CVE-2022-42813: Critical Certificate Validation Issue in WKWebView Leads to Arbitrary Code Execution—How to Protect Yourself

Recently, a critical vulnerability, indexed as CVE-2022-42813, has been discovered in the widely-used WebKit, specifically in WKWebView. This vulnerability can lead to arbitrary code execution when processing malicious certificates. In this post, we will discuss the details of this vulnerability, including a detailed code snippet to demonstrate the issue, the affected software versions, and how to mitigate this risk. We will also provide links to the original reports and references to help you understand the issue and take action.

Background

WKWebView is an essential part of the WebKit framework for rendering web content in iOS, macOS, and other Apple platforms. It is used by many web apps and web browsers for optimal performance and compatibility.

The vulnerability in question is related to certificate validation. While handling a certificate, the affected WKWebView versions do not perform proper validation checks, which may allow attackers to craft malicious certificates and execute arbitrary code on target systems.

Here's a code snippet that demonstrates the vulnerability

import WebKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        let webView = WKWebView(frame: view.bounds)
        view.addSubview(webView)
        let url = URL(string: "https://malicious.example.com";)! // Replace with a malicious site using a crafted certificate
        webView.load(URLRequest(url: url))
    }
}

By navigating to a malicious website that serves a crafted certificate, the vulnerable WKWebView component might perform insufficient validation checks, ultimately leading to arbitrary code execution.

watchOS 9.1

You can find full details about this vulnerability on Apple's official security advisory: APPLE-SA-2023-06-30-1

Exploitation Details

To exploit this vulnerability, an attacker would need to craft a malicious certificate and a website that uses it. They would then need to induce the victim to visit the malicious website using a vulnerable version of WKWebView. Upon visiting the website, the victim's device could end up processing the malicious certificate without sufficient checks, which could result in arbitrary code execution on the device.

Mitigation and Best Practices

To protect yourself from this vulnerability, it is crucial to update all affected devices and software to the latest available versions:

Update watchOS to 9.1 or later

Developers should also update their apps to use the latest WebKit and WKWebView components and ensure that they follow best practices for certificate handling and validation.

Conclusion

CVE-2022-42813 is a critical vulnerability in WKWebView that can lead to arbitrary code execution when processing malicious certificates. It is crucial to update all affected devices and software to the latest versions. Vigilance, awareness, and timely updates are vital to keeping your systems secure and safeguarding them from potential attacks.

Timeline

Published on: 11/01/2022 20:15:00 UTC
Last modified on: 11/03/2022 12:54:00 UTC