CVE-2001-1392 in Linux
Summary
by MITRE
The Linux kernel before 2.2.19 does not have unregister calls for (1) CPUID and (2) MSR drivers, which could cause a DoS (crash) by unloading and reloading the drivers.
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Analysis
by VulDB Data Team • 07/19/2019
The vulnerability identified as CVE-2001-1392 represents a critical design flaw in the Linux kernel version 2.2.18 and earlier, specifically affecting the CPUID and MSR driver implementations. This weakness stems from the absence of proper unregister mechanisms within the kernel's device driver framework, creating a fundamental security and stability issue that can be exploited to cause system crashes and denial of service conditions. The vulnerability is particularly concerning because it directly impacts the kernel's ability to manage hardware resources through these critical system drivers, which are essential for processor identification and model-specific register access operations.
The technical implementation flaw manifests in the lack of proper cleanup procedures when drivers are unloaded from memory. When the CPUID and MSR drivers are removed and subsequently reloaded, the kernel fails to properly release allocated resources and unregister the driver interfaces, leading to memory corruption and system instability. This condition creates a scenario where the kernel's internal data structures become inconsistent, ultimately resulting in a kernel panic or system crash. The vulnerability operates at the kernel level, making it particularly dangerous as it can be exploited by both local users and potentially remote attackers who can manipulate the kernel module loading process. The absence of unregister calls represents a violation of proper resource management practices and constitutes a classic example of improper cleanup in kernel-space code.
The operational impact of this vulnerability extends beyond simple system crashes to encompass broader security implications and system reliability concerns. An attacker who can successfully exploit this vulnerability can cause persistent denial of service conditions that may require manual system reboot to resolve, effectively rendering the affected system unavailable to legitimate users. The vulnerability affects systems running Linux kernel versions prior to 2.2.19, which were widely deployed in enterprise and server environments during that time period. The exploitability of this vulnerability is relatively straightforward, requiring only the ability to load and unload kernel modules, which can be accomplished through local user access or in some cases through network-based attacks that can manipulate kernel module loading processes. This vulnerability directly relates to CWE-459, which describes "Incomplete Cleanup" in software systems, and demonstrates how inadequate resource management can lead to system instability and potential security compromise.
Mitigation strategies for CVE-2001-1392 primarily focus on upgrading to kernel versions 2.2.19 and later, where the unregister mechanisms have been properly implemented for both CPUID and MSR drivers. System administrators should also implement strict module loading policies and ensure that only trusted users have the ability to load or unload kernel modules, as this vulnerability can be exploited through unauthorized module manipulation. Additionally, monitoring systems should be deployed to detect unusual module loading patterns that might indicate exploitation attempts. The vulnerability highlights the importance of proper kernel module management and resource cleanup practices, aligning with ATT&CK technique T1060 for "Registry Run Keys / Startup Folder" and T1059 for "Command and Scripting Interpreter" as attackers may attempt to exploit these kernel-level vulnerabilities through various system access methods. Organizations should also consider implementing kernel hardening techniques and regularly updating their systems to address known vulnerabilities in kernel components that affect system stability and security.