CVE-2010-0730 in Enterprise Linux Desktop
Summary
by MITRE
The MMIO instruction decoder in the Xen hypervisor in the Linux kernel 2.6.18 in Red Hat Enterprise Linux (RHEL) 5 allows guest OS users to cause a denial of service (32-bit guest OS crash) via vectors that trigger an unspecified instruction emulation.
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Analysis
by VulDB Data Team • 09/13/2021
The vulnerability identified as CVE-2010-0730 represents a critical flaw in the Xen hypervisor's memory-mapped I/O instruction decoder implementation within the Linux kernel 2.6.18 running on Red Hat Enterprise Linux 5 systems. This weakness specifically affects 32-bit guest operating systems that are managed by the Xen virtualization platform, creating a potential vector for malicious actors to disrupt normal system operations. The vulnerability stems from inadequate handling of certain instruction emulation scenarios that occur when guest operating systems attempt to execute memory-mapped I/O operations, leading to unexpected system behavior and potential service disruption.
The technical flaw manifests in the hypervisor's instruction decoding mechanism where specific MMIO instructions trigger an unspecified instruction emulation process that fails to properly handle error conditions or edge cases. When a guest OS user executes particular memory-mapped I/O operations, the hypervisor's decoder encounters a scenario that causes it to either crash or enter an unstable state, resulting in the complete termination of the 32-bit guest operating system. This represents a classic denial of service vulnerability where legitimate system operations are disrupted through carefully crafted instruction sequences that exploit the hypervisor's insufficient error handling capabilities. The vulnerability falls under the CWE-248 category of Unhandled Exception, specifically involving improper handling of instruction emulation failures within virtualization environments.
The operational impact of this vulnerability extends beyond simple system crashes, as it enables malicious users within a guest OS to effectively disrupt the service availability of their virtual machine and potentially impact the broader virtualization infrastructure. Since the vulnerability affects the hypervisor layer itself, any guest user with sufficient privileges can exploit this weakness to cause system instability, leading to unauthorized denial of service conditions that may affect multiple virtual machines sharing the same physical host. This creates significant security implications for cloud computing environments and virtualized data centers where multiple tenants operate on shared infrastructure, as a single compromised guest could potentially disrupt services for other users. The vulnerability also represents a potential stepping stone for more sophisticated attacks that could leverage the instability to escalate privileges or execute further malicious code within the virtualized environment.
Mitigation strategies for CVE-2010-0730 should focus on immediate patching of the affected Xen hypervisor versions, with administrators prioritizing updates to the Linux kernel 2.6.18 and related virtualization components. Organizations should implement monitoring systems to detect anomalous instruction execution patterns that might indicate exploitation attempts, particularly focusing on memory-mapped I/O operations within virtualized environments. The ATT&CK framework categorizes this vulnerability under the T1499.004 technique for Network Denial of Service, as it enables attackers to disrupt system availability through hypervisor-level vulnerabilities. Additionally, system administrators should consider implementing virtual machine isolation measures and privilege controls to limit the potential impact of compromised guest operating systems, while also ensuring that all virtualization components are regularly updated to address known vulnerabilities. The vulnerability underscores the importance of maintaining up-to-date virtualization infrastructure and proper security hygiene in multi-tenant computing environments where hypervisor-level security is paramount to overall system integrity.