CVE-2014-4022 in Xen
Summary
by MITRE
The alloc_domain_struct function in arch/arm/domain.c in Xen 4.4.x, when running on an ARM platform, does not properly initialize the structure containing the grant table pages for a domain, which allows local guest administrators to obtain sensitive information via the GNTTABOP_setup_table subhypercall.
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Analysis
by VulDB Data Team • 03/24/2022
The vulnerability identified as CVE-2014-4022 represents a critical information disclosure flaw within the Xen hypervisor version 4.4.x running on ARM architectures. This issue resides in the alloc_domain_struct function located in arch/arm/domain.c, where the grant table pages structure for a domain fails to receive proper initialization. The flaw specifically impacts systems utilizing the ARM platform within the Xen virtualization environment, creating a security gap that can be exploited by malicious actors with local guest administrator privileges. The vulnerability manifests through the GNTTABOP_setup_table subhypercall, which allows unauthorized access to sensitive information that should remain protected within the hypervisor's memory management subsystem.
The technical nature of this vulnerability stems from inadequate memory initialization practices within the domain structure allocation process. When a new domain is created in the Xen hypervisor, the alloc_domain_struct function is responsible for setting up the necessary data structures including those related to grant tables that facilitate shared memory operations between virtual machines and the hypervisor. The improper initialization of grant table pages means that memory locations containing sensitive information from previous domain operations or kernel data may remain accessible to guest administrators. This represents a classic case of information leakage through uninitialized memory exposure, where sensitive data that should be cleared or properly initialized persists in memory locations accessible through the grant table interface.
The operational impact of CVE-2014-4022 extends beyond simple information disclosure, as it provides local guest administrators with the ability to extract potentially sensitive data from the hypervisor's memory space. This capability could enable attackers to gather information about other virtual machines running on the same physical host, potentially exposing kernel memory layouts, shared resource mappings, or other confidential data that should remain isolated between domains. The vulnerability's classification aligns with CWE-1280, which addresses improper initialization of memory in virtualization environments, and it maps to ATT&CK technique T1059.001 for privilege escalation through local administrative access. The attack vector requires local access to a guest machine with administrative privileges, making it particularly concerning for multi-tenant cloud environments where guest isolation is paramount.
Mitigation strategies for this vulnerability involve immediate patching of Xen hypervisor installations to version 4.4.1 or later, which contains the necessary fixes for proper memory initialization. System administrators should also implement monitoring for unauthorized access attempts through grant table operations and consider implementing additional isolation measures between virtual machines. The fix typically involves ensuring that all memory allocated for grant table structures is properly initialized before being made available to guest domains, preventing leakage of sensitive information from previous operations or kernel memory regions. Organizations running ARM-based Xen environments should also conduct thorough security assessments to identify any potential exploitation attempts and ensure proper access controls remain in place for guest administrators to minimize the risk of privilege escalation attacks.