CVE-2005-0204 in Linux
Summary
by MITRE
linux kernel before 2.6.9 when running on the amd64 and intel em64t architectures allows local users to write to privileged io ports via the outs instruction.
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Analysis
by VulDB Data Team • 05/31/2019
The vulnerability described in CVE-2005-0204 represents a critical privilege escalation flaw within the linux kernel version 2.6.9 and earlier, specifically affecting systems utilizing amd64 and intel em64t processor architectures. This issue stems from inadequate kernel security controls that fail to properly validate input when processing the outs instruction, which is used for output operations to I/O ports. The flaw exists in the kernel's handling of privileged I/O port access mechanisms, creating an avenue for local attackers to bypass normal security boundaries and gain unauthorized access to system resources that should be restricted to kernel-level operations.
The technical implementation of this vulnerability involves the improper validation of I/O port operations within the kernel's system call handling routines. When a local user executes the outs instruction on affected systems, the kernel fails to properly verify whether the operation should be permitted based on the current security context. This weakness is particularly severe because it operates at the kernel level, allowing users to directly manipulate hardware I/O ports that typically require kernel privileges or root access. The vulnerability manifests through the kernel's failure to implement proper access control checks when processing output operations to I/O ports, specifically targeting the architecture-specific I/O port handling code paths used in 64-bit x86 environments.
From an operational impact perspective, this vulnerability creates a significant risk for systems running affected kernel versions, as local users can potentially escalate their privileges to root level access. The attack vector requires local system access but does not necessitate network connectivity or specialized equipment, making it particularly dangerous in multi-user environments where users might have limited access to system resources. Successful exploitation could enable attackers to read sensitive system information, modify kernel data structures, disable security features, or gain complete system control. The vulnerability affects systems where the kernel lacks proper I/O port validation, particularly impacting enterprise servers, desktop systems, and virtualized environments running these older kernel versions.
The security implications of CVE-2005-0204 align with CWE-284, which addresses improper access control in software systems, and can be mapped to ATT&CK technique T1068, which involves exploiting vulnerabilities to gain system privileges. Organizations should prioritize immediate patching of affected systems to address this vulnerability, as the kernel version 2.6.9 and earlier contain multiple security flaws that compound the risk. Mitigation strategies include implementing kernel lockdown mechanisms, disabling unnecessary I/O port access capabilities, and maintaining up-to-date system configurations with proper access controls. System administrators should also consider implementing monitoring solutions to detect suspicious I/O port access patterns and ensure that all systems are running patched kernel versions that address this specific vulnerability through proper input validation and access control enforcement.