CVE-2015-8666 in QEMU
Summary
by MITRE
Heap-based buffer overflow in QEMU, when built with the Q35-chipset-based PC system emulator.
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Analysis
by VulDB Data Team • 11/28/2022
The heap-based buffer overflow vulnerability identified as CVE-2015-8666 affects QEMU virtual machine emulator when configured with the Q35-chipset-based PC system emulator. This vulnerability represents a critical security flaw that can potentially allow attackers to execute arbitrary code within the host system. The issue stems from improper input validation and memory management within the QEMU implementation, specifically when handling certain device configurations that utilize the Q35 chipset architecture. The vulnerability exists in the hypervisor layer where virtual machines interact with host system resources, creating a potential attack surface that could be exploited by malicious actors.
The technical flaw manifests as a heap-based buffer overflow during the processing of device configuration data within the QEMU emulator. When QEMU initializes with the Q35 chipset configuration, it allocates memory on the heap to store device state information and configuration parameters. However, the implementation fails to properly validate the size of incoming data before copying it into allocated heap buffers. This allows an attacker who can control the input to overflow the allocated buffer space and overwrite adjacent memory locations on the heap. The overflow can potentially overwrite function pointers, return addresses, or other critical control data structures, enabling arbitrary code execution with the privileges of the QEMU process. This vulnerability falls under CWE-121 heap-based buffer overflow classification and aligns with ATT&CK technique T1059 for command and scripting interpreter.
The operational impact of CVE-2015-8666 extends beyond simple privilege escalation as it can lead to complete system compromise when QEMU is running with elevated privileges. Virtualization environments utilizing QEMU with Q35 chipset configurations represent high-value targets for attackers seeking to break out of virtualized environments and gain access to underlying host systems. The vulnerability affects systems where QEMU is used for virtual machine hosting, cloud computing platforms, and development environments that rely on QEMU for testing and emulation purposes. Organizations running virtualized infrastructure may face significant security implications if this vulnerability is exploited, as attackers could potentially use it to escape virtual machine boundaries and compromise the entire host infrastructure. The impact is particularly severe in multi-tenant cloud environments where isolation between virtual machines is compromised.
Mitigation strategies for CVE-2015-8666 should prioritize immediate patching of affected QEMU versions to address the heap overflow vulnerability. System administrators should ensure that all QEMU installations are updated to versions that contain the appropriate memory validation fixes and heap management improvements. Additionally, organizations should consider implementing network segmentation and access controls to limit exposure of QEMU environments to untrusted networks. Monitoring for unusual network activity or process behavior that might indicate exploitation attempts should be implemented. The use of virtualization security solutions and hypervisor hardening measures can provide additional defense layers. For environments where immediate patching is not feasible, operational mitigations include restricting QEMU execution privileges, implementing strict input validation for device configurations, and regularly auditing virtual machine configurations to ensure compliance with security baselines. Organizations should also consider implementing runtime protection mechanisms and memory protection features such as stack canaries and address space layout randomization to reduce exploit success rates.