CVE-2013-4536 in QEMU
Summary
by MITRE • 05/28/2021
An user able to alter the savevm data (either on the disk or over the wire during migration) could use this flaw to to corrupt QEMU process memory on the (destination) host, which could potentially result in arbitrary code execution on the host with the privileges of the QEMU process.
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Analysis
by VulDB Data Team • 06/20/2021
The vulnerability identified as CVE-2013-4536 represents a critical memory corruption flaw within the QEMU virtualization platform that specifically affects the savevm functionality during virtual machine migration operations. This vulnerability exists in the way QEMU handles incoming migration data, creating a potential attack vector where malicious actors could manipulate migration streams to corrupt memory on the destination host system. The flaw is particularly dangerous because it operates at the hypervisor level, where it can potentially escalate privileges to match those of the QEMU process itself, which typically runs with elevated system privileges.
The technical implementation of this vulnerability stems from insufficient validation of savevm data during migration processes. When QEMU receives migration data from a source host, it processes this information to reconstruct the virtual machine state on the destination host. However, the vulnerability occurs because the system fails to properly validate the integrity and structure of the incoming data before attempting to deserialize and apply it to the destination process memory. This lack of proper input sanitization creates a path for attackers to craft specially crafted migration data that can cause memory corruption through buffer overflows, use-after-free conditions, or other memory safety violations. The vulnerability is categorized under CWE-121 as a stack-based buffer overflow and aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as exploitation could enable arbitrary code execution.
The operational impact of CVE-2013-4536 extends beyond simple memory corruption, as it fundamentally compromises the security boundary between virtual machines and the host system. An attacker who gains the ability to modify migration data can potentially execute arbitrary code with the privileges of the QEMU process, which often runs with root or administrator privileges on the host system. This scenario creates a severe privilege escalation vulnerability that could allow attackers to gain complete control over the host machine, potentially leading to data breaches, system compromise, or use as a pivot point for further attacks within a network. The vulnerability is particularly concerning in cloud computing environments where multiple virtual machines from different users may be migrated between hosts, as it could enable cross-tenant attacks or facilitate lateral movement within cloud infrastructures.
Mitigation strategies for this vulnerability must address both the immediate security gap and broader architectural considerations within virtualization environments. The primary remediation involves applying the official QEMU patch that implements proper validation of savevm data during migration operations, ensuring that all incoming migration data is thoroughly checked before any memory operations are performed. Organizations should also implement network segmentation and access controls around migration endpoints to limit who can initiate or modify migration streams, reducing the attack surface for this specific vulnerability. Additional defensive measures include monitoring migration traffic for anomalies, implementing strict authentication and encryption for migration protocols, and conducting regular security assessments of virtualization environments. From an ATT&CK perspective, this vulnerability highlights the importance of defending against techniques like T1068 for local privilege escalation and T1566 for social engineering through migration protocols, requiring comprehensive security controls that address both the technical flaw and potential attack vectors.