CVE-2015-3340 in Xen
Summary
by MITRE
Xen 4.2.x through 4.5.x does not initialize certain fields, which allows certain remote service domains to obtain sensitive information from memory via a (1) XEN_DOMCTL_gettscinfo or (2) XEN_SYSCTL_getdomaininfolist request.
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Analysis
by VulDB Data Team • 05/09/2022
The vulnerability identified as CVE-2015-3340 affects Xen hypervisor versions 4.2.x through 4.5.x and represents a critical information disclosure flaw that stems from inadequate memory initialization practices within the hypervisor's control interfaces. This vulnerability specifically impacts two key system calls: XEN_DOMCTL_gettscinfo and XEN_SYSCTL_getdomaininfolist, which are essential components for domain management and system information retrieval within virtualized environments. The flaw allows remote service domains to exploit improperly initialized memory fields and extract sensitive information from the hypervisor's memory space, potentially compromising the integrity and confidentiality of the entire virtualization infrastructure.
The technical root cause of this vulnerability lies in the hypervisor's failure to properly initialize certain memory fields during the processing of control requests. When remote domains submit requests through the affected system calls, the hypervisor does not adequately clear or initialize specific memory regions before returning information to the requesting domain. This memory leakage occurs because the implementation does not follow proper secure coding practices that would ensure all memory locations are properly sanitized before data is returned to userspace. The uninitialized memory fields may contain remnants of previous operations, sensitive configuration data, or other confidential information from other domains or system components, creating a significant information disclosure vector that can be exploited by malicious actors.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially enable more sophisticated attacks within virtualized environments. Attackers who can successfully exploit this vulnerability gain access to sensitive memory contents that may include domain-specific information, system configuration details, or other confidential data that could be leveraged for further exploitation. This information leakage can compromise the isolation guarantees that virtualization platforms are designed to provide, potentially allowing one domain to access data belonging to other domains or even the host system itself. The vulnerability is particularly concerning in multi-tenant environments where multiple customers share the same hypervisor infrastructure, as it could enable cross-tenant data leakage and violate fundamental security principles of virtualization.
Mitigation strategies for CVE-2015-3340 should focus on immediate patching of affected Xen versions, with organizations upgrading to versions that properly initialize memory fields before processing control requests. System administrators should also implement monitoring solutions to detect anomalous behavior in hypervisor interfaces and consider network segmentation to limit access to hypervisor control interfaces. The vulnerability aligns with CWE-119, which addresses improper access to memory locations, and can be mapped to ATT&CK technique T1059 for privilege escalation through hypervisor manipulation. Organizations should also conduct thorough security assessments of their virtualization environments to identify potential exploitation vectors and ensure proper memory management practices are implemented across all hypervisor components. The remediation process should include comprehensive testing to verify that memory initialization occurs correctly and that no residual sensitive data remains accessible through the affected system calls.