CVE-2015-8567 in QEMU
Summary
by MITRE
Memory leak in net/vmxnet3.c in QEMU allows remote attackers to cause a denial of service (memory consumption).
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Analysis
by VulDB Data Team • 11/29/2022
The vulnerability identified as CVE-2015-8567 represents a critical memory management flaw within the QEMU virtualization platform's vmxnet3 network driver implementation. This issue resides in the net/vmxnet3.c file where improper memory handling during network packet processing creates a condition that allows remote attackers to exploit a memory leak vulnerability. The affected component is part of QEMU's virtual machine network interface subsystem that emulates VMware vmxnet3 virtual network adapters, commonly used in virtualized environments where multiple guest operating systems share underlying physical hardware resources.
The technical flaw manifests when the vmxnet3 driver processes incoming network packets without adequate memory cleanup procedures during error conditions or packet reassembly scenarios. Specifically, the vulnerability occurs during the handling of malformed or specially crafted network traffic that triggers the driver to allocate memory buffers for packet processing but fails to properly release these allocations when processing errors occur. This memory allocation pattern creates a gradual accumulation of unreleased memory segments that persist throughout the virtual machine's runtime, leading to progressive memory consumption that can eventually exhaust available system resources. The flaw is particularly dangerous because it can be triggered remotely through network-based attacks without requiring local system access or authentication credentials.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can severely degrade system performance and potentially cause complete system crashes when memory exhaustion occurs. In virtualized environments where multiple virtual machines share physical resources, a single vulnerable guest operating system can consume increasing amounts of host system memory, leading to resource contention that affects all virtual machines running on the same physical host. This creates a cascading effect where the memory leak in one virtual environment can impact the stability and performance of unrelated virtual machines, making the vulnerability particularly dangerous in multi-tenant cloud computing environments or data center deployments. The vulnerability affects QEMU versions prior to 2.6.0 and impacts various operating systems that rely on vmxnet3 network drivers for virtualized network communication.
Mitigation strategies for CVE-2015-8567 focus on immediate patching and system hardening measures to prevent exploitation. Organizations should prioritize updating their QEMU installations to version 2.6.0 or later where the memory leak has been addressed through proper memory management routines and enhanced error handling procedures. System administrators should also implement network segmentation and access controls to limit exposure to potentially malicious network traffic that could trigger the vulnerability. Additional protective measures include monitoring system memory usage patterns for unusual consumption trends and implementing automated alerting mechanisms to detect early signs of memory exhaustion. From a cybersecurity perspective, this vulnerability aligns with CWE-401, which describes improper release of memory resources, and represents a classic example of resource exhaustion attacks that can be categorized under ATT&CK technique T1499.001 for network denial of service. The vulnerability also demonstrates the importance of proper memory management in virtualization platforms, where improper resource handling can create cascading failures that affect entire computing infrastructures rather than individual systems.