CVE-2011-2212 in qemu
Summary
by MITRE
Buffer overflow in the virtio subsystem in qemu-kvm 0.14.0 and earlier allows privileged guest users to cause a denial of service (guest crash) or gain privileges via a crafted indirect descriptor related to "virtqueue in and out requests."
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Analysis
by VulDB Data Team • 12/04/2021
The vulnerability described in CVE-2011-2212 represents a critical buffer overflow condition within the virtio subsystem of qemu-kvm version 0.14.0 and earlier implementations. This flaw exists in the handling of indirect descriptors within virtqueue operations, specifically affecting the management of in and out requests that form the basis of virtualized I/O operations between guest operating systems and host hypervisors. The vulnerability impacts virtualized environments where multiple guest instances share the same host system, creating potential attack vectors that exploit the underlying virtualization infrastructure.
The technical exploitation of this buffer overflow occurs through the manipulation of indirect descriptor chains that are used to manage scatter-gather I/O operations in the virtio framework. When a privileged guest user crafts malicious indirect descriptors, the system fails to properly validate the size and structure of these descriptor chains, leading to memory corruption within the hypervisor's memory space. This memory corruption can manifest as either a controlled denial of service through guest crash scenarios or more severe privilege escalation attacks that allow the guest user to execute arbitrary code with host-level privileges. The vulnerability is particularly dangerous because it leverages the trusted relationship between guest and host within virtualized environments, where guest users typically have limited privileges but can exploit this flaw to gain elevated access.
The operational impact of this vulnerability extends beyond simple system availability issues to encompass potential data compromise and system integrity violations in virtualized environments. Organizations running virtualized infrastructure using affected qemu-kvm versions face significant risks including unauthorized privilege escalation, persistent access to host resources, and potential compromise of the entire virtualization cluster. The vulnerability affects the core I/O virtualization mechanism that underpins most modern cloud computing and virtual desktop infrastructures, making it a critical concern for enterprise environments that rely heavily on virtualization technologies. Security researchers have classified this vulnerability as having a high severity impact due to its potential for privilege escalation and the widespread adoption of affected qemu-kvm versions in production environments.
Mitigation strategies for CVE-2011-2212 require immediate patching of affected qemu-kvm installations to version 0.14.1 or later, which includes the necessary memory validation fixes for indirect descriptor handling. Organizations should also implement network segmentation and access controls to limit the ability of potentially malicious guest users to exploit this vulnerability, while monitoring for unusual system behavior that might indicate exploitation attempts. Additional defensive measures include disabling unnecessary virtio devices when not required, implementing strict guest user privilege controls, and conducting regular vulnerability assessments of virtualization infrastructure. This vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and represents a classic example of how virtualization layer flaws can create severe security implications that extend beyond traditional operating system boundaries. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the hypervisor layer to achieve system-level access, making it a critical concern for organizations implementing virtualized security architectures.