CVE-2005-0756 in Linux
Summary
by MITRE
ptrace in Linux kernel 2.6.8.1 does not properly verify addresses on the amd64 platform, which allows local users to cause a denial of service (kernel crash).
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Analysis
by VulDB Data Team • 07/03/2019
The vulnerability identified as CVE-2005-0756 resides within the ptrace system call implementation of the Linux kernel version 2.6.8.1 specifically affecting the amd64 platform architecture. This flaw represents a critical security weakness that undermines the kernel's memory management integrity and exposes the system to potential denial of service attacks. The ptrace system call serves as a fundamental debugging mechanism that allows one process to observe and control the execution of another process, making it an essential component for system administration and security analysis tools. However, the improper address verification mechanism creates a pathway for malicious local users to exploit the kernel's memory handling routines.
The technical root cause of this vulnerability stems from insufficient validation of memory addresses when the ptrace system call processes requests on amd64 platforms. During normal operation, ptrace should validate all memory addresses to ensure they fall within acceptable ranges and do not point to kernel memory regions that could cause system instability. The flaw occurs when the kernel fails to properly verify address boundaries, allowing crafted malicious input to reference memory locations that should be protected or otherwise inaccessible. This verification failure creates a condition where a local user can manipulate the ptrace system call to pass invalid memory addresses, leading to kernel memory corruption and ultimately system crashes.
The operational impact of this vulnerability extends beyond simple denial of service as it represents a fundamental breach in kernel security architecture that could potentially be exploited to escalate privileges or access sensitive system information. Local users with minimal privileges can leverage this flaw to crash the kernel, rendering the system unstable and potentially causing data loss or service interruption. The vulnerability affects systems running Linux kernel 2.6.8.1 and potentially other versions within the same release branch, making it particularly concerning for enterprise environments that may have multiple systems running this vulnerable kernel version. The amd64 platform-specific nature means that 64-bit systems are particularly at risk, while 32-bit systems may not be affected due to different memory management implementations.
This vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and represents a classic example of improper input validation in kernel space operations. The flaw demonstrates the critical importance of memory boundary checking in privileged system calls and highlights the potential for seemingly benign debugging features to become security risks when not properly implemented. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation and denial of service tactics, as it allows local users to disrupt system operations and potentially create conditions for further exploitation. The vulnerability also reflects the broader category of kernel-level memory corruption flaws that have historically been exploited to gain unauthorized access to systems. Mitigation strategies should focus on updating to patched kernel versions, implementing proper address validation mechanisms, and monitoring for suspicious ptrace activity that could indicate exploitation attempts. System administrators should also consider implementing additional security controls such as process monitoring and kernel hardening measures to reduce the attack surface and prevent unauthorized access to privileged system calls.