CVE-2005-1764 in Linux
Summary
by MITRE
Linux 2.6.11 on 64-bit x86 (x86_64) platforms does not use a guard page for the 47-bit address page to protect against an AMD K8 bug, which allows local users to cause a denial of service.
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Analysis
by VulDB Data Team • 07/06/2021
The vulnerability described in CVE-2005-1764 represents a critical design flaw in the Linux kernel's memory management implementation on 64-bit x86 platforms. This issue specifically affects Linux kernel versions up to 2.6.11 and manifests on AMD K8 architecture processors where the kernel fails to properly implement a guard page mechanism for the 47-bit address space page. The absence of this protective measure creates a potential pathway for local privilege escalation and system instability.
The technical flaw stems from the kernel's handling of virtual memory addressing on 64-bit systems where the processor supports a 47-bit virtual address space. In AMD K8 processors, there exists a known hardware bug that can cause system crashes or unpredictable behavior when certain memory access patterns are encountered. The Linux kernel should implement a guard page at the boundary of the 47-bit address space to prevent memory access violations that could trigger this hardware defect. However, the vulnerable kernel versions fail to establish this protective boundary, leaving the system exposed to conditions that could cause the processor to enter an undefined state.
This vulnerability operates at the intersection of kernel memory management and hardware-specific processor behaviors, creating a scenario where local users can exploit the missing guard page to induce system crashes. The operational impact extends beyond simple denial of service, as the AMD K8 bug can cause unpredictable system behavior including kernel panics, memory corruption, and potential data loss. The vulnerability is particularly concerning because it requires no special privileges beyond local user access, making it an attractive target for malicious actors seeking to disrupt system operations or gain unauthorized access to system resources.
The security implications of CVE-2005-1764 align with CWE-129 and CWE-119 categories, which address improper input validation and memory safety issues in kernel space operations. From an attack perspective, this vulnerability maps to ATT&CK technique T1068 which involves local privilege escalation through kernel exploits, and T1499 which covers network denial of service through system resource exhaustion. The vulnerability demonstrates how hardware-specific bugs can create software-level security gaps that require careful consideration of processor capabilities during kernel development. Organizations should implement immediate patching strategies to address this vulnerability, as the lack of a guard page creates an exploitable condition that can be leveraged for both disruptive and potentially malicious purposes.
Mitigation efforts should focus on upgrading to kernel versions that properly implement guard page mechanisms for 47-bit address space protection, with particular attention to the specific AMD K8 processor family. System administrators should also monitor for potential memory access patterns that could trigger the hardware bug, and consider implementing additional memory protection mechanisms. The vulnerability highlights the importance of comprehensive testing across different processor architectures during kernel development phases, ensuring that hardware-specific quirks are properly accounted for in memory management implementations. Regular security audits should verify that guard page mechanisms are properly configured and functioning as intended.