CVE-2015-0236 in libvirt
Summary
by MITRE
libvirt before 1.2.12 allow remote authenticated users to obtain the VNC password by using the VIR_DOMAIN_XML_SECURE flag with a crafted (1) snapshot to the virDomainSnapshotGetXMLDesc interface or (2) image to the virDomainSaveImageGetXMLDesc interface.
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Analysis
by VulDB Data Team • 03/10/2022
The vulnerability identified as CVE-2015-0236 represents a critical security flaw within the libvirt virtualization management library that affects versions prior to 1.2.12. This issue resides in the way libvirt handles XML description requests for domain snapshots and save images, specifically when the VIR_DOMAIN_XML_SECURE flag is utilized. The vulnerability stems from insufficient input validation and improper handling of sensitive data within the XML processing functions, creating a pathway for authenticated remote attackers to extract VNC passwords from virtual machine configurations.
The technical implementation of this vulnerability occurs through the manipulation of the virDomainSnapshotGetXMLDesc and virDomainSaveImageGetXMLDesc API functions. When an authenticated user invokes these interfaces with the VIR_DOMAIN_XML_SECURE flag, the libvirt library fails to properly sanitize or filter the XML output, allowing sensitive information to be exposed in the returned XML structure. This flaw specifically impacts the handling of snapshot and save image data where VNC passwords are stored within the domain configuration XML, making them accessible to attackers who can craft malicious requests to these interfaces.
From an operational impact perspective, this vulnerability significantly compromises the security posture of virtualized environments managed by libvirt. Remote authenticated attackers can leverage this weakness to obtain VNC passwords, which typically provide direct console access to virtual machines. This access can lead to complete system compromise, data exfiltration, and lateral movement within the virtualized infrastructure. The vulnerability affects any system running libvirt versions before 1.2.12 where virtual machines are configured with VNC access and snapshot functionality is enabled, making it particularly dangerous in enterprise virtualization environments.
The vulnerability aligns with CWE-200, which describes improper exposure of sensitive information, and represents a clear violation of information security principles. It also maps to ATT&CK technique T1003.002 for OS Credential Dumping, as the extracted VNC passwords can be used to gain unauthorized access to virtual machine consoles. Organizations using libvirt for virtual machine management should prioritize immediate patching to version 1.2.12 or later, as this vulnerability can be exploited remotely by authenticated users who have access to the libvirt management interface. Additional mitigations include restricting network access to libvirt management interfaces, implementing proper access controls, and monitoring for unusual XML description requests that may indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation and secure output handling in virtualization management systems, particularly when dealing with sensitive authentication credentials stored in configuration data structures.