CVE-2004-2607 in Linux
Summary
by MITRE
a numeric casting discrepancy in sdla_xfer in linux kernel 2.6.x up to 2.6.5 and 2.4 up to 2.4.29-rc1 allows local users to read portions of kernel memory via a large len argument which is received as an int but cast to a short which prevents a read loop from filling a buffer.
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Analysis
by VulDB Data Team • 06/30/2018
The vulnerability described in CVE-2004-2607 represents a critical numeric casting discrepancy within the linux kernel's sdla_xfer function that affects kernel versions 2.6.x through 2.6.5 and 2.4.x through 2.4.29-rc1. This issue stems from improper type handling during memory operations where a large length parameter is initially received as an integer type but subsequently cast to a shorter data type. The flaw exists in the software defined link access protocol implementation that manages communication between network devices and kernel space. When a local user submits a large len argument to this function, the casting operation truncates the value, creating a significant security risk that can be exploited to gain unauthorized access to kernel memory regions. The vulnerability specifically impacts the read loop functionality within the sdla_xfer function where the truncated length value prevents proper buffer filling operations, leaving portions of kernel memory accessible to unauthorized users.
The technical exploitation of this vulnerability relies on the fundamental principle of integer overflow and type conversion issues that are classified under CWE-194 in the CWE dictionary. The flaw demonstrates a classic case of improper type conversion where the kernel's memory management routines fail to properly validate or handle data type boundaries. When the integer value representing the length parameter exceeds the maximum value that can be represented by the short data type, the conversion results in a truncated value that does not accurately represent the intended memory access size. This creates a situation where the read loop executes fewer iterations than required, leaving kernel memory contents accessible through the improperly bounded buffer operations. The vulnerability specifically affects the software defined link access protocol implementation which handles network communication between user space applications and kernel network drivers, making it particularly dangerous for systems running vulnerable kernel versions.
The operational impact of CVE-2004-2607 extends beyond simple information disclosure to potentially enable more sophisticated attacks within the kernel context. Local users who exploit this vulnerability can read portions of kernel memory that may contain sensitive information such as cryptographic keys, network credentials, or other confidential data structures. This type of memory disclosure vulnerability can serve as a stepping stone for more advanced exploitation techniques, potentially allowing attackers to discover memory layout patterns and identify additional vulnerabilities within the kernel space. The attack vector requires local system access but does not need elevated privileges, making it particularly concerning for systems where local user access cannot be fully controlled. The vulnerability affects the kernel's ability to properly manage memory boundaries and can potentially lead to privilege escalation scenarios when combined with other exploitation techniques.
Mitigation strategies for CVE-2004-2607 focus on addressing the underlying type conversion issue within the kernel code and implementing proper bounds checking mechanisms. The most effective approach involves modifying the sdla_xfer function to maintain consistent data types throughout the memory operation processing, ensuring that length parameters are not truncated during type conversion. System administrators should prioritize updating to kernel versions that have patched this vulnerability, as the original affected versions (2.6.x through 2.6.5 and 2.4.x through 2.4.29-rc1) are no longer supported and contain multiple security vulnerabilities. Additionally, implementing proper input validation and boundary checking for all memory operations can help prevent similar issues from occurring in other kernel functions. The vulnerability aligns with ATT&CK technique T1068 which involves exploiting local privilege escalation opportunities, and addresses the broader category of kernel exploitation techniques that leverage memory corruption vulnerabilities. Organizations should also implement monitoring systems to detect potential exploitation attempts and maintain comprehensive security awareness programs to ensure proper kernel patch management across all systems.