CVE-2008-3272 in Linux
Summary
by MITRE
The snd_seq_oss_synth_make_info function in sound/core/seq/oss/seq_oss_synth.c in the sound subsystem in the Linux kernel before 2.6.27-rc2 does not verify that the device number is within the range defined by max_synthdev before returning certain data to the caller, which allows local users to obtain sensitive information.
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Analysis
by VulDB Data Team • 08/15/2019
The vulnerability described in CVE-2008-3272 resides within the Linux kernel's sound subsystem, specifically in the snd_seq_oss_synth_make_info function located in sound/core/seq/oss/seq_oss_synth.c. This flaw represents a classic buffer over-read or out-of-bounds access vulnerability that occurs when the kernel fails to properly validate input parameters before processing them. The issue affects Linux kernel versions prior to 2.6.27-rc2, indicating it was present in a significant portion of the kernel's history and could have been exploited by attackers with local access to affected systems. The vulnerability stems from inadequate bounds checking within the OSS (Open Sound System) compatibility layer that handles sequencer synthesizer device information retrieval.
The technical flaw manifests when the snd_seq_oss_synth_make_info function processes device number parameters without verifying that the device number falls within the valid range defined by the max_synthdev variable. This oversight allows local users to pass device numbers that exceed the allocated buffer boundaries, potentially causing the function to read beyond its intended memory allocation. When the function returns data to the caller, it may inadvertently expose kernel memory contents that contain sensitive information such as kernel stack contents, memory addresses, or other confidential data structures. The vulnerability specifically targets the sequencer synthesizer functionality within the OSS compatibility layer, which provides backward compatibility for older sound applications that rely on the legacy OSS interface.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with potential insights into kernel memory layout and internal state that could be leveraged for more sophisticated attacks. Local users who can execute code on the target system can exploit this vulnerability to gather sensitive kernel information that might aid in privilege escalation or other advanced exploitation techniques. The vulnerability's classification aligns with CWE-125: "Out-of-bounds Read" which is categorized under the broader weakness of improper input validation. From an ATT&CK perspective, this vulnerability maps to T1068: "Exploitation for Privilege Escalation" and T1005: "Data from Local System" as it enables information gathering that could lead to further system compromise. The attack vector requires local access, making it a low-privilege vulnerability that could be particularly dangerous in multi-user environments where less-privileged users might attempt to exploit it.
The remediation for CVE-2008-3272 involves implementing proper bounds checking within the snd_seq_oss_synth_make_info function to ensure that device numbers are validated against the max_synthdev limit before any data is returned to callers. This fix should be implemented as a defensive programming measure that validates all input parameters within kernel space functions, particularly those that handle device identifiers and memory access operations. System administrators should update to kernel versions 2.6.27-rc2 or later where this vulnerability has been patched, as the fix typically involves adding a simple range check that prevents out-of-bounds memory access. The vulnerability demonstrates the critical importance of input validation in kernel space code and highlights the need for rigorous security testing of system call interfaces, particularly those that provide compatibility layers for legacy applications. Organizations should also implement monitoring for unusual system behavior that might indicate exploitation attempts, as the information disclosure aspect of this vulnerability could be used as a reconnaissance step in more complex attack scenarios.