CVE-2022-49842: Linux Kernel Use-After-Free Vulnerability in snd_soc_exit()

Overview

The CVE-2022-49842 vulnerability is a critical use-after-free flaw found in the Linux kernel, specifically within the snd_soc_exit() function of the Advanced Linux Sound Architecture (ALSA) System on a Chip (SoC). Given the widespread use of Linux across various devices and systems, this vulnerability has potential wide-reaching implications. An attacker exploiting this flaw could compromise system integrity or leak sensitive data, thereby posing a significant threat to any system running a vulnerable version of the Linux kernel.

Vulnerability Summary

CVE ID: CVE-2022-49842
Severity: High (7.8)
Attack Vector: Local
Privileges Required: Low
User Interaction: None
Impact: System compromise or data leakage

Affected Products

Product | Affected Versions

Linux Kernel | Versions prior to the release of the vendor patch

How the Exploit Works

This use-after-free vulnerability is triggered by a failure within the snd_soc_init() function. Specifically, it fails to correctly handle errors when snd_soc_util_init() fails, leading to the unregistration of the soc_dummy_dev object twice. This results in a use-after-free condition, causing undefined behavior that could be exploited to execute arbitrary code or leak sensitive information.

Conceptual Example Code

While actual exploit code would be complex and highly dependent on the specific system configuration, a conceptual example might involve a local script or program that deliberately triggers the snd_soc_util_init() failure, then exploits the resulting use-after-free condition. It could look something like this:

#include <stdio.h>
#include <stdlib.h>
int main() {
// Trigger snd_soc_util_init() failure
trigger_snd_soc_util_init_failure();
// Exploit the use-after-free condition
exploit_snd_soc_exit_uaf();
return 0;
}

Impact and Mitigation

The impact of this vulnerability is severe, with a CVSS score of 7.8 indicating a high level of risk. Successful exploitation could lead to system compromise or data leakage.
As a mitigation measure, it is recommended to apply the latest vendor patches as soon as they become available. In the absence of a patch, it is advised to use a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to monitor and block potential exploitation attempts. Further, it is advisable to practice good cybersecurity hygiene such as segregating networks, maintaining least privilege, and monitoring system logs for any suspicious activity.