CVE-2014-3717 in Xen
Summary
by MITRE
Xen 4.4.x does not properly validate the load address for 64-bit ARM guest kernels, which allows local users to read system memory or cause a denial of service (crash) via a crafted kernel, which triggers a buffer overflow.
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Analysis
by VulDB Data Team • 03/21/2022
The vulnerability identified as CVE-2014-3717 affects Xen hypervisor versions 4.4.x and represents a critical validation flaw in the ARM architecture support for 64-bit guest kernels. This issue stems from insufficient input validation mechanisms within the hypervisor's kernel loading process, specifically targeting the load address validation for ARM64 guest operating systems. The vulnerability exists at the intersection of virtualization security and kernel integrity, where the hypervisor fails to properly verify the memory addresses specified during kernel loading operations.
The technical flaw manifests as a failure in the hypervisor's address validation routine, which should enforce proper memory boundaries and alignment constraints for 64-bit ARM guest kernels. When a malicious local user presents a crafted kernel image with an improperly validated load address, the hypervisor's memory management subsystem becomes vulnerable to exploitation. This validation failure creates a condition where the system processes memory addresses without adequate bounds checking, leading to potential buffer overflow conditions that can be leveraged for arbitrary memory access or system instability.
From an operational perspective, this vulnerability presents significant risks to virtualized environments running ARM64 guest operating systems. Local attackers with access to the virtual machine can exploit this weakness to read arbitrary system memory locations, potentially extracting sensitive data or credentials stored in memory. The vulnerability also enables denial of service attacks that can crash the entire virtual machine or hypervisor instance, leading to service disruption and potential data loss. The impact extends beyond individual VMs to affect the overall stability and security posture of the virtualization infrastructure.
The exploitation of this vulnerability aligns with attack patterns documented in the MITRE ATT&CK framework under the technique of privilege escalation and defense evasion. Specifically, it relates to the use of kernel exploits and memory corruption techniques that allow attackers to bypass normal access controls. The vulnerability's classification as a buffer overflow aligns with CWE-121, which describes conditions where insufficient bounds checking leads to memory corruption. Additionally, this issue demonstrates weaknesses in the hypervisor's input validation mechanisms, which should be addressed through proper validation of all guest kernel parameters.
Mitigation strategies for CVE-2014-3717 primarily involve upgrading to Xen hypervisor versions that contain the necessary patches and validation fixes for ARM64 guest kernel loading. System administrators should implement immediate patch management procedures to address this vulnerability across all affected virtualization environments. Additional protective measures include implementing strict access controls to prevent unauthorized local access to virtual machines, monitoring for suspicious kernel loading activities, and maintaining comprehensive system logging to detect potential exploitation attempts. Organizations should also consider implementing virtualization security solutions that can detect and prevent unauthorized memory access patterns associated with this class of vulnerability.