CVE-2023-47259: Critical XSS Vulnerability Discovered in Redmine before 4.2.11 and 5..x before 5..6

A serious Cross-Site Scripting (XSS) vulnerability has been identified in the widely used open-source project management software Redmine. It affects versions before 4.2.11 and 5..x before 5..6, putting countless projects and sensitive data at risk. In this in-depth post, we will discuss the origins of the vulnerability, its implications, and how to fix and prevent it.

Background

Redmine is a popular open-source project management and issue tracking software that organizations utilize to manage their projects effectively. Redmine's flexibility, extensibility, and widespread adoption make it a prime target for attackers seeking to exploit vulnerabilities.

The vulnerability (CVE-2023-47259) in question affects the Textile formatter, a component of Redmine responsible for converting plain text into formatted text. The formatter can inadvertently allow an attacker to execute malicious JavaScript code through XSS, giving them access to sensitive user and project data.

Vulnerability Details

The XSS vulnerability in Redmine is due to inadequate sanitization of user input by the Textile formatter. By inserting malicious JavaScript code within certain formatted text elements, such as links, an attacker can bypass Redmine's security measures and execute arbitrary JavaScript in the context of the user's browser session.

Below is a simple code snippet that demonstrates the vulnerability

"javascript:alert(1)//" *Click me* ":javascript:alert(1)//

When a user clicks on the "Click me" link, the JavaScript code (alert(1)) will be executed, triggering a simple alert. While this example is benign, it demonstrates the potential for more nefarious code execution in real-world exploitation scenarios.

Original references and disclosure

This vulnerability was initially disclosed by the security researcher who discovered it, and has since been acknowledged and addressed by the Redmine team. You can find the original disclosure here: Original Disclosure

The Redmine team has released the following security advisories in response to the vulnerability:
- Redmine Security Advisory for version 4.2.11
- Redmine Security Advisory for version 5..6

Exploit details

To exploit this vulnerability, an attacker may craft a malformed Textile-formatted message containing the malicious JavaScript code. Once the victim clicks a link or interacts with the message in some way, the code will execute within their browser context, potentially granting the attacker access to sensitive data or control over the user's session.

For example, by exploiting this vulnerability, an attacker may gain access to the following information:

Remediation steps

To mitigate this vulnerability, users are urged to update their Redmine installations to the latest patched versions (4.2.11 and 5..6) immediately. Updates can be obtained directly from the official Redmine website at the following links:
- Redmine 4.2.11 Download
- Redmine 5..6 Download

In addition to updating their software, users should remain vigilant and assess their projects and data for any signs of unauthorized access or manipulation resulting from this vulnerability.

Conclusion

This critical XSS vulnerability (CVE-2023-47259) in Redmine highlights the necessity for robust security practices and thorough code-review processes in both open-source and commercial software development. By keeping software up-to-date and adopting a proactive approach to security, individuals and organizations can reduce their risk of falling victim to potential exploits and data breaches.

Timeline

Published on: 11/05/2023 04:15:10 UTC
Last modified on: 11/14/2023 18:29:57 UTC