CVE-2024-53197: Linux Kernel Buffer Overflow Vulnerability

CVE-2024-53197 Overview

CVE-2024-53197 is an out-of-bounds memory access vulnerability in the Linux kernel's ALSA USB-audio subsystem affecting Extigy and Mbox audio devices. The vulnerability occurs when a malicious USB device provides a bNumConfigurations value that exceeds the initial value used in usb_get_configuration() for allocating dev->config. This can lead to out-of-bounds accesses during subsequent operations such as usb_destroy_configuration().

This vulnerability has been added to CISA's Known Exploited Vulnerabilities (KEV) catalog, indicating active exploitation in the wild and requiring immediate attention from security teams.

Critical Impact

Local attackers with physical access or the ability to connect malicious USB devices can achieve arbitrary code execution with kernel privileges, potentially leading to complete system compromise.

Affected Products

• Linux Kernel (multiple versions)
• Debian Linux 11.0
• Systems using Extigy and Mbox USB audio devices

Discovery Timeline

• 2024-12-27 - CVE-2024-53197 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2024-53197

Vulnerability Analysis

This vulnerability resides in the ALSA (Advanced Linux Sound Architecture) USB-audio driver, specifically affecting the handling of Extigy and Mbox audio device configurations. The core issue is improper validation of USB device descriptor values during device enumeration and configuration.

When a USB device is connected, the kernel reads the device descriptor including the bNumConfigurations field, which specifies how many configurations the device supports. The kernel uses this value to allocate memory for the dev->config array. However, a malicious device can subsequently report a different (larger) bNumConfigurations value, causing the kernel to access memory beyond the allocated buffer boundaries.

The vulnerability is classified as CWE-787 (Out-of-bounds Write), which can result in memory corruption, system crashes, or arbitrary code execution in the context of the kernel. Given the local attack vector requiring physical USB access or control over USB device behavior, this vulnerability poses significant risk in environments where untrusted USB devices may be connected.

Root Cause

The root cause is insufficient validation of the bNumConfigurations value provided by USB devices in the ALSA USB-audio subsystem. The code path for Extigy and Mbox devices trusts the device-reported configuration count without verifying it against the initially allocated array size. This allows a mismatch between the allocated memory and the accessed indices, resulting in out-of-bounds memory operations.

Attack Vector

The attack requires local access to connect a malicious USB device to the target system. The attacker crafts a USB device (or modifies an existing device's firmware) to report an inconsistent bNumConfigurations value:

1. During initial enumeration, the device reports a small bNumConfigurations value, causing limited memory allocation
2. Subsequently, the device reports a larger configuration count, causing the kernel to access indices beyond the allocated array
3. The out-of-bounds access occurs during device configuration or destruction, potentially during usb_destroy_configuration()

The vulnerability can be triggered by:

• Connecting a physically modified Extigy or Mbox device
• Using a USB device emulator or programmable USB hardware
• Exploiting compromised USB firmware on otherwise legitimate devices

The attack does not require user interaction beyond the initial USB connection and executes with kernel privileges, making it particularly dangerous for systems in shared or public environments.

Detection Methods for CVE-2024-53197

Indicators of Compromise

• Unexpected kernel crashes or panics when USB audio devices are connected or disconnected
• Unusual USB device connection events in system logs, particularly involving Extigy or Mbox device identifiers
• Memory corruption indicators such as kernel oops messages referencing ALSA or USB subsystems
• Anomalous usb_destroy_configuration or usb_get_configuration call traces in kernel logs

Detection Strategies

• Monitor kernel logs (dmesg, /var/log/kern.log) for USB-related crashes or ALSA subsystem errors
• Deploy USB device whitelisting to restrict connections to known, trusted audio devices
• Use kernel tracing tools (ftrace, eBPF) to monitor USB configuration handling functions
• Implement endpoint detection rules for unusual USB device enumeration patterns

Monitoring Recommendations

• Enable detailed USB event logging via usbmon for forensic analysis capabilities
• Configure SentinelOne agents to monitor for kernel panic events and USB device anomalies
• Implement real-time alerting on systems where USB audio devices are not expected to be connected
• Review USB device connection logs periodically for unauthorized or unknown device identifiers

How to Mitigate CVE-2024-53197

Immediate Actions Required

• Apply the latest kernel patches from your Linux distribution immediately, as this vulnerability is actively exploited
• Disable USB audio device support if not required: blacklist the snd-usb-audio kernel module
• Restrict physical access to USB ports on sensitive systems
• Implement USB device authorization policies to prevent untrusted devices from enumerating

Patch Information

The Linux kernel maintainers have released patches across multiple stable kernel branches. The fix validates the bNumConfigurations value to ensure it does not exceed the initially allocated array size. Organizations should update to patched kernel versions as soon as possible.

Patch commits are available in the Linux Kernel Git Repository with multiple backports for various kernel versions. Debian users should refer to the Debian LTS Security Announcements for distribution-specific updates.

Given the vulnerability's inclusion in the CISA Known Exploited Vulnerabilities Catalog, federal agencies and critical infrastructure operators have mandated remediation timelines.

Workarounds

• Blacklist the snd-usb-audio module by adding blacklist snd-usb-audio to /etc/modprobe.d/blacklist.conf and regenerating initramfs
• Disable USB ports at the BIOS/UEFI level on systems that do not require USB functionality
• Use USB port blockers or hardware locks to prevent unauthorized device connections
• Implement SELinux or AppArmor policies to restrict USB device access to authorized processes only

# Disable USB audio module to mitigate CVE-2024-53197
echo "blacklist snd-usb-audio" | sudo tee /etc/modprobe.d/blacklist-usb-audio.conf
sudo update-initramfs -u

# Verify module is not loaded
lsmod | grep snd_usb_audio

# Remove module if currently loaded
sudo modprobe -r snd-usb-audio