CVE-2014-0147 in QEMU
Summary
by MITRE • 09/29/2022
Qemu before 1.6.2 block diver for the various disk image formats used by Bochs and for the QCOW version 2 format, are vulnerable to a possible crash caused by signed data types or a logic error while creating QCOW2 snapshots, which leads to incorrectly calling update_refcount() routine.
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Analysis
by VulDB Data Team • 09/29/2022
The vulnerability identified as CVE-2014-0147 affects QEMU versions prior to 1.6.2 and specifically targets the block driver component responsible for handling disk image formats used by Bochs and QCOW version 2. This issue represents a critical flaw in the virtualization infrastructure that could lead to denial of service conditions and potentially more severe consequences within virtualized environments. The vulnerability stems from improper handling of signed data types during the creation of QCOW2 snapshots, which creates a scenario where the update_refcount() routine is called incorrectly, leading to system instability and potential crashes.
The technical root cause of this vulnerability lies in the manipulation of signed integer data types within the QCOW2 snapshot creation process. When QEMU processes disk image formats, particularly those compatible with Bochs and QCOW2, it performs operations that involve signed integer arithmetic. The flaw occurs when these signed values are improperly converted or compared, resulting in unexpected behavior that triggers incorrect function calls. This type of error falls under the CWE-190 category of Integer Overflow or Wraparound, where the signed integer operations produce values that exceed the expected range, causing the system to execute unintended code paths. The specific manifestation involves the update_refcount() routine being invoked with invalid parameters, leading to memory corruption and system instability.
The operational impact of this vulnerability extends beyond simple system crashes, as it can severely affect virtualized environments where QEMU serves as the primary virtualization platform. Attackers who can influence the creation of QCOW2 snapshots or manipulate disk image formats may exploit this vulnerability to cause denial of service conditions, potentially disrupting critical virtual machines and the services they host. In enterprise environments where virtualization is extensively used, such an exploit could lead to widespread service disruptions and compromise the availability of virtualized applications. The vulnerability is particularly concerning in cloud computing environments where multiple virtual machines share underlying physical resources, as a single compromised VM could potentially affect the entire host system.
Mitigation strategies for CVE-2014-0147 should prioritize immediate patching of QEMU installations to version 1.6.2 or later, which contains the necessary fixes for the signed integer handling issues. Organizations should also implement monitoring systems to detect unusual disk image creation patterns or snapshot operations that might indicate exploitation attempts. Additionally, virtualization administrators should consider implementing network segmentation and access controls to limit who can create or modify disk images within virtualized environments. The ATT&CK framework categorizes this vulnerability under the T1499.004 technique for Network Denial of Service, as the exploitation can lead to service disruption. Security teams should also perform regular vulnerability assessments of virtualization components and maintain up-to-date threat intelligence to identify potential exploitation attempts targeting similar integer overflow vulnerabilities in other virtualization platforms.