CVE-2011-1750 in qemu
Summary
by MITRE
Multiple heap-based buffer overflows in the virtio-blk driver (hw/virtio-blk.c) in qemu-kvm 0.14.0 allow local guest users to cause a denial of service (guest crash) and possibly gain privileges via a (1) write request to the virtio_blk_handle_write function or (2) read request to the virtio_blk_handle_read function that is not properly aligned.
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Analysis
by VulDB Data Team • 12/04/2021
The vulnerability identified as CVE-2011-1750 represents a critical heap-based buffer overflow in the virtio-blk driver component of qemu-kvm version 0.14.0. This issue affects virtualized environments where guest operating systems communicate with virtual block devices through the virtio interface. The flaw exists within the hardware virtualization layer that enables communication between the guest and host systems, specifically in how the driver handles read and write operations to virtual block devices. The vulnerability manifests when guest users submit improperly aligned read or write requests to virtual block devices, creating conditions where the driver fails to properly validate buffer boundaries during data processing. This type of vulnerability falls under CWE-121, which describes heap-based buffer overflow conditions, and specifically relates to improper input validation and memory management in virtualized environments.
The technical execution of this vulnerability occurs through the virtio_blk_handle_write and virtio_blk_handle_read functions within the hw/virtio-blk.c source file. When a guest user submits a write request to a virtual block device, the driver processes the request without adequate bounds checking on the data buffer, allowing malicious input to overwrite adjacent heap memory regions. Similarly, read operations fail to properly validate alignment requirements, creating opportunities for buffer overflows that can corrupt memory structures. The improper alignment handling particularly targets the virtual block device's data transfer mechanisms, where guest operating systems submit I/O requests that the hypervisor processes through the virtio-blk driver. This flaw enables attackers to manipulate memory layout and potentially overwrite critical data structures, leading to system instability and potential privilege escalation.
The operational impact of CVE-2011-1750 extends beyond simple denial of service conditions to potentially enable privilege escalation within virtualized environments. Local guest users can leverage this vulnerability to cause guest system crashes, effectively creating a denial of service condition that disrupts virtual machine operations. More critically, the heap corruption resulting from these buffer overflows could potentially be exploited to execute arbitrary code within the guest context, particularly if the attacker can control the data being written to the vulnerable buffer. The vulnerability affects the stability of virtualized environments where multiple guests share the same host system, potentially allowing one compromised guest to affect other virtual machines running on the same physical hardware. This represents a significant concern for cloud computing environments and virtualized infrastructure where guest isolation is paramount for security.
Mitigation strategies for CVE-2011-1750 should focus on immediate patching of qemu-kvm installations to versions that address the buffer overflow conditions in the virtio-blk driver. System administrators must ensure that all virtualization hosts are updated to patched versions that properly validate input alignment and implement robust bounds checking in the virtio-blk handling functions. Additionally, implementing virtual machine isolation measures and monitoring for anomalous I/O patterns can help detect exploitation attempts. Network segmentation and access controls should be enforced to limit guest user privileges and reduce the attack surface. The vulnerability demonstrates the importance of input validation in hypervisor components and aligns with ATT&CK technique T1059.001 for privilege escalation through memory corruption. Organizations should also consider implementing runtime protection mechanisms and regular security assessments of virtualization infrastructure to identify similar vulnerabilities in other hypervisor components and prevent exploitation of similar memory corruption flaws.