CVE-2023-45683 : Security Advisory and Response

This article provides an in-depth overview of CVE-2023-45683, a vulnerability related to cross-site scripting via missing binding syntax validation in ACS location in github.com/crewjam/saml.

Understanding CVE-2023-45683

CVE-2023-45683 is a security vulnerability found in the saml library for the Go language package on github.com/crewjam. The issue arises from the lack of proper validation of ACS Location URI, leading to a cross-site scripting (XSS) vulnerability that could be exploited by attackers.

What is CVE-2023-45683?

The CVE-2023-45683 vulnerability allows attackers to register malicious Service Providers at the IdP and inject JavaScript in the ACS endpoint definition. This can result in XSS attacks in the IdP context during SAML SSO Flow, enabling attackers to perform unauthorized actions as the victim.

The Impact of CVE-2023-45683

The impact of this vulnerability is classified as HIGH with a base severity score of 7.1. Due to the improper neutralization of input during web page generation, attackers can exploit this flaw to execute XSS attacks, potentially compromising user data and system integrity.

Technical Details of CVE-2023-45683

The vulnerability in github.com/crewjam/saml affects versions below 0.4.14 where the lack of validation in the ACS Location URI parsing allows for XSS exploitation. The issue has been addressed in version 0.4.14 of the library.

Vulnerability Description

The vulnerability arises from the failure to validate the ACS Location URI according to the SAML binding being parsed, enabling attackers to manipulate the ACS endpoint definition and execute XSS attacks.

Affected Systems and Versions

The vulnerability impacts versions of the crewjam saml library prior to version 0.4.14. Users using affected versions are at risk of XSS attacks and unauthorized actions by attackers.

Exploitation Mechanism

By exploiting the lack of ACS Location URI validation, attackers can inject malicious scripts in the ACS endpoint definition, leading to XSS attacks during SAML SSO Flow. This allows them to impersonate victims and perform unauthorized actions.

Mitigation and Prevention

To mitigate the risks associated with CVE-2023-45683, users are advised to take immediate steps and implement long-term security practices.

Immediate Steps to Take

Users are recommended to update the crewjam saml library to version 0.4.14 to eliminate the vulnerability. Additionally, external validation of URLs in SAML metadata can help prevent XSS attacks.

Long-Term Security Practices

In the long term, users should restrict the ability for end-users to upload arbitrary metadata and follow secure coding practices to prevent XSS vulnerabilities.

Patching and Updates

Regularly update software components and libraries to the latest versions to ensure protection against known vulnerabilities and security threats.