CVE-2005-0529 in Linux
Summary
by MITRE
Linux kernel 2.6.10 and 2.6.11rc1-bk6 uses different size types for offset arguments to the proc_file_read and locks_read_proc functions, which leads to a heap-based buffer overflow when a signed comparison causes negative integers to be used in a positive context.
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Analysis
by VulDB Data Team • 07/01/2019
The vulnerability described in CVE-2005-0529 represents a critical heap-based buffer overflow in the Linux kernel versions 2.6.10 and 2.6.11rc1-bk6. This flaw stems from a fundamental type mismatch between the offset arguments used in two distinct kernel functions: proc_file_read and locks_read_proc. The inconsistency in data types creates a scenario where signed integer values can be improperly interpreted in unsigned contexts, leading to unexpected behavior during memory operations. The issue manifests specifically when negative integers, resulting from signed comparisons, are passed as positive offset values to memory allocation functions, ultimately causing memory corruption in the heap region.
The technical root cause of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory boundaries. The flaw operates through a classic integer overflow scenario where the signed comparison logic fails to account for the potential for negative values to be passed to functions expecting positive offsets. This type of vulnerability falls under the broader category of CWE-191, which encompasses integer underflow conditions where signed integer operations produce values that are outside the valid range of the data type. The kernel's handling of process file reading operations creates an ideal environment for exploitation, as the proc filesystem provides a mechanism for users to access kernel memory through special files, making these functions particularly susceptible to malicious input manipulation.
The operational impact of CVE-2005-0529 extends beyond simple memory corruption, as it provides potential for privilege escalation and system compromise. Attackers can leverage this vulnerability to execute arbitrary code with kernel-level privileges, effectively bypassing user-space protections and gaining complete control over affected systems. The vulnerability is particularly dangerous because it affects core kernel functionality related to process management and file system operations, making it exploitable in various attack scenarios including local privilege escalation and remote code execution in certain configurations. The heap-based nature of the overflow means that memory corruption can lead to unpredictable system behavior, crashes, or more sophisticated exploitation techniques such as return-oriented programming or stack pivoting. This vulnerability demonstrates the critical importance of proper type checking and bounds validation in kernel space operations, as even subtle inconsistencies in parameter handling can lead to severe security implications.
Mitigation strategies for CVE-2005-0529 require immediate patching of affected kernel versions to address the type mismatch in the proc_file_read and locks_read_proc functions. System administrators should prioritize upgrading to kernel versions 2.6.11 or later where this vulnerability has been resolved through proper type alignment and bounds checking implementations. The fix typically involves ensuring that offset parameters maintain consistent data types throughout the function call chain, preventing signed integers from being incorrectly interpreted as unsigned values. Additional defensive measures include implementing kernel address space layout randomization, disabling unnecessary proc filesystem access where possible, and monitoring for anomalous system behavior that might indicate exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and kernel exploitation, specifically targeting the T1068 privilege escalation tactic and T1059 command and scripting interpreter techniques. Organizations should also consider implementing process monitoring and anomaly detection systems to identify potential exploitation attempts, as the vulnerability can be leveraged in conjunction with other attack vectors to achieve persistent system compromise.