CVE-2010-5313 in Linux
Summary
by MITRE
Race condition in arch/x86/kvm/x86.c in the Linux kernel before 2.6.38 allows L2 guest OS users to cause a denial of service (L1 guest OS crash) via a crafted instruction that triggers an L2 emulation failure report, a similar issue to CVE-2014-7842.
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Analysis
by VulDB Data Team • 04/04/2022
The vulnerability described in CVE-2010-5313 represents a critical race condition within the Linux kernel's KVM (Kernel-based Virtual Machine) implementation, specifically affecting the x86 architecture. This flaw exists in the kernel version 2.6.38 and earlier, where the virtualization subsystem fails to properly handle certain emulation scenarios. The vulnerability stems from improper synchronization mechanisms during the handling of nested virtualization events, creating a window where malicious L2 guest operating systems can exploit timing discrepancies to disrupt the host system's operation. The race condition manifests when the kernel processes an L2 emulation failure report, which occurs during the execution of privileged instructions that require virtualization handling within a nested virtualization environment.
The technical flaw in this vulnerability resides in the arch/x86/kvm/x86.c file where the kernel fails to maintain proper atomicity when processing virtualization events between the guest and host systems. When an L2 guest executes a crafted instruction that triggers an emulation failure, the kernel's handling routine does not adequately synchronize access to shared data structures or state variables. This race condition allows an attacker within the L2 guest to manipulate the timing of operations in such a way that the L1 guest operating system experiences a crash or complete system failure. The vulnerability is particularly concerning because it operates at the hypervisor level, where the failure of the host system can lead to cascading effects across multiple virtualized environments. The flaw closely resembles CVE-2014-7842, indicating a pattern of similar race condition issues in the KVM subsystem's handling of nested virtualization scenarios, which suggests underlying architectural weaknesses in the virtualization handling code.
The operational impact of CVE-2010-5313 is severe and far-reaching within virtualized environments, particularly affecting cloud computing platforms, server virtualization systems, and any infrastructure relying on KVM-based virtualization. An attacker with access to an L2 guest can leverage this vulnerability to perform a denial of service attack against the L1 guest, effectively crashing the entire virtual machine or potentially causing the host system to become unstable. This type of attack can be particularly devastating in multi-tenant cloud environments where multiple customers' virtual machines share the same physical host, as a single compromised L2 guest could potentially affect other customers' workloads. The vulnerability also has implications for security research and penetration testing, as it demonstrates how virtualization boundaries can be circumvented to achieve privilege escalation or system compromise. Organizations using virtualized infrastructure must consider the broader implications of such vulnerabilities, as they can potentially be exploited to gain unauthorized access to sensitive data or disrupt critical business operations.
Mitigation strategies for CVE-2010-5313 primarily involve upgrading to kernel versions 2.6.38 or later, where the race condition has been addressed through improved synchronization mechanisms and proper handling of nested virtualization events. System administrators should implement comprehensive patch management procedures to ensure all virtualization hosts are updated promptly, particularly in environments where multiple tenants or untrusted guests may be present. Additional protective measures include implementing strict access controls and monitoring for unusual virtualization events, as well as employing hypervisor-level security features such as Intel VT-d or AMD-Vi to limit guest access to critical system resources. The vulnerability highlights the importance of proper virtualization security architecture and the need for thorough testing of virtualization components, particularly in complex nested virtualization scenarios. Organizations should also consider implementing network segmentation and isolation techniques to limit the potential impact of such vulnerabilities in their virtualized environments, as specified in industry standards such as the CWE-362 (Concurrent Execution Using Shared Resource with Unprotected Synchronization) classification. The ATT&CK framework would categorize this vulnerability under the technique of privilege escalation through hypervisor attacks, where adversaries leverage virtualization weaknesses to compromise the host system and potentially gain elevated privileges within the virtualized environment.