CVE-2012-0810 in Linux
Summary
by MITRE
The int3 handler in the Linux kernel before 3.3 relies on a per-CPU debug stack, which allows local users to cause a denial of service (stack corruption and panic) via a crafted application that triggers certain lock contention.
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Analysis
by VulDB Data Team • 03/21/2021
The vulnerability described in CVE-2012-0810 represents a critical flaw in the Linux kernel's interrupt handling mechanism, specifically within the int3 handler that manages breakpoint exceptions. This issue affects kernel versions prior to 3.3 and stems from the kernel's reliance on per-CPU debug stacks for managing interrupt contexts. The vulnerability manifests when a local attacker crafts a specific application that deliberately triggers lock contention scenarios during interrupt processing, leading to stack corruption and ultimately system panic. The root cause lies in the improper management of stack memory regions during concurrent interrupt handling, where the per-CPU debug stack mechanism fails to adequately protect against race conditions and memory corruption during high-contention scenarios. This flaw operates at the kernel level and leverages the fundamental interrupt handling architecture that is critical for system stability and security.
The technical implementation of this vulnerability involves the exploitation of a race condition within the kernel's debug stack management subsystem. When multiple threads or processes attempt to access the same interrupt handler simultaneously, the per-CPU debug stack becomes corrupted due to insufficient synchronization mechanisms. The int3 handler, which is responsible for handling breakpoint exceptions typically used by debuggers and system monitoring tools, encounters memory corruption when lock contention occurs during stack operations. This corruption can manifest as stack pointer inconsistencies, memory overwrite conditions, or stack frame corruption that ultimately leads to kernel panic. The vulnerability specifically targets the kernel's interrupt descriptor table handling and debug stack allocation mechanisms, creating a scenario where legitimate system operations can be disrupted by malicious code execution.
The operational impact of CVE-2012-0810 extends beyond simple denial of service to potentially compromise system stability and availability. Local attackers can exploit this vulnerability to repeatedly trigger system panics, effectively rendering the affected system unusable until manual reboot occurs. The vulnerability is particularly concerning because it operates within the kernel's critical execution path and can be triggered by any application with sufficient privileges to execute code on the target system. This makes it a significant concern for systems where local privilege escalation is possible, as attackers could leverage this flaw to maintain persistent denial of service conditions. The vulnerability also has implications for system monitoring and debugging tools that rely on breakpoint exceptions, potentially causing legitimate debugging operations to fail or corrupt system state during critical operations.
Mitigation strategies for CVE-2012-0810 primarily focus on kernel version upgrades to 3.3 or later, where the vulnerability has been addressed through improved synchronization mechanisms and stack management. System administrators should prioritize patching affected systems and implementing proper access controls to limit local user privileges that could potentially exploit this vulnerability. Additional defensive measures include monitoring for unusual system behavior that might indicate lock contention scenarios, implementing proper resource management policies to reduce contention, and maintaining regular kernel updates as part of comprehensive security management practices. The vulnerability aligns with CWE-119 which addresses memory corruption issues, and represents a specific case of improper handling of concurrent access patterns in kernel space operations. From an attack perspective, this vulnerability falls under ATT&CK technique T1499 which covers endpoint detection evasion through system resource exhaustion and manipulation. Organizations should also consider implementing kernel hardening measures and monitoring for suspicious interrupt handling patterns that could indicate exploitation attempts.