ProjeQtOr, the free and open-source project management software, has recently been flagged by security researchers after discovering a potential Cross-Site Scripting (XSS) vulnerability in its version 11..2. This vulnerability (tagged with CVE identifier CVE-2023-49034) allows a remote attacker to execute arbitrary code by injecting a specially crafted script into the application. This post will provide an in-depth analysis of the vulnerability, how it works, and recommendations to mitigate the risk associated with it.

Vulnerability Details

The vulnerability in question is a type of XSS called Stored or Persistent XSS, which occurs when an attacker is able to store malicious code (typically JavaScript) within the web application itself. According to the researchers, the vulnerability is located in two particular PHP files, namely ack.php and security.php. The checkValidHtmlText function in these files is found to be the primary source of the vulnerability.

Here is the code snippet in question from the checkValidHtmlText function

function checkValidHtmlText($text, $complexAllowed=true, $withAlert=true) {
  // ...
  if ($complexAllowed) {
    $localPattern = $patternComplex;
  } else {
    $localPattern = $patternSimple;
  }
  // Loop on script tags with the pattern defined before
  // ...
}

To exploit this vulnerability, an attacker needs to send a crafted script within an HTTP request, which will then bypass the validation checks implemented in the mentioned function.

Exploiting the Vulnerability

An attacker can exploit this vulnerability by creating a specially crafted script that would bypass the validation checks in the checkValidHtmlText function. The attacker may craft a script like the following to inject into the HTTP request:

<script>alert('XSS')</script>

If the attacker manages to inject and store this script in the web application successfully, it will later execute when a user accesses the affected webpage, possibly leading to the theft of sensitive information or session hijacking.

1. CVE-2023-49034 Official Advisory
2. ProjeQtOr GitHub Repository

Recommendations

To protect against this vulnerability, it is strongly advised that users of ProjeQtOr should update to the latest version available. Moreover, application developers are recommended to:

Ensure proper input validation and sanitization techniques are implemented in the application.

2. Sanitize user input by leveraging security libraries like HTML-Purifier or OWASP Java HTML Sanitizer.

Use a secure content security policy (CSP) to mitigate the risk of XSS.

4. Educate developers and users on secure coding practices, including security awareness against XSS vulnerabilities.

Conclusion

The discovery of cross-site scripting vulnerabilities like CVE-2023-49034 serves as a reminder of the importance of implementing proper security measures in web applications. By staying informed about the latest vulnerabilities in software, developers can more effectively protect their applications and users. Consequently, users of the software should always make sure their applications are up to date and be vigilant about any software they use, especially open-source applications.

Timeline

Published on: 02/20/2024 21:15:07 UTC
Last modified on: 02/20/2024 21:52:55 UTC