CVE-2014-0223 in QEMU
Summary
by MITRE
Integer overflow in the qcow_open function in block/qcow.c in QEMU before 1.7.2 allows local users to cause a denial of service (crash) and possibly execute arbitrary code via a large image size, which triggers a buffer overflow or out-of-bounds read.
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Analysis
by VulDB Data Team • 06/19/2021
The vulnerability described in CVE-2014-0223 represents a critical integer overflow flaw within the QEMU virtualization platform's block driver implementation. This issue affects QEMU versions prior to 1.7.2 and resides in the qcow_open function located in block/qcow.c. The vulnerability stems from inadequate input validation when processing qcow image files, specifically when handling large image sizes that exceed the bounds of standard integer data types. When a maliciously crafted qcow image file is processed, the integer overflow condition causes the system to miscalculate memory allocation requirements, leading to either buffer overflow conditions or out-of-bounds memory reads.
The technical exploitation of this vulnerability occurs through the manipulation of qcow image file headers where the image size field contains a value that, when processed, causes integer overflow during calculations. This flaw falls under the CWE-190 category of Integer Overflow or Wraparound, which is a well-documented weakness in software security. The qcow format is a popular virtual disk image format used in QEMU virtual machines, making this vulnerability particularly dangerous as it can be triggered when any virtual machine attempts to load a malicious qcow image file. The integer overflow condition in the qcow_open function creates a scenario where the calculated buffer size becomes negative or exceeds maximum allowable values, resulting in unpredictable memory access patterns.
The operational impact of CVE-2014-0223 extends beyond simple denial of service to potentially enable arbitrary code execution, making it a severe security concern for virtualization environments. Local attackers who can influence the creation or modification of qcow image files can trigger the vulnerability by crafting specially designed image files with oversized size parameters. This vulnerability directly maps to the ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1499.004 for Endpoint Denial of Service, as it can be leveraged to crash virtual machines or potentially execute malicious code within the host system. The vulnerability affects systems running QEMU versions before 1.7.2, which were widely deployed in cloud environments, virtualization platforms, and development systems, amplifying the potential attack surface.
Mitigation strategies for this vulnerability require immediate patching of QEMU installations to version 1.7.2 or later, where the integer overflow has been addressed through proper input validation and boundary checking. System administrators should implement strict file validation policies for qcow image files, particularly in multi-tenant environments where untrusted users might upload virtual disk images. The fix involves adding comprehensive input validation checks to ensure that image size parameters remain within acceptable ranges before any memory allocation occurs. Additionally, organizations should consider implementing virtualization security measures such as mandatory access controls, sandboxing of virtual machine image processing, and network segmentation to limit potential exploitation. Security monitoring should be enhanced to detect unusual qcow image file access patterns and suspicious memory allocation behaviors that might indicate exploitation attempts. The vulnerability highlights the importance of robust input validation in virtualization software and serves as a reminder of the critical security considerations in hypervisor implementations.