CVE-2013-5651 in libvirt
Summary
by MITRE
The virBitmapParse function in util/virbitmap.c in libvirt before 1.1.2 allows context-dependent attackers to cause a denial of service (out-of-bounds read and crash) via a crafted bitmap, as demonstrated by a large nodeset value to numatune.
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Analysis
by VulDB Data Team • 01/08/2022
The vulnerability identified as CVE-2013-5651 resides within the libvirt virtualization management library, specifically in the virBitmapParse function located in util/virbitmap.c. This flaw represents a classic buffer over-read condition that occurs when processing crafted bitmap data structures. The vulnerability affects libvirt versions prior to 1.1.2, making it a significant concern for systems utilizing older virtualization frameworks. The issue manifests when the function encounters a malformed bitmap with an excessive nodeset value during numatune operations, which are used to configure NUMA (Non-Uniform Memory Access) placement for virtual machines.
The technical exploitation of this vulnerability involves an attacker crafting a malicious bitmap structure that contains an abnormally large nodeset value, which then triggers an out-of-bounds memory read during the parsing process. This occurs because the virBitmapParse function fails to properly validate the size constraints of the input bitmap data before attempting to process it. The function does not adequately check the boundaries of the nodeset value against the allocated memory space, leading to memory access violations that result in application crashes. This type of vulnerability falls under CWE-129, which specifically addresses insufficient validation of length of inputs, and represents a direct consequence of inadequate input sanitization and boundary checking mechanisms.
From an operational perspective, this vulnerability poses a significant denial of service risk to virtualization environments that rely on libvirt for management operations. When exploited, the out-of-bounds read causes the libvirt daemon to crash, effectively disrupting virtual machine management services and potentially leading to service interruptions for all virtualized workloads managed by the affected system. The impact extends beyond simple service disruption as it can compromise the stability of entire virtualization platforms, affecting multiple virtual machines simultaneously. Attackers can leverage this vulnerability to systematically destabilize virtualization infrastructure, making it particularly dangerous in enterprise environments where high availability and consistent service delivery are critical requirements.
The attack surface for this vulnerability is primarily limited to systems running vulnerable versions of libvirt where numatune operations are performed, typically in virtualized environments with NUMA-aware configurations. The ATT&CK framework categorizes this as a privilege escalation technique through resource exhaustion and system instability, though in this case it manifests as a denial of service rather than unauthorized access. Organizations should implement immediate mitigations including upgrading to libvirt version 1.1.2 or later, which contains the necessary patches to properly validate bitmap input sizes and prevent the out-of-bounds memory access. Additionally, deploying input validation controls and monitoring for unusual numatune operations can help detect potential exploitation attempts and provide early warning of attempted attacks against the virtualization infrastructure.