CVE-2006-0741 in Linux
Summary
by MITRE
Linux kernel before 2.6.15.5, when running on Intel processors, allows local users to cause a denial of service ("endless recursive fault") via unknown attack vectors related to a "bad elf entry address."
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Analysis
by VulDB Data Team • 06/15/2019
The vulnerability identified as CVE-2006-0741 represents a critical flaw in the Linux kernel version 2.6.15.5 and earlier, specifically affecting systems running on Intel processors. This issue stems from improper handling of certain ELF (Executable and Linkable Format) entry addresses during kernel execution, creating a condition where the system can enter an infinite loop of recursive faults. The vulnerability operates at the kernel level and requires local user access, making it particularly concerning as it can be exploited by users with minimal privileges to disrupt system operations.
The technical root cause of this vulnerability lies in the kernel's memory management subsystem and its handling of executable file loading processes. When the kernel encounters an ELF file with a malformed or malicious entry address, the memory management unit fails to properly validate the address structure, leading to a cascade of fault handling mechanisms that repeatedly trigger the same error condition. This creates a recursive fault scenario where the kernel's page fault handler continuously calls itself without resolution, consuming system resources and ultimately rendering the system unresponsive. The issue is particularly insidious because it operates silently in the background, making detection difficult until the system becomes completely unresponsive.
From an operational impact perspective, this vulnerability presents a severe denial of service risk that can compromise entire system availability. The "endless recursive fault" condition essentially locks up the kernel's memory management subsystem, causing the system to become unresponsive to all user and system processes. Network services, user sessions, and critical system functions all cease to operate properly, resulting in complete system downtime. The vulnerability affects all Linux systems running kernel versions prior to 2.6.15.5 on Intel architectures, making it particularly widespread across enterprise and server environments. The impact extends beyond simple system crashes as the recursive fault condition can also cause data corruption and memory leaks that persist even after the initial attack vector is removed.
The vulnerability aligns with CWE-129, which addresses improper validation of input boundaries, and relates to the broader category of memory safety issues that affect kernel-level software. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique for "Endpoint Denial of Service" and represents a privilege escalation vector that can be leveraged for system compromise. Organizations should implement immediate patching strategies to upgrade to kernel version 2.6.15.5 or later, as this represents the official fix for the recursive fault handling issue. Additional mitigations include implementing kernel lockdown mechanisms, restricting local user privileges where possible, and monitoring for unusual memory fault patterns. System administrators should also consider implementing intrusion detection systems that can identify the characteristic recursive fault patterns associated with this vulnerability. The vulnerability demonstrates the critical importance of kernel security validation and proper input sanitization in preventing system-level exploits that can compromise entire computing environments.