CVE-2023-32370: Understanding the Content Security Policy Logic Issue and its Impact on macOS Ventura 13.3

CVE-2023-32370 identifies a critical logic issue that was discovered in macOS Ventura 13.3 systems. This post is intended to provide an in-depth understanding of the vulnerability, its potential impact, and the solution provided by the developers. The logic issue has been addressed with improved validation, and this post will discuss the Content Security Policy (CSP) that helps block domains with wildcards. Details of the exploit, code snippets, and links to the original references will be provided throughout this content piece.

Understanding the CVE-2023-32370 Vulnerability

This vulnerability is a logic issue that arises when handling wildcard subdomains in the Content Security Policy (CSP). CSP provides a powerful defense mechanism to protect websites from cross-site scripting (XSS) attacks, clickjacking, and other malicious activity. It allows website owners to define strict policies that govern what resources can be fetched or executed.

The logic issue in macOS Ventura 13.3 is primarily caused by a failure in the CSP to efficiently block domains with wildcards. This misbehavior allows attackers to bypass the policy restrictions and inject malicious content onto the affected systems.

Here is a simple snippet that exemplifies how a faulty CSP with a wildcard might look like

Content-Security-Policy: default-src 'self'; img-src https://*.example.com;

In this example, the CSP is intended to block any resources from being fetched or executed, except those originating from the same domain ('self') and image resources from subdomains under example.com. However, the vulnerability in macOS Ventura 13.3 allows attackers to bypass these restrictions by exploiting the wildcard logic issue.

Exploit Details

The exploit takes advantage of macOS Ventura 13.3's logic issue related to wildcards in CSPs. An attacker can craft a malicious website that appears to comply with the CSP and hence bypass the policy's restrictions. Here's a simple outline of the exploitation process:

The attacker creates a malicious website containing malicious code to execute on the target system.

2. The attacker crafts a URL that appears to be a subdomain of a trusted domain (as defined by the CSP) and sends it to the victim.

The victim clicks the link, which causes their browser to load the malicious content.

4. The malicious content evades detection and restrictions enforced by the CSP and executes within the victim's browser context.

The attacker can now potentially gain access to sensitive data, perform unauthorized actions on behalf of the user, or cause other malicious activity.

Official References and Patch Information

The logic issue was reported and addressed as part of macOS Ventura 13.3. The developers have provided improved validation to fix the issue and protect users from vulnerabilities associated with wildcards in CSPs.

Refer to the following official resources for further information

- CVE details: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-32370
- macOS update release notes: https://support.apple.com/en-us/HT212938

Conclusion

In summary, this post provided an in-depth analysis of the CVE-2023-32370 vulnerability found in macOS Ventura 13.3. The logic issue, which involves improper handling of wildcards in Content Security Policy, has been addressed with improved validation. Users are advised to update their systems to the latest version to stay protected against potential exploitation. It is crucial to stay informed and apply necessary security patches to prevent cyber threats.

Timeline

Published on: 09/06/2023 02:15:00 UTC
Last modified on: 09/11/2023 18:15:00 UTC