CVE-2010-3851 in libguestfs
Summary
by MITRE
libguestfs before 1.5.23, as used in virt-v2v, virt-inspector 1.5.3 and earlier, and possibly other products, when a raw-format disk image is used, allows local guest OS administrators to read files from the host via a crafted (1) qcow2, (2) VMDK, or (3) VDI header, related to lack of support for a disk format specifier.
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Analysis
by VulDB Data Team • 01/20/2025
The vulnerability described in CVE-2010-3851 represents a critical security flaw in libguestfs versions prior to 1.5.23 that affects virtualization tools including virt-v2v and virt-inspector. This issue stems from insufficient validation of disk image formats when processing raw-format disk images, creating a pathway for privilege escalation and information disclosure. The vulnerability specifically impacts systems where guest operating systems have administrative access to virtual machines, allowing them to exploit the lack of proper format specifier handling in the underlying disk image processing libraries.
The technical root cause of this vulnerability lies in the absence of proper disk format validation within libguestfs when handling raw-format disk images. When a guest OS administrator has access to a virtual machine running on a host system, they can craft malicious disk headers in qcow2, VMDK, or VDI formats that bypass normal security boundaries. This occurs because the library fails to properly validate or reject disk image formats that contain malicious headers, enabling the guest to read files from the host operating system. The flaw essentially allows for a form of cross-contamination between guest and host environments through the disk image processing layer.
The operational impact of this vulnerability is significant as it enables local guest administrators to perform unauthorized file reads from the host system, potentially exposing sensitive data, configuration files, or system resources. Attackers could leverage this to extract credentials, system configuration information, or other confidential data that should remain isolated between guest and host environments. This represents a serious breach of virtualization security principles where the isolation normally provided by virtual machines is compromised. The vulnerability affects multiple products in the virt-tools suite, making it particularly widespread in virtualization environments that utilize these tools for conversion and inspection operations.
This vulnerability maps to CWE-200 (Information Exposure) and CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) within the CWE taxonomy, representing information disclosure through improper handling of disk image formats. From an ATT&CK framework perspective, this maps to T1059 (Command and Scripting Interpreter) and T1005 (Data from Local System) as attackers can execute commands through the compromised disk image processing and extract local system data. The attack vector typically involves crafting malicious disk headers that exploit the lack of format validation, allowing the guest OS to access host resources through the libguestfs library. Mitigation strategies include updating to libguestfs version 1.5.23 or later, implementing strict disk image validation policies, and ensuring proper network segmentation to limit guest access privileges. Organizations should also consider implementing monitoring for suspicious disk image processing activities and conducting regular security assessments of virtualization environments to detect potential exploitation attempts.