CVE-2013-4149 in QEMU
Summary
by MITRE
Buffer overflow in virtio_net_load function in net/virtio-net.c in QEMU 1.3.0 through 1.7.x before 1.7.2 might allow remote attackers to execute arbitrary code via a large MAC table.
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Analysis
by VulDB Data Team • 06/20/2021
The vulnerability identified as CVE-2013-4149 represents a critical buffer overflow flaw within the QEMU virtualization platform that affects versions 1.3.0 through 1.7.1. This issue resides in the virtio_net_load function located in the net/virtio-net.c source file, where improper input validation leads to memory corruption during MAC table processing. The vulnerability manifests when remote attackers send specially crafted network packets containing oversized MAC table entries, potentially enabling arbitrary code execution within the host system running the vulnerable QEMU instance. This represents a significant security risk as it allows attackers to exploit the virtualization layer and escalate privileges beyond the intended isolation boundaries of virtual machines.
The technical implementation of this vulnerability stems from inadequate bounds checking within the virtio_net_load function, which processes network configuration data for virtualized network interfaces. When the function encounters a large MAC table structure, it fails to properly validate the size of incoming data against predetermined buffer limits, creating a classic buffer overflow condition. The flaw operates at the network virtualization layer where guest operating systems communicate with virtualized network devices through virtio interfaces, making it particularly dangerous in cloud computing environments where multiple virtual machines share the same physical host. This vulnerability directly maps to CWE-121, which describes stack-based buffer overflow conditions, and can be categorized under ATT&CK technique T1059.007 for command and script injection through virtualization platforms. The attack vector requires network access to the virtual machine, typically through the guest operating system's network interface, making it exploitable in scenarios where guest-to-host communication is enabled.
The operational impact of CVE-2013-4149 extends beyond simple code execution, as it enables attackers to potentially compromise the entire host system and all other virtual machines running on the same physical hardware. In multi-tenant cloud environments, this vulnerability could allow a malicious guest to escape virtual machine isolation and access sensitive data from other customers' virtual machines, effectively breaking the fundamental security model of virtualization. The vulnerability's exploitation requires minimal privileges from the attacker's perspective, as it can be triggered through standard network traffic without requiring authentication or elevated access within the guest operating system. This makes it particularly dangerous in shared hosting environments, data centers, and cloud services where multiple users rely on virtualization for security isolation. The vulnerability also impacts containerized environments that utilize QEMU for virtualization, as the same code path is traversed regardless of the deployment model.
Mitigation strategies for CVE-2013-4149 primarily involve immediate patching of QEMU installations to versions 1.7.2 or later, where the buffer overflow has been corrected through proper bounds checking and input validation. Organizations should also implement network segmentation and access controls to limit the exposure of virtualized environments to untrusted networks, reducing the attack surface for potential exploitation. Additional defensive measures include monitoring network traffic for unusual MAC table entries and implementing virtualization-specific security controls such as SELinux or AppArmor policies to limit the privileges available to virtual machine processes. Network administrators should also consider disabling unnecessary virtio network features when they are not required for specific use cases, as this reduces the attack surface. The vulnerability highlights the importance of maintaining up-to-date virtualization software and implementing robust security monitoring practices to detect and respond to similar issues in virtualized environments. Organizations should also conduct regular vulnerability assessments of their virtualization infrastructure to identify and remediate similar flaws that may exist in other components of their virtualization stack, particularly given the complex attack surface presented by modern virtualization technologies.