CVE-2010-4527 in Linux
Summary
by MITRE
The load_mixer_volumes function in sound/oss/soundcard.c in the OSS sound subsystem in the Linux kernel before 2.6.37 incorrectly expects that a certain name field ends with a \0 character, which allows local users to conduct buffer overflow attacks and gain privileges, or possibly obtain sensitive information from kernel memory, via a SOUND_MIXER_SETLEVELS ioctl call.
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Analysis
by VulDB Data Team • 10/11/2021
The vulnerability described in CVE-2010-4527 represents a critical buffer overflow flaw within the Open Sound System (OSS) subsystem of the Linux kernel. This issue resides in the load_mixer_volumes function located in sound/oss/soundcard.c, where the kernel fails to properly validate input data when processing mixer volume configurations. The flaw specifically manifests when the function assumes that a particular name field terminates with a null character, creating a dangerous assumption that can be exploited by malicious actors. The vulnerability occurs during the processing of SOUND_MIXER_SETLEVELS ioctl calls, which are used to configure audio mixer settings within the kernel's sound subsystem.
The technical exploitation of this vulnerability stems from improper bounds checking and string handling within the kernel's OSS implementation. When a local user submits a specially crafted SOUND_MIXER_SETLEVELS ioctl request, the load_mixer_volumes function attempts to parse the name field without adequate validation of its length or termination. This oversight creates a classic buffer overflow condition where malicious input can overwrite adjacent memory locations in kernel space. The CWE-121 category applies here as this represents a buffer copy without proper length checks, allowing attackers to overwrite stack data or kernel memory regions. The flaw is particularly dangerous because it operates within kernel space, meaning successful exploitation can result in privilege escalation to root level access.
The operational impact of CVE-2010-4527 extends beyond simple local privilege escalation, potentially enabling attackers to extract sensitive information from kernel memory. This dual threat makes the vulnerability particularly attractive to threat actors who may seek both system control and data exfiltration capabilities. The vulnerability affects all Linux kernel versions prior to 2.6.37, representing a substantial attack surface given the widespread adoption of older kernel versions in enterprise environments. The attack vector requires local access to the system, but the privilege escalation potential means that even limited user access can be leveraged to achieve full system compromise. This vulnerability aligns with ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation' and T1005 which addresses 'Data from Local System', demonstrating how a single flaw can enable multiple attack objectives.
Mitigation strategies for CVE-2010-4527 focus primarily on kernel version updates and system hardening measures. The most effective solution involves upgrading to Linux kernel version 2.6.37 or later, where the buffer overflow issue has been resolved through proper input validation and bounds checking. System administrators should also implement proper access controls to limit local user privileges and monitor for suspicious ioctl activity. Additional mitigations include disabling unnecessary OSS sound drivers when not required, implementing kernel module signing to prevent unauthorized code execution, and conducting regular security audits of kernel configurations. The vulnerability demonstrates the importance of rigorous input validation in kernel space code and serves as a reminder that even seemingly minor assumptions about data format can create significant security risks. Organizations maintaining systems with older kernel versions should prioritize patch management and consider implementing additional security monitoring to detect potential exploitation attempts.