CVE-2003-0700 in Linux
Summary
by MITRE
The C-Media PCI sound driver in Linux before 2.4.22 does not use the get_user function to access userspace in certain conditions, which crosses security boundaries and may facilitate the exploitation of vulnerabilities, a different vulnerability than CVE-2003-0699.
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Analysis
by VulDB Data Team • 06/29/2021
The vulnerability described in CVE-2003-0700 represents a critical security flaw in the Linux kernel's C-Media PCI sound driver implementation prior to version 2.4.22. This issue stems from improper handling of userspace memory access within kernel space, creating a dangerous security boundary crossing that could enable malicious actors to exploit the system. The vulnerability specifically affects the kernel's sound subsystem where the driver fails to properly validate and access userspace memory regions, potentially allowing privilege escalation and system compromise.
The technical root cause of this vulnerability lies in the driver's failure to utilize the kernel's established get_user function for accessing userspace data. This function serves as a critical security mechanism that ensures proper memory access validation and prevents unauthorized memory operations. When the driver bypasses this function, it creates an opportunity for attackers to manipulate kernel memory directly through crafted userspace inputs. The vulnerability operates at the kernel level and specifically targets the sound driver's interaction with userspace applications, making it particularly dangerous as it can be exploited without requiring elevated privileges initially.
From an operational impact perspective, this vulnerability presents significant risks to system security and stability. Attackers could potentially leverage this flaw to execute arbitrary code within kernel space, bypassing standard security controls and gaining full system control. The vulnerability's impact extends beyond simple privilege escalation as it could enable persistent backdoor access, data theft, or complete system compromise. The fact that this affects a widely used sound driver means that numerous systems could be vulnerable, particularly those running older kernel versions where the patch has not been applied.
The security implications align with CWE-125: Out-of-bounds Read and CWE-787: Out-of-bounds Write, as the improper memory access creates opportunities for unauthorized memory manipulation. This vulnerability also maps to ATT&CK technique T1068: Exploitation for Privilege Escalation, where attackers exploit kernel-level vulnerabilities to gain elevated privileges. The attack surface is particularly concerning as sound drivers are commonly used in desktop environments and servers, making the exploitation vector accessible across various deployment scenarios. Organizations should prioritize patching their kernel versions to address this vulnerability and implement monitoring for potential exploitation attempts.
Mitigation strategies should focus on immediate kernel updates to version 2.4.22 or later, where the proper get_user function implementation has been applied. System administrators should also consider implementing kernel lockdown mechanisms and monitoring for unusual kernel memory access patterns. Additionally, regular security audits should verify that all kernel modules properly implement userspace memory access controls. The vulnerability demonstrates the importance of proper kernel security coding practices and the critical need for thorough code review of kernel subsystems that interact with userspace components. Organizations should also maintain updated security information exchange channels to stay informed about similar vulnerabilities in other kernel subsystems.