CVE-2011-1477 in Linux
Summary
by MITRE
Multiple array index errors in sound/oss/opl3.c in the Linux kernel before 2.6.39 allow local users to cause a denial of service (heap memory corruption) or possibly gain privileges by leveraging write access to /dev/sequencer.
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Analysis
by VulDB Data Team • 12/05/2021
The vulnerability described in CVE-2011-1477 represents a critical heap memory corruption issue within the Linux kernel's Open Sound System OSS implementation, specifically in the opl3.c file that handles Yamaha OPL3 sound chip emulation. This flaw exists in kernel versions prior to 2.6.39 and affects systems utilizing the OSS sound subsystem. The vulnerability stems from multiple array index errors that occur during the processing of audio data through the /dev/sequencer device interface, which is commonly used by multimedia applications for sound synthesis and sequencing operations.
The technical nature of this vulnerability involves improper bounds checking within the sound subsystem's handling of sequence data packets. When a local user with write access to /dev/sequencer sends specially crafted data to the sound driver, the kernel fails to validate array indices properly, leading to heap memory corruption. This type of flaw falls under CWE-129 which describes improper validation of array indices, and specifically relates to CWE-787 which addresses out-of-bounds write conditions. The vulnerability exploits the fact that the opl3.c driver does not adequately validate the size and content of incoming sequence data, allowing an attacker to manipulate memory layout through controlled input.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enabling privilege escalation. Local attackers can leverage this flaw to corrupt heap memory structures, which may result in system crashes or more critically, allow for arbitrary code execution with kernel privileges. The attack vector requires only write access to the /dev/sequencer device, which is often accessible to regular users in many Linux distributions, making this vulnerability particularly dangerous. According to ATT&CK framework, this represents a privilege escalation technique through kernel vulnerabilities, specifically targeting the kernel's memory management subsystem.
The exploitation of CVE-2011-1477 demonstrates the importance of input validation in kernel space operations, as the flaw occurs during legitimate audio processing operations that applications perform through standard OSS interfaces. Systems running kernel versions before 2.6.39 are at risk, particularly those with multimedia applications that utilize the OSS sound subsystem. The vulnerability highlights the need for robust bounds checking in kernel drivers, as even seemingly benign operations like audio sequencing can become attack vectors when proper input validation is missing. Organizations should prioritize kernel updates to address this vulnerability and implement proper access controls to limit write access to critical device interfaces where possible. The remediation strategy involves upgrading to kernel version 2.6.39 or later, which includes proper bounds checking and memory validation mechanisms that prevent the array index errors from causing heap corruption.