CVE-2005-4789 in Linux
Summary
by MITRE
resmgr in SUSE Linux 9.2 and 9.3, and possibly other distributions, does not properly enforce class-specific exclude rules in some situations, which allows local users to bypass intended access restrictions for USB devices that set their class ID at the interface level.
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Analysis
by VulDB Data Team • 07/07/2021
The vulnerability described in CVE-2005-4789 represents a critical access control flaw within the resource manager component of SUSE Linux distributions version 9.2 and 9.3, with potential impacts extending to other Linux distributions. This issue specifically targets the USB device management system where the resmgr service fails to properly enforce class-specific exclusion rules under certain conditions. The flaw exists at the interface level of USB device class identification, creating a pathway for unauthorized access that bypasses intended security controls designed to restrict USB device access based on their class identifiers.
The technical implementation of this vulnerability stems from improper validation within the USB device resource management subsystem. When USB devices are connected to systems running affected SUSE Linux versions, the resmgr component should enforce specific exclusion rules based on device class IDs assigned at the interface level. However, due to flawed logic in the access control enforcement mechanism, local users can manipulate or exploit the system to bypass these restrictions. This occurs because the resource manager does not properly validate or enforce the class-specific exclusion rules that should prevent unauthorized access to USB devices based on their classification within the USB device hierarchy.
The operational impact of this vulnerability is significant for systems running affected SUSE Linux versions, as it allows local users to gain unauthorized access to USB devices that would normally be restricted based on their class identifiers. This creates a potential attack vector where malicious users could access sensitive USB peripherals, potentially leading to data exfiltration, device manipulation, or further system compromise. The vulnerability specifically affects USB devices that set their class ID at the interface level, which includes many common peripheral devices such as storage devices, communication devices, and specialized hardware that might contain sensitive data or system access points.
From a cybersecurity perspective, this vulnerability aligns with CWE-284, which addresses improper access control in software systems, and represents a clear violation of the principle of least privilege. The flaw demonstrates inadequate input validation and access control enforcement mechanisms within the Linux USB subsystem, creating a persistent security weakness that could be exploited by attackers with local system access. The ATT&CK framework categorizes this as a privilege escalation technique through system binary exploitation, as local users could leverage this weakness to gain elevated access to restricted USB resources. Organizations should implement immediate mitigations including updating to patched versions of SUSE Linux, implementing additional access controls, and monitoring for unauthorized USB device access patterns to prevent exploitation of this vulnerability.
The broader implications extend beyond simple access control bypass, as this vulnerability could enable attackers to escalate privileges through USB-based attack vectors or to gain access to sensitive data stored on restricted USB devices. System administrators should consider implementing additional security measures such as USB device whitelisting, enhanced monitoring of USB device connections, and regular security assessments to identify potential exploitation attempts. The vulnerability also highlights the importance of proper access control implementation in device management subsystems and serves as a reminder of the critical need for thorough validation of access control mechanisms in operating system components that manage hardware resources.