Log4js Vulnerability: CVE-2022-21704 Impact & Fix

This article addresses a medium severity vulnerability (CVSS 5.5) found in the log4js-0.6.38.tgz library, identified as CVE-2022-21704. This vulnerability could potentially expose sensitive information due to world-readable file permissions. We'll delve into the specifics of this vulnerability, its potential impact, and, most importantly, how to remediate it. Understanding such vulnerabilities is crucial for maintaining the security and integrity of your applications. Let's explore how this specific issue in log4js can affect your projects and the steps you can take to mitigate the risk.

Understanding the Vulnerability

The vulnerability, CVE-2022-21704, affects the log4js-0.6.38.tgz library, a port of Log4js for Node.js. The core issue lies in the default file permissions assigned to log files created by the file, fileSync, and dateFile appenders. Specifically, these files are created with world-readable permissions on Unix-based systems. This means that any user on the system could potentially read the log files, which could be problematic if those logs contain sensitive data such as passwords, API keys, or other confidential information. The library's home page is located at https://registry.npmjs.org/log4js/-/log4js-0.6.38.tgz. The vulnerability resides within the /node_modules/log4js/package.json path, making it a direct dependency concern. This is a critical issue, as it directly impacts the confidentiality of data handled by applications using this version of log4js. The potential for unauthorized access to sensitive information is a significant risk that needs to be addressed promptly. Let's dive deeper into the specifics of how this vulnerability arises and what data might be at risk.

The Risk: World-Readable Log Files

The primary risk associated with CVE-2022-21704 stems from the fact that the default file permissions for log files are set to world-readable. This means that anyone with access to the system can potentially read these log files. If your application logs sensitive information, such as user credentials, API keys, or other confidential data, this vulnerability could lead to a significant security breach. Imagine a scenario where an attacker gains access to your system and is able to read the log files. They could potentially extract sensitive information and use it to compromise your application or even your entire system. This is why it's crucial to address this vulnerability as soon as possible. The impact of this vulnerability depends on the type of data being logged. If you're logging personally identifiable information (PII) or financial data, the risk is even higher. Ensuring that log files are properly protected is a fundamental security practice. Now, let's examine the technical details of the vulnerability and its potential exploitability.

Technical Details and Exploitability

Delving into the technical aspects, CVE-2022-21704 arises due to the lack of proper permission handling when creating log files. The log4js library, in the vulnerable version, does not enforce restrictive permissions by default. This omission results in the creation of log files with the default system permissions, which, in Unix-like environments, often include world-readability. While the vulnerability has a medium severity score of 5.5, its exploitability is a concern. The Exploit Maturity is marked as