CVE-2012-1515 in Windows
Summary
by MITRE
VMware ESXi 3.5, 4.0, and 4.1 and ESX 3.5, 4.0, and 4.1 do not properly implement port-based I/O operations, which allows guest OS users to gain guest OS privileges by overwriting memory locations in a read-only memory block associated with the Virtual DOS Machine.
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Analysis
by VulDB Data Team • 01/07/2025
This vulnerability affects VMware ESXi and ESX hypervisors across multiple versions including 3.5, 4.0, and 4.1, representing a critical privilege escalation flaw that undermines the fundamental security model of virtualized environments. The vulnerability stems from improper implementation of port-based I/O operations within the hypervisor's virtual machine monitor component. When guest operating systems attempt to perform I/O operations through specific port addresses, the hypervisor fails to properly validate or restrict these operations, creating an exploitable condition that allows malicious guest users to manipulate memory structures that should remain protected.
The technical flaw manifests when guest operating systems attempt to write to memory locations that are designated as read-only within the Virtual DOS Machine context. This occurs because the hypervisor's port I/O handling mechanism does not adequately enforce memory protection boundaries, particularly when dealing with legacy DOS compatibility modes. The vulnerability specifically targets the Virtual DOS Machine implementation where certain memory regions are supposed to be immutable but can be overwritten through crafted port I/O operations. This memory corruption allows attackers to escalate privileges from guest OS level to host OS level, effectively breaking the isolation that separates virtual machines from each other and from the underlying hypervisor.
The operational impact of this vulnerability is severe as it enables attackers with access to a guest operating system to achieve full control over the host hypervisor, potentially compromising all virtual machines running on the same host. This privilege escalation allows for complete data theft, system compromise, and the ability to launch further attacks against other virtual machines or the physical infrastructure. The vulnerability is particularly dangerous in multi-tenant environments where multiple customers share the same physical hardware, as a single compromised guest can potentially affect the entire infrastructure. According to CWE classification, this represents a weakness in the implementation of memory protection mechanisms, specifically CWE-248, which deals with an exception being thrown from a constructor or destructor, but in this case it manifests through improper I/O port handling. The vulnerability aligns with ATT&CK technique T1055 which covers privilege escalation through exploitation of software vulnerabilities.
Mitigation strategies should include immediate patching of affected VMware products to address the port I/O validation issues in the hypervisor. Organizations should also implement network segmentation and monitoring to detect unusual I/O patterns that might indicate exploitation attempts. Additional protective measures include disabling unnecessary legacy compatibility modes, implementing strict access controls for virtual machine configurations, and maintaining comprehensive logging of hypervisor activities. Regular security assessments and vulnerability scanning of virtualized environments should be conducted to identify similar implementation flaws. The vulnerability highlights the importance of rigorous input validation in hypervisor components and demonstrates how seemingly minor implementation details in low-level system operations can create critical security risks that affect entire virtualization infrastructures.