In this post, we will delve into the details of a recently discovered security vulnerability, CVE-2023-34478, affecting Apache Shiro. We will discuss the cause of this vulnerability, how it can be exploited, and the mitigation steps that are available to address it.

What is Apache Shiro?
Apache Shiro is a powerful and easy-to-use security framework that helps developers to implement authentication, authorization, cryptography, and session management in their web applications. It is designed to be highly configurable and allows developers to quickly build secure applications.

The Vulnerability (CVE-2023-34478)

The vulnerability, which has been assigned the CVE identifier CVE-2023-34478, affects versions of Apache Shiro prior to 1.12. or 2..-alpha-3. It involves a path traversal attack that could allow an attacker to bypass the authentication mechanism when Shiro is used in conjunction with APIs or other web frameworks.

This happens because Shiro is not fully normalizing the incoming requests and enabling the attacker to craft malicious URLs that bypass Shiro's authentication process.

Exploit Details

By exploiting this vulnerability, an attacker could potentially bypass the authentication process of a web application that is using Apache Shiro for security. This could allow an attacker to access sensitive information or perform unauthorized actions.

For example, consider the following code snippet from a web application using Apache Shiro for authentication and authorization:

// Configure Shiro for authentication
IniSecurityManagerFactory factory = new IniSecurityManagerFactory("classpath:shiro.ini");
SecurityManager securityManager = factory.getInstance();
SecurityUtils.setSecurityManager(securityManager);

// Check if the user is authenticated
Subject currentUser = SecurityUtils.getSubject();
if (!currentUser.isAuthenticated()) {
    // Redirect to the login page
    response.sendRedirect("/login");
} else {
    // Allow the request to proceed
    chain.doFilter(request, response);
}

In this scenario, an attacker could craft a malicious URL like /authenticated/../login, which would be interpreted by the web application as a request for the /login page. Since the if condition checks only for the authentication status and not the requested resource, the attacker would gain unauthorized access to the /login page even without being authenticated.

Mitigation

To mitigate this vulnerability, users should update their Apache Shiro installation to version 1.12. or newer or 2..-alpha-3 or newer.

These versions of Apache Shiro have implemented a fix that properly normalizes incoming requests and prevents the path traversal attack, ensuring the safety of your web applications.

For more information about CVE-2023-34478 and additional details about the vulnerability, please refer to the official sources:

1. Apache Shiro Security Bulletin: https://shiro.apache.org/security_bulletin.html
2. CVE Details: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-34478
3. NVD - National Vulnerability Database: https://nvd.nist.gov/vuln/detail/CVE-2023-34478

Conclusion

In this post, we've covered the critical CVE-2023-34478 vulnerability affecting Apache Shiro. By updating to the latest version of Shiro and ensuring proper request normalization, developers can help protect their web applications from this path traversal attack and potential authentication bypass. Stay vigilant and keep your web applications secure!

Timeline

Published on: 07/24/2023 19:15:00 UTC
Last modified on: 08/01/2023 19:15:00 UTC