CVE-2004-0415 in Linux
Summary
by MITRE
Linux kernel does not properly convert 64-bit file offset pointers to 32 bits, which allows local users to access portions of kernel memory.
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Analysis
by VulDB Data Team • 06/08/2024
The vulnerability described in CVE-2004-0415 represents a critical design flaw in the Linux kernel's handling of file offset conversions, specifically impacting the transition from 64-bit to 32-bit pointer representations. This issue arises from inadequate validation and conversion mechanisms within the kernel's file system subsystem, where the kernel fails to properly manage the conversion of large file offsets from 64-bit to 32-bit representations. The flaw exists in the kernel's implementation of system calls that deal with file operations, particularly those involving large file support and file positioning. When applications attempt to access files with offsets that exceed the range of 32-bit integers, the kernel's improper conversion process creates opportunities for unauthorized memory access patterns that can be exploited by local users.
The technical implementation of this vulnerability stems from the kernel's failure to properly validate or sanitize file offset values during the conversion process from 64-bit to 32-bit representations. This conversion typically occurs when the kernel processes system calls such as lseek, read, or write operations on files that may exceed 2GB in size. The improper handling manifests when the kernel truncates or masks the high-order bits of 64-bit file offset values without ensuring that the resulting 32-bit representation remains within valid memory boundaries. This creates a scenario where malicious local users can craft file operations that result in invalid memory addresses being accessed or manipulated, potentially leading to information disclosure or system instability. The vulnerability is classified under CWE-191, which deals with integer underflow and overflow conditions, and more specifically relates to improper handling of integer conversions and pointer arithmetic within kernel space operations.
The operational impact of CVE-2004-0415 extends beyond simple information disclosure, as it can enable local privilege escalation and system compromise when exploited effectively. An attacker with local access can leverage this vulnerability to read arbitrary kernel memory locations, potentially extracting sensitive information such as kernel pointers, credentials, or cryptographic keys that are stored in memory. The vulnerability is particularly dangerous because it allows for direct memory access without requiring network connectivity or external attack vectors, making it a significant concern for systems where local user access is possible. The exploitation typically involves crafting specific file operations that trigger the improper conversion path, potentially leading to information leakage that can be used to bypass security mechanisms or aid in further exploitation attempts. This vulnerability aligns with ATT&CK technique T1059.001 for command and script interpreter, where local users can leverage system call interfaces to manipulate kernel memory through crafted file operations.
Mitigation strategies for this vulnerability involve multiple layers of protection that address both the immediate kernel-level issue and broader system security considerations. The primary remediation requires updating to kernel versions that properly implement the conversion of 64-bit file offsets to 32-bit representations, ensuring that all high-order bits are correctly handled during the conversion process. System administrators should implement strict access controls and monitoring to detect unusual file operations that might indicate exploitation attempts, particularly those involving large file offsets or unusual seek patterns. The vulnerability highlights the importance of proper integer handling and memory management in kernel space, suggesting that additional defensive measures such as kernel address space layout randomization, stack canaries, and enhanced memory protection mechanisms should be considered. Regular security audits of kernel code, particularly around file system operations and integer conversion routines, can help identify similar vulnerabilities before they can be exploited. Organizations should also maintain up-to-date kernel security patches and implement comprehensive monitoring solutions that can detect anomalous file access patterns that may indicate attempts to exploit this or similar vulnerabilities. The fix typically involves ensuring that all file offset conversions properly validate the resulting 32-bit values against valid memory boundaries and implement proper overflow detection mechanisms to prevent the creation of invalid memory access patterns.