CVE-2004-0667 in Linux
Summary
by MITRE
Rule Set Based Access Control (RSBAC) 1.2.2 through 1.2.3 allows access to sys_creat, sys_open, and sys_mknod inside jails, which could allow local users to gain elevated privileges.
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Analysis
by VulDB Data Team • 06/19/2018
The vulnerability identified as CVE-2004-0667 resides within the Rule Set Based Access Control (RSBAC) framework version 1.2.2 through 1.2.3, representing a critical flaw in Linux kernel security mechanisms designed to enforce access control policies. This issue specifically affects systems implementing RSBAC as their primary security model, where the framework operates as a kernel module to provide fine-grained access control capabilities. The vulnerability manifests in the improper handling of system calls within jail environments, which are isolated execution spaces designed to contain processes and limit their access to system resources. The flaw allows local users to bypass intended security boundaries through the exploitation of specific system call interfaces.
The technical root cause of this vulnerability stems from insufficient validation of system call permissions within the jail environment context. When processes operate inside jails, they should be restricted from performing certain privileged operations such as sys_creat, sys_open, and sys_mknod which are typically protected by the kernel's security framework. However, the RSBAC implementation fails to properly enforce these restrictions, creating a privilege escalation vector. The system calls sys_creat, sys_open, and sys_mknod are particularly dangerous because they allow for file creation, file access, and device node creation respectively, all of which can be leveraged to establish persistent access or escalate privileges within the compromised environment. This vulnerability directly maps to CWE-284, which describes improper access control issues in software systems.
The operational impact of this vulnerability is significant for systems relying on RSBAC for security enforcement, particularly in multi-tenant environments or systems where process isolation is critical. Local users who can execute code within a jail environment can exploit this flaw to gain elevated privileges, effectively breaking out of their restricted environment and potentially compromising the entire system. The attack vector requires local access and execution within a jail context, but once successful, it can lead to complete system compromise. This vulnerability is particularly concerning in environments where RSBAC is used for containerization or virtualization purposes, as it undermines the fundamental security assumptions of process isolation.
Security practitioners should immediately implement mitigations including updating to RSBAC versions 1.2.4 or later where this vulnerability has been patched, or implementing additional security controls to monitor and restrict access to privileged system calls within jail environments. The vulnerability demonstrates the importance of proper privilege separation in kernel modules and highlights the need for comprehensive testing of security mechanisms under various execution contexts. Organizations should also consider implementing additional monitoring for suspicious system call patterns and ensure that all kernel modules are regularly updated to address known security issues. This vulnerability aligns with ATT&CK technique T1068, which covers privilege escalation through local exploitation, and emphasizes the critical nature of kernel-level access control mechanisms in maintaining system integrity. The flaw underscores the necessity of thorough security auditing of kernel modules and proper implementation of access control policies that maintain strict boundaries between different security contexts within operating systems.