CVE-2009-4067: 
Linux Kernel vulnerability analysis and mitigation

CVE-2009-4067 is a buffer overflow vulnerability discovered in the auerswald_probe function within the Auerswald Linux USB driver for Linux kernel versions before 2.6.27. The vulnerability affects the handling of USB string descriptors in the Auerswald PBX/System Telephone USB driver implementation (NVD, Red Hat).

The vulnerability exists in the auerswald_probe function where it incorrectly handles lengths of the USB string descriptors. The issue was present in the Linux kernel's Auerswald PBX/System Telephone USB driver implementation. The vulnerable code was completely removed from the kernel in version 2.6.27 rather than being patched (Red Hat Bugzilla).

A local attacker with physical access to the system could exploit this vulnerability by inserting a specially crafted USB device to gain root privileges on the affected system (Ubuntu Notice).

The primary mitigation was the removal of the affected driver code in Linux kernel version 2.6.27. For systems running older kernel versions, updates were provided by various distributions. For example, Ubuntu 8.04 users were advised to update to linux-image-2.6.24-29 packages, and a system reboot was required to apply the changes (Ubuntu Notice).