CVE-2023-33110: Race Condition Vulnerability in PCM Host Voice Audio Driver

Overview

This blog post aims to shed light on an intricate vulnerability, CVE-2023-33110, that has been identified in the PCM host voice audio driver. This vulnerability has widespread implications, as it affects any system that utilizes this driver for audio functionalities. The severity of this problem lies in its potential to cause memory corruption, which can lead to system compromise or data leakage. Given the ubiquity of this driver and the critical nature of the data it can access, it’s essential for IT professionals, system administrators, and developers to understand the vulnerability and apply necessary safeguards.

Vulnerability Summary

CVE ID: CVE-2023-33110
Severity: High – CVSS Score 7.8
Attack Vector: Local
Privileges Required: Low
User Interaction: None
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

PCM Host Voice Audio Driver | All versions before patch

How the Exploit Works

The vulnerability occurs due to a race condition between the event callback and the PCM close and reset session index. Specifically, the session index variable in the PCM host voice audio driver is initialized before the PCM is open. It is then accessed during the event callback from the ADSP. If the PCM close and reset session index operation overlaps with the event callback, it leads to a race condition. This race condition can result in memory corruption, which could potentially be exploited by an attacker to compromise the system or leak sensitive data.

Conceptual Example Code

The following is a conceptual example of how the vulnerability might be exploited. This pseudocode shows how an attacker might take advantage of the race condition:

// Attacker triggers event callback
triggerEventCallback();
// Attacker causes PCM to close and reset session index before event callback is done
forcePcmCloseReset();
// Memory corruption occurs due to race condition
exploitMemoryCorruption();

In the above pseudo code, `triggerEventCallback()` could be a function that causes an event callback in the PCM host voice audio driver. Meanwhile, `forcePcmCloseReset()` is a function that forces the PCM to close and reset the session index, creating a race condition. The function `exploitMemoryCorruption()` represents the attacker exploiting the resulting memory corruption.

Mitigation

The recommended mitigation strategy for this vulnerability is to apply the vendor patch. If the patch is not available or cannot be applied immediately, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation strategy. These tools can monitor the system for any unusual behavior and block or alert about any potential attacks. However, these are just temporary measures and cannot replace the need for the vendor patch. Regular updates and patches are crucial in maintaining robust cybersecurity.