CVE-2013-4127 in Linux
Summary
by MITRE
Use-after-free vulnerability in the vhost_net_set_backend function in drivers/vhost/net.c in the Linux kernel through 3.10.3 allows local users to cause a denial of service (OOPS and system crash) via vectors involving powering on a virtual machine.
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Analysis
by VulDB Data Team • 05/18/2021
The CVE-2013-4127 vulnerability represents a critical use-after-free flaw in the Linux kernel's virtualization subsystem that specifically targets the vhost_net driver component. This vulnerability exists within the drivers/vhost/net.c file and affects Linux kernel versions through 3.10.3, making it a long-standing issue that impacted a substantial portion of enterprise and server environments relying on virtualization technologies. The vulnerability is particularly concerning because it allows local users to trigger system instability through seemingly routine virtual machine management operations, specifically when powering on virtual machines that utilize vhost_net for network acceleration.
The technical root cause of this vulnerability lies in improper memory management within the vhost_net_set_backend function where the kernel fails to properly validate or release memory references before reassigning them during virtual machine state transitions. When a virtual machine is powered on using vhost_net backend functionality, the kernel allocates memory structures for network interface handling and subsequently attempts to reconfigure these structures. However, the code path does not adequately handle cases where freed memory pointers are still referenced or where concurrent access patterns create race conditions that result in memory corruption. This use-after-free condition occurs when the kernel attempts to access memory that has already been deallocated but not properly invalidated, leading to unpredictable behavior and system crashes.
The operational impact of CVE-2013-4127 extends beyond simple denial of service scenarios as it can result in complete system crashes and OOPS (Oops! kernel panic) conditions that require manual system reboot. Local attackers with access to virtual machine management capabilities can exploit this vulnerability to disrupt virtualization services, potentially affecting multiple virtual machines running on the same host system. In enterprise environments where virtualization is heavily utilized for server consolidation and cloud infrastructure, this vulnerability could lead to cascading failures affecting business-critical applications and services. The vulnerability's exploitation requires local access to the system but does not require elevated privileges, making it particularly dangerous in multi-tenant environments where guest operating systems might have limited user access but can still trigger host-level instability.
From a cybersecurity perspective, this vulnerability aligns with CWE-416 (Use After Free) which is classified as a fundamental memory safety issue that frequently leads to system compromise and denial of service conditions. The ATT&CK framework categorizes this vulnerability under T1499.004 (Endpoint Denial of Service) and potentially T1059.001 (Command and Scripting Interpreter) when exploited through legitimate administrative interfaces. Organizations should prioritize patching this vulnerability as it represents a well-known attack surface that could be leveraged by adversaries to establish persistent denial of service conditions against virtualized infrastructure. The vulnerability demonstrates the critical importance of proper memory management in kernel space code and highlights the need for comprehensive security testing of virtualization components. Mitigation strategies should include immediate kernel updates to versions beyond 3.10.3, implementing proper access controls to limit local user privileges, and monitoring for unusual virtual machine power-on activities that might indicate exploitation attempts.