CVE-2004-0685 in Linux
Summary
by MITRE
Certain USB drivers in the Linux 2.4 kernel use the copy_to_user function on uninitialized structures, which could allow local users to obtain sensitive information by reading memory that was not cleared from previous usage.
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Analysis
by VulDB Data Team • 12/16/2024
The vulnerability described in CVE-2004-0685 represents a critical security flaw within the Linux 2.4 kernel's USB driver implementation that exposes sensitive data through improper memory handling practices. This issue specifically affects the copy_to_user function which is commonly used in kernel space to transfer data from kernel memory to user space. When USB drivers in the affected kernel versions utilize copy_to_user on structures that have not been properly initialized, they inadvertently expose uninitialized memory contents to local users who can then read this sensitive information through carefully crafted system calls or driver interactions.
The technical root cause of this vulnerability stems from a fundamental programming error where kernel developers failed to properly initialize memory structures before passing them to copy_to_user operations. This flaw falls under the category of information disclosure vulnerabilities and aligns with CWE-1284 which specifically addresses the improper initialization of memory structures in kernel space. The vulnerability exists because the kernel drivers do not clear or properly initialize the memory areas that are subsequently copied to user space, leaving behind data from previous operations or allocations that may contain sensitive information such as passwords, encryption keys, or other confidential system data. The impact is particularly severe because local users can exploit this weakness without requiring network access or special privileges, making it a significant concern for systems where local access is possible.
From an operational perspective, this vulnerability creates a substantial risk for systems running Linux 2.4 kernel versions, as any local user with access to the system can potentially extract sensitive information from kernel memory through USB driver interactions. The attack surface is broad since USB drivers are commonly used across various system components, including storage devices, network adapters, and peripheral hardware that may be connected to the system. This vulnerability directly impacts the confidentiality aspect of the system's security model and can lead to privilege escalation scenarios where attackers can gather sufficient information to mount more sophisticated attacks. The threat is particularly concerning in multi-user environments where unauthorized local access could provide attackers with access to sensitive data that was previously stored in kernel memory, potentially including cryptographic keys, session tokens, or system configuration details.
The mitigation strategies for this vulnerability primarily involve upgrading to patched kernel versions where the USB drivers properly initialize memory structures before using copy_to_user operations. System administrators should prioritize updating their Linux 2.4 kernel installations to versions that have addressed this specific memory initialization issue, as there are no effective workarounds that can be implemented at the user level. Additionally, implementing proper kernel memory management practices and conducting thorough code reviews for kernel modules can help prevent similar issues from occurring in future implementations. Organizations should also consider monitoring for any unauthorized local access to systems and implementing appropriate access controls to limit the potential impact of such vulnerabilities. The remediation process should include comprehensive testing to ensure that the kernel updates do not introduce compatibility issues with existing USB hardware or driver configurations, as the fix may require changes to driver initialization routines that could affect system stability.