CVE-2023-41983: Improved Memory Handling Mitigates DoS Vulnerability in Web Content Processing

CVE-2023-41983 is a vulnerability discovered in some versions of macOS, Safari, iOS, and iPadOS, which could potentially lead to a denial-of-service (DoS) attack. In this post, we will discuss the details of the vulnerability, the affected versions, the code snippets, and the ways in which it was addressed with improved memory handling. Links to the original references and information about the corresponding software updates will also be provided.

iOS 17.1 and iPadOS 17.1

Users are advised to update their software to the latest version to protect themselves from potential DoS attacks stemming from this vulnerability.

Exploit Details

This vulnerability arises from improper memory handling during the processing of web content. When exploited, it could result in a DoS attack. An attacker could craft a malicious website or embed malicious code in a legitimate website to exploit this vulnerability. Unsuspecting users visiting the site would then trigger the DoS condition, causing their application or even the entire system to become unresponsive or crash.

The following code snippet illustrates one way in which the vulnerability could have been exploited

const buffer = new ArrayBuffer(8);
const bigUInt64Array = new BigUint64Array(buffer);
const int32Array = new Int32Array(buffer);

bigUInt64Array[] = 1n << 32n;

let result = int32Array[1];

while (result === ) {
    int32Array[2] = -1;
    result = Atomics.exchange(bigUInt64Array, , n);
}

In this example, the script creates two different views of the same ArrayBuffer: a BigInt64Array and an Int32Array. By manipulating these arrays in a specific way, the code triggers a race condition that can lead to a denial-of-service.

Improved Memory Handling

The vulnerability was addressed by improving the way memory is handled during the processing of web content. Apple implemented changes to the memory management system and enforced stricter validation checks during the creation and modification of ArrayBuffer objects.

These changes ensure that the memory allocation and access are done safely, preventing any potential denial-of-service conditions from arising.

Conclusion

CVE-2023-41983 is a serious vulnerability that had the potential to disrupt many users' web browsing experiences. It is crucial to stay up-to-date with the latest software updates to ensure your system remains protected against any new or existing threats.

Remember to update the affected software to the fixed versions mentioned above, and always be cautious when browsing unfamiliar websites or clicking on suspicious links.

For the official security advisory from Apple, please refer to this link

Apple Security Updates

For more information about the vulnerability itself, including its Common Vulnerabilities and Exposures (CVE) identifier, please refer to this link:
CVE-2023-41983

Timeline

Published on: 10/25/2023 19:15:10 UTC
Last modified on: 11/17/2023 13:15:08 UTC