CVE-2004-2408 in Linux-Vserver
Summary
by MITRE
Linux VServer 1.27 and earlier, 1.3.9 and earlier, and 1.9.1 and earlier shares /proc permissions across all virtual and host servers, which allows local users with the ability to set permissions in /proc to obtain system information or cause a denial of service on other virtual servers or the host server.
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Analysis
by VulDB Data Team • 06/29/2018
The vulnerability identified as CVE-2004-2408 represents a critical security flaw in Linux VServer implementations affecting versions 1.27 and earlier, 1.3.9 and earlier, and 1.9.1 and earlier. This issue stems from improper permission handling within the virtualization framework where the /proc filesystem permissions are shared across all virtual servers and the host system. The fundamental problem lies in the lack of proper isolation mechanisms that should prevent virtual environments from accessing or manipulating the proc filesystem of other virtual environments or the underlying host system.
The technical flaw manifests when local users within a virtual server possess the capability to modify permissions within the /proc directory structure. This permission manipulation creates a pathway for information disclosure and denial of service attacks that can affect not only the compromised virtual environment but also other virtual servers and potentially the host system itself. The vulnerability essentially breaks the isolation boundaries that virtualization technologies are designed to maintain, allowing malicious actors to escalate their privileges and access sensitive system information. This flaw directly relates to CWE-276, which describes improper permissions for critical resources, and represents a classic case of inadequate access control within virtualized environments.
The operational impact of this vulnerability is significant and multifaceted. Attackers can leverage this flaw to gather sensitive system information that would normally be restricted to the host system or other virtual environments, potentially exposing kernel parameters, process information, and other critical data. Additionally, the ability to cause denial of service conditions across multiple virtual servers and the host system creates substantial operational risks for organizations relying on virtualization technologies. This vulnerability undermines the core security principles of virtualization by allowing lateral movement of malicious activities and information gathering that should be prevented by proper isolation mechanisms.
From an adversary perspective, this vulnerability aligns with ATT&CK technique T1059.001 for command and control through the /proc filesystem and T1068 for privilege escalation by exploiting weak access controls. Organizations using affected Linux VServer versions face increased risk of data breaches and system compromise, as attackers can use this vulnerability to establish persistent access across multiple virtual environments. The remediation approach requires immediate patching of the VServer implementation to address the permission handling issues and ensure proper isolation between virtual environments and the host system. System administrators should also implement additional monitoring and access control measures to detect potential exploitation attempts and maintain overall system integrity.
This vulnerability demonstrates the critical importance of proper isolation mechanisms in virtualized environments and highlights the need for comprehensive security testing of virtualization platforms. The flaw represents a fundamental design weakness in the permission model implementation that should have been addressed through proper access control and resource isolation protocols. Organizations should conduct thorough security assessments of their virtualization infrastructure and implement appropriate security controls to prevent similar vulnerabilities from being exploited in other virtualization technologies. The incident underscores the necessity of maintaining up-to-date virtualization software and implementing robust security monitoring to detect and respond to such cross-environment security issues effectively.