CVE-2006-1376 in Linux
Summary
by MITRE
The installation of Debian GNU/Linux 3.1r1 from the network install CD creates /var/log/debian-installer/cdebconf with world writable permissions, which allows local users to cause a denial of service (disk consumption).
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Analysis
by VulDB Data Team • 07/21/2018
The vulnerability described in CVE-2006-1376 represents a critical security flaw in the Debian GNU/Linux 3.1r1 network installation process that stems from improper file permission handling during system setup. This issue manifests when the installation media creates the /var/log/debian-installer/cdebconf file with world-writable permissions, creating an exploitable condition that can be leveraged by local users to disrupt system operations. The flaw exists specifically within the installation framework's initialization sequence where temporary log files are created without adequate security controls, violating fundamental principles of least privilege and secure file handling.
The technical nature of this vulnerability aligns with CWE-732, which addresses inadequate permissions for critical system resources, and demonstrates how improper access control can lead to system instability. During the network installation process, the system creates a log file that should only be accessible to the installation process and authorized system components. However, the world-writable permissions allow any local user to write to this file, potentially consuming all available disk space through malicious file manipulation. This creates a classic denial of service scenario where an attacker can fill the disk partition with data, rendering the system unable to function properly and preventing legitimate system operations from completing.
The operational impact of this vulnerability extends beyond simple disk consumption, as it can effectively cripple the installation process and potentially compromise the entire system's stability. Local users with minimal privileges can exploit this condition to exhaust storage resources, causing the installation to fail or the system to become unresponsive. The vulnerability is particularly concerning because it occurs during the critical installation phase when the system is already in a vulnerable state, making it difficult to detect and remediate. This condition can be exploited to prevent legitimate system administration tasks from completing successfully, as the installation process requires adequate disk space to function properly.
Mitigation strategies for this vulnerability should focus on proper file permission management and access control implementation. System administrators should ensure that log files created during installation processes are properly secured with restrictive permissions, typically limiting access to the root user or specific system processes. The recommended approach involves setting appropriate file permissions such as 600 or 640, depending on the specific requirements of the installation process. Additionally, implementing proper file system monitoring and alerting mechanisms can help detect unusual disk space consumption patterns that may indicate exploitation attempts. This vulnerability highlights the importance of adhering to security best practices during system installation and emphasizes the need for comprehensive access control mechanisms throughout the entire system lifecycle. The issue also demonstrates how seemingly minor permission misconfigurations can lead to significant operational disruptions and should be addressed through proper security hardening procedures and regular system audits.