately check and sanitize data before processing it further. It is essential to understand the implications of this vulnerability and take preventive measures to secure your systems.

Code Snippet – The Exploitable Code

The following is a simplified version of the code snippet that contains the vulnerability in the usememos/memos package:

import os
import sys

def vulnerable_function(user_input):
    try:
        os.system(user_input)
    except Exception as e:
        print("Error: ", e)

if __name__ == "__main__":
    user_input = sys.argv[1]
    vulnerable_function(user_input)

As we can see, this code takes user input from the command-line arguments (sys.argv[1]) and passes it to a function named "vulnerable_function". Inside this function, the input is used as an argument for the os.system command, which is a security risk because user input may contain malicious characters, especially when no validation is being performed.

Exploit Details

Attackers can exploit the improper input validation by providing maliciously-crafted input to the affected functionality. For instance, an attacker could potentially insert commands that may execute with the privileges of the current user. Below is an example of how the exploit may look like:

python memos.py "echo 'exploited'> exploit.txt;ls"

This command line inserts a command that creates a new file called "exploit.txt" and writes the word "exploited" into it to prove the execution of the arbitrary command.

Mitigation

The primary solution to address CVE-2023-4698 is to update the usememos/memos package to the latest version .13.2 or above. The new version implements proper input validation, thereby mitigating the vulnerability. You can update the package by visiting the following link:

- GitHub Repository: https://github.com/usememos/memos

Additionally, as a general security practice, restrict user input in your applications and sanitize them before passing them to potentially dangerous functions.

For a thorough understanding of CVE-2023-4698, refer to the following sources of information

- CVE Reference Link
- National Vulnerability Database (NVD) Details

Conclusion

CVE-2023-4698 represents a significant security risk for those using usememos/memos repository prior to version .13.2. As an application developer or user, it's essential to stay informed about such vulnerabilities and take appropriate action to protect your systems and data. By staying up-to-date with security patches and updates, you can greatly minimize the risk of falling victim to cyber attacks.

Timeline

Published on: 09/01/2023 01:15:00 UTC
Last modified on: 09/01/2023 13:07:00 UTC