CVE-2004-0075 in Linux
Summary
by MITRE
The Vicam USB driver in Linux before 2.4.25 does not use the copy_from_user function when copying data from userspace to kernel space, which crosses security boundaries and allows local users to cause a denial of service.
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Analysis
by VulDB Data Team • 06/01/2019
The vulnerability described in CVE-2004-0075 represents a critical security flaw in the Linux kernel's Vicam USB driver implementation prior to version 2.4.25. This issue stems from improper memory management practices within kernel space components that handle data transfer between user and kernel contexts. The vulnerability specifically affects the Vicam USB driver which is responsible for managing video capture devices connected via USB interfaces. When processing data from userspace applications, the driver fails to properly validate or copy data using the established kernel security mechanisms designed to prevent unauthorized access patterns. This fundamental flaw creates a dangerous condition where user-space processes can manipulate kernel memory in ways that were not intended or secured by the kernel's memory management subsystems.
The technical root cause of this vulnerability lies in the absence of proper data validation and copying mechanisms when transferring information from userspace to kernel space. The copy_from_user function serves as a critical kernel security primitive that ensures safe data transfer between these two distinct memory spaces while performing necessary validation checks. Without this function, the driver directly accesses user-provided data without proper boundary checking or validation, creating an opportunity for malicious or unintended data to corrupt kernel memory structures. This pattern directly violates the principle of least privilege and proper kernel security boundaries. The vulnerability manifests as a local denial of service condition because an attacker with access to the system can craft specific input data that causes the kernel to crash or become unresponsive when attempting to process the malformed data. This issue falls under the category of improper input validation and memory safety violations that are commonly classified under CWE-121 and CWE-125 in the Common Weakness Enumeration framework.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially compromise system stability and availability. Local users who can execute code on the system can leverage this flaw to crash kernel processes, leading to system hangs or reboots that disrupt normal operations. In environments where USB video capture devices are frequently used, this vulnerability could be exploited to repeatedly disrupt critical applications or services that depend on video input functionality. The vulnerability is particularly concerning because it affects the kernel level driver directly, meaning that successful exploitation can potentially lead to more severe consequences than typical user-space vulnerabilities. From an attack perspective, this vulnerability aligns with techniques described in the MITRE ATT&CK framework under the T1068 category for local privilege escalation and system resource hijacking, where attackers manipulate kernel components to achieve persistent access or service disruption.
The recommended mitigation strategy for this vulnerability involves upgrading to Linux kernel version 2.4.25 or later, where the proper copy_from_user function has been implemented in the Vicam USB driver. System administrators should also consider implementing additional security measures such as restricting user access to USB devices when possible, monitoring for unusual kernel memory access patterns, and maintaining current kernel versions with security patches. The vulnerability serves as an important reminder of the critical need for proper kernel memory management practices and the importance of using established kernel security APIs. Organizations should implement regular kernel patching procedures and conduct security audits of kernel modules to identify similar issues that may exist in other drivers or kernel components. Additionally, the vulnerability highlights the importance of proper code review processes for kernel-level code and the necessity of thorough testing of memory management functions before deployment in production environments.