CVE-2013-4592 in Linux
Summary
by MITRE
Memory leak in the __kvm_set_memory_region function in virt/kvm/kvm_main.c in the Linux kernel before 3.9 allows local users to cause a denial of service (memory consumption) by leveraging certain device access to trigger movement of memory slots.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 06/02/2021
The vulnerability identified as CVE-2013-4592 represents a critical memory management flaw within the Linux kernel's KVM virtualization subsystem. This issue exists in the __kvm_set_memory_region function located in virt/kvm/kvm_main.c file and affects Linux kernel versions prior to 3.9. The vulnerability stems from improper handling of memory slot movements during device access operations, creating a condition where memory resources are not properly released back to the system. This memory leak occurs when virtual machines attempt to reconfigure their memory mappings through device access mechanisms, leading to gradual accumulation of unreleased memory fragments that eventually consume system resources.
The technical exploitation of this vulnerability requires local user access with the ability to perform device operations within a virtualized environment. Attackers can leverage specific device access patterns to trigger memory slot movement operations that bypass normal memory cleanup procedures. When the __kvm_set_memory_region function processes these operations, it fails to properly deallocate previously allocated memory regions, resulting in memory fragmentation and progressive resource exhaustion. This behavior aligns with CWE-401, which specifically addresses improper memory management and memory leaks in software systems. The flaw demonstrates a classic case of resource management failure where allocated memory blocks are not properly deallocated, creating a persistent drain on available system memory.
The operational impact of this vulnerability manifests as a gradual degradation of system performance followed by complete denial of service conditions. As the memory leak accumulates over time, the affected system experiences increasing memory pressure, leading to reduced system responsiveness, application failures, and ultimately system crashes. The vulnerability is particularly dangerous in virtualized environments where multiple virtual machines share the same physical host, as a single malicious guest operating system could potentially consume all available memory resources and affect other virtual machines running on the same host. This scenario creates a significant threat to cloud computing environments and server consolidation platforms where resource exhaustion could lead to cascading failures affecting entire infrastructure components.
Mitigation strategies for CVE-2013-4592 primarily focus on kernel version upgrades to 3.9 or later versions where the memory management issue has been addressed through proper memory deallocation procedures. System administrators should implement immediate patching protocols to ensure all virtualization hosts are updated with the latest kernel versions containing the fix. Additionally, monitoring systems should be deployed to track memory consumption patterns in virtualized environments, enabling early detection of potential memory leak occurrences. The fix implemented in kernel version 3.9 addresses the root cause by ensuring proper memory cleanup during memory slot movement operations, preventing the accumulation of unreleased memory blocks. Organizations should also consider implementing resource limits and memory quotas for virtual machines to contain the impact of potential memory leaks and prevent single guests from consuming excessive system resources, aligning with ATT&CK technique T1499 which addresses resource exhaustion attacks through proper access control and resource management policies.