CVE-2010-0298 in Linux
Summary
by MITRE
The x86 emulator in KVM 83 does not use the Current Privilege Level (CPL) and I/O Privilege Level (IOPL) in determining the memory access available to CPL3 code, which allows guest OS users to cause a denial of service (guest OS crash) or gain privileges on the guest OS by leveraging access to a (1) IO port or (2) MMIO region, a related issue to CVE-2010-0306.
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Analysis
by VulDB Data Team • 06/28/2024
The vulnerability described in CVE-2010-0298 represents a critical flaw in the kernel-based virtual machine (KVM) implementation that affects virtualized environments running on x86 architectures. This issue specifically targets the x86 emulator component within KVM version 83, where the emulator fails to properly enforce privilege level checks that are fundamental to x86 architecture security. The vulnerability stems from the emulator's inability to correctly utilize the Current Privilege Level (CPL) and I/O Privilege Level (IOPL) fields when evaluating memory access permissions for code executing at CPL3, which represents the least privileged ring level in x86 architecture. This deficiency creates a security boundary violation that undermines the fundamental isolation mechanisms that virtualization platforms rely upon to maintain guest OS security.
The technical flaw manifests when guest operating systems attempt to access I/O ports or MMIO (memory-mapped I/O) regions through the KVM emulator. Under normal circumstances, x86 architecture enforces strict privilege checks where CPL3 code should be restricted from accessing certain memory regions and I/O operations that are typically reserved for kernel-level processes. However, the KVM emulator's failure to properly consider CPL and IOPL values means that malicious or compromised guest code can bypass these essential access controls. When CPL3 code attempts to perform I/O operations or access MMIO regions, the emulator incorrectly grants access privileges that should be denied, potentially allowing unauthorized memory access patterns. This vulnerability operates at the intersection of virtualization security and hardware privilege enforcement, creating a pathway for privilege escalation attacks.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass potential privilege escalation within virtualized environments. Attackers can leverage this flaw to cause guest OS crashes through malformed I/O port access attempts or more seriously, to gain elevated privileges within the guest operating system. The vulnerability affects virtualized environments where multiple guest operating systems run on the same host, potentially allowing an attacker in one guest to compromise the security of other guests or even the host system itself. This type of vulnerability is particularly concerning in cloud computing environments where virtualization is the foundation of multi-tenant security models, as it could enable cross-tenant attacks that undermine the isolation guarantees that virtualization platforms are designed to provide.
From a cybersecurity perspective, this vulnerability aligns with CWE-254 and CWE-255 categories that address security weaknesses in privilege management and access control mechanisms. The flaw demonstrates how virtualization platforms can introduce new attack surfaces that are not present in traditional bare-metal systems, particularly when emulator components fail to implement full architectural compliance. The relationship to CVE-2010-0306 indicates that this represents part of a broader class of virtualization security issues where emulator implementations do not fully respect x86 privilege levels, creating consistent security gaps across different virtualization components. Organizations implementing KVM-based virtualization should consider this vulnerability as part of their broader virtualization security posture assessment, particularly in environments where guest isolation is critical for security compliance.
Mitigation strategies for CVE-2010-0298 should include immediate patching of affected KVM versions to ensure proper CPL and IOPL handling within the x86 emulator. System administrators should also implement monitoring for suspicious I/O port access patterns and MMIO region usage that might indicate exploitation attempts. Network segmentation and guest OS hardening measures can help reduce the potential impact of successful exploitation attempts, while regular vulnerability assessments of virtualization infrastructure should be conducted to identify similar privilege enforcement issues. The vulnerability underscores the importance of thorough security testing for virtualization components and highlights the need for continuous security auditing of emulator implementations that directly interface with hardware privilege mechanisms.