CVE-2013-0217 in Xen
Summary
by MITRE
Memory leak in drivers/net/xen-netback/netback.c in the Xen netback functionality in the Linux kernel before 3.7.8 allows guest OS users to cause a denial of service (memory consumption) by triggering certain error conditions.
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Analysis
by VulDB Data Team • 05/04/2021
The vulnerability identified as CVE-2013-0217 represents a critical memory management flaw within the Linux kernel's Xen netback driver implementation. This issue specifically affects systems utilizing Xen virtualization technology where guest operating systems communicate with host systems through network backends. The vulnerability exists in the drivers/net/xen-netback/netback.c file and impacts Linux kernel versions prior to 3.7.8, creating a significant security concern for virtualized environments where resource exhaustion can be exploited by malicious actors.
The technical flaw manifests as a memory leak that occurs when specific error conditions are triggered within the netback functionality. When guest operating systems encounter certain network-related errors during communication with the Xen hypervisor, the kernel fails to properly release allocated memory resources. This memory leak accumulates over time and can eventually consume all available system memory, leading to system instability and potential denial of service conditions. The vulnerability is particularly concerning because it can be exploited by unprivileged guest users, making it accessible to attackers who may not have elevated privileges within the virtualized environment.
The operational impact of this vulnerability extends beyond simple resource exhaustion, as it can severely compromise the stability and performance of virtualized infrastructures. In production environments, this memory leak can cause cascading failures where multiple guest VMs consume increasing amounts of host memory, potentially leading to complete system crashes or service outages. The vulnerability affects systems running Linux kernels 3.7.7 and earlier, including various enterprise distributions and cloud platforms that rely on Xen virtualization technology. Organizations with extensive virtualized deployments are particularly at risk, as the cumulative effect of memory leaks across multiple guest instances can quickly overwhelm host system resources.
The root cause of this vulnerability aligns with CWE-401, which identifies improper handling of memory allocation and deallocation as a common weakness in software systems. This memory leak represents a failure in proper resource management where allocated kernel memory is not consistently freed during error handling scenarios. From an attack perspective, this vulnerability maps to several ATT&CK techniques including privilege escalation through resource exhaustion and denial of service attacks. The flaw demonstrates how virtualization-specific components can introduce unique security risks that differ from traditional operating system vulnerabilities, particularly in environments where guest and host systems share resources.
Mitigation strategies for CVE-2013-0217 primarily involve upgrading to Linux kernel versions 3.7.8 or later where the memory leak has been addressed through proper resource cleanup mechanisms. System administrators should prioritize patching affected systems, particularly in cloud environments where multiple virtual machines may be running on shared infrastructure. Additionally, implementing monitoring solutions that track memory consumption patterns can help detect potential exploitation attempts before they lead to system failures. Organizations should also consider implementing resource limits and quotas for guest operating systems to prevent individual VMs from consuming excessive memory resources. The fix implemented in kernel 3.7.8 specifically addresses the improper memory handling during error conditions, ensuring that all allocated resources are properly released even when error scenarios occur.