CVE-2005-2617 in Linux
Summary
by MITRE
the syscall32_setup_pages function in syscall32.c for linux kernel 2.6.12 and later on the 64-bit x86 platform does not check the return value of the insert_vm_struct function which allows local users to trigger a memory leak via a 32-bit application with crafted elf headers.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 03/11/2015
The vulnerability described in CVE-2005-2617 represents a critical memory management flaw within the Linux kernel's compatibility layer for 64-bit x86 systems. This issue specifically affects kernel versions 2.6.12 and later, where the syscall32_setup_pages function fails to properly validate the return value from the insert_vm_struct function during the setup of virtual memory mappings for 32-bit applications running on 64-bit hardware. The flaw exists within the syscall32.c source file, which handles the translation of 32-bit system calls to their 64-bit equivalents, creating a potential avenue for memory corruption and resource exhaustion. The vulnerability is particularly concerning because it leverages the normal execution path of 32-bit applications through the compatibility layer, making it difficult to detect and exploit without proper system monitoring.
The technical implementation of this vulnerability stems from the absence of proper error handling within the kernel's virtual memory management subsystem. When a 32-bit application attempts to execute with crafted ELF headers, the syscall32_setup_pages function invokes insert_vm_struct to establish virtual memory regions for the process. However, the function does not verify whether insert_vm_struct successfully completed its operation, allowing potential memory allocation failures to go unnoticed. This oversight creates a scenario where memory structures that should be properly allocated and managed may be left in an inconsistent state, leading to memory leaks that accumulate over time. The flaw falls under the category of improper error handling as classified by CWE-754, where a function does not properly check for error conditions, and more specifically relates to CWE-457, which addresses the use of uninitialized memory. The vulnerability demonstrates a classic case of resource management failure where the kernel fails to properly account for virtual memory allocation results.
The operational impact of CVE-2005-2617 extends beyond simple memory consumption, potentially leading to system instability and denial of service conditions. Local attackers can exploit this vulnerability by crafting 32-bit ELF binaries with malformed headers that trigger the memory leak condition repeatedly. As the memory leak accumulates, system resources become increasingly constrained, potentially causing the kernel to fail in allocating new memory regions for legitimate processes. This condition can result in system crashes, application failures, or reduced system performance that may be difficult to diagnose due to the subtle nature of the memory corruption. The vulnerability's exploitation requires local access to the system, but given that it operates within the kernel's core memory management functions, successful exploitation can have far-reaching consequences for system integrity and availability. The attack pattern aligns with techniques described in the MITRE ATT&CK framework under the Tactic of Privilege Escalation and Resource Exhaustion, where adversaries leverage kernel-level flaws to consume system resources or create unstable conditions that can be leveraged for further compromise.
Mitigation strategies for this vulnerability require immediate kernel updates to versions that address the missing error checking in the syscall32.c file. System administrators should prioritize patching affected kernels to prevent exploitation, as the vulnerability represents a known security flaw that can be easily triggered by local users. Additionally, monitoring systems should be enhanced to detect unusual memory allocation patterns or repeated virtual memory mapping failures that might indicate exploitation attempts. The fix involves implementing proper error checking for the insert_vm_struct return value, ensuring that any allocation failures are properly handled and that memory resources are correctly managed. Organizations should also consider implementing process isolation measures for 32-bit applications running on 64-bit systems, particularly in environments where untrusted code execution is possible. The vulnerability highlights the importance of comprehensive error handling in kernel code and serves as a reminder of the critical nature of proper resource management in operating system internals, particularly within compatibility layers that bridge different architectural domains.