CVE-2014-0179 in libvirt
Summary
by MITRE
libvirt 0.7.5 through 1.2.x before 1.2.5 allows local users to cause a denial of service (read block and hang) via a crafted XML document containing an XML external entity declaration in conjunction with an entity reference to the (1) virConnectCompareCPU or (2) virConnectBaselineCPU API method, related to an XML External Entity (XXE) issue. NOTE: this issue was SPLIT per ADT3 due to different affected versions of some vectors. CVE-2014-5177 is used for other API methods.
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Analysis
by VulDB Data Team • 06/19/2021
The vulnerability identified as CVE-2014-0179 represents a critical XML External Entity (XXE) flaw within the libvirt virtualization management library. This security issue affects libvirt versions ranging from 0.7.5 through 1.2.x before 1.2.5, creating a significant risk for systems utilizing this virtualization framework. The vulnerability specifically targets two API methods: virConnectCompareCPU and virConnectBaselineCPU, which are essential for CPU configuration and comparison operations in virtualized environments. The flaw stems from inadequate input validation mechanisms that fail to properly sanitize XML documents processed by these functions, allowing maliciously crafted XML content to exploit the system's XML parser.
The technical implementation of this vulnerability involves the exploitation of XML external entity processing within libvirt's API layer. When a local attacker submits a crafted XML document containing an XML external entity declaration, combined with an entity reference targeting the vulnerable API methods, the system attempts to resolve these external entities. This processing behavior creates a read block and system hang condition, effectively causing a denial of service attack that renders the virtualization management interface unavailable. The vulnerability operates at the parser level, where XML entities are resolved without proper restrictions, enabling attackers to access local resources or trigger resource exhaustion conditions. This XXE implementation follows the standard pattern described in CWE-611, which specifically addresses improper restriction of XML external entity references in XML parsers.
From an operational impact perspective, this vulnerability poses substantial risks to virtualized environments that rely on libvirt for management operations. The denial of service condition affects critical CPU comparison and baseline functionality, potentially disrupting virtual machine provisioning, migration, and configuration management processes. Local attackers with access to the system can exploit this vulnerability to cause system unavailability, which may result in business disruption and service degradation. The impact extends beyond simple availability issues since the vulnerability affects core virtualization management capabilities, potentially compromising the integrity of virtual machine configurations and the overall stability of the virtualized infrastructure. Organizations using affected libvirt versions face potential operational downtime and the need for immediate patching or workaround implementation.
Security practitioners should consider this vulnerability in relation to the ATT&CK framework's privilege escalation and denial of service tactics, as local users can leverage this flaw to disrupt system operations. The vulnerability's classification as an XXE issue places it within the broader context of web application security concerns, though it manifests within a system-level library rather than a web interface. Mitigation strategies should include immediate patching to libvirt version 1.2.5 or later, which addresses the XML parsing issues through proper entity validation and restriction. Additionally, administrators should implement strict XML input validation policies, disable external entity processing in XML parsers, and consider network segmentation to limit local access to vulnerable systems. System monitoring should be enhanced to detect unusual XML processing patterns that might indicate exploitation attempts, while regular security assessments should verify that all virtualization management interfaces properly handle XML input to prevent similar XXE vulnerabilities from emerging in other components.