CVE-2005-3179 in Linux
Summary
by MITRE
drm.c in Linux kernel 2.6.10 to 2.6.13 creates a debug file in sysfs with world-readable and world-writable permissions, which allows local users to enable DRM debugging and obtain sensitive information.
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Analysis
by VulDB Data Team • 06/29/2025
The vulnerability described in CVE-2005-3179 represents a critical security flaw in the Linux kernel's Direct Rendering Manager subsystem that affected versions 2.6.10 through 2.6.13. This issue stems from improper permission handling within the drm.c file where a debug file is created in the sysfs filesystem with overly permissive world-readable and world-writable permissions. The Direct Rendering Manager is a kernel subsystem responsible for managing graphics hardware acceleration and direct rendering contexts, making it a crucial component for graphics-intensive applications and desktop environments. When a debug file is created with universal read and write access, it fundamentally undermines the security model of the kernel's device management system.
The technical flaw manifests through the creation of a debug interface file in sysfs that lacks proper access controls. Sysfs is a virtual filesystem in Linux that exposes kernel data structures and device information to userspace, making it a common target for both legitimate debugging and malicious exploitation. In this case, the drm.c implementation fails to properly restrict access to the debug file, allowing any local user to both read sensitive kernel information and modify debugging parameters. This creates a privilege escalation vector where unprivileged users can potentially enable debugging features that might reveal kernel memory contents, device state information, or other sensitive data that should remain restricted to kernel-level operations. The vulnerability directly maps to CWE-732: Incorrect Permission Assignment for Critical Resource, which specifically addresses situations where critical system resources are assigned incorrect permissions.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attacks. Local users with access to the system can exploit this weakness to gather kernel-level information that might aid in further exploitation attempts, including kernel version information, memory layouts, and device-specific details. The ability to enable DRM debugging also means that attackers can potentially manipulate kernel behavior through debugging interfaces, potentially leading to denial of service conditions or even privilege escalation in certain configurations. This vulnerability particularly affects systems running graphics-intensive applications where DRM is actively utilized, and it represents a fundamental failure in the kernel's security model for managing debug interfaces. The exposure of debugging information could provide attackers with valuable insights for crafting targeted attacks against the graphics subsystem or exploiting other kernel vulnerabilities that might be present in the same codebase.
Mitigation strategies for CVE-2005-3179 focus primarily on immediate patching of affected kernel versions to ensure proper permission handling for debug files. System administrators should prioritize upgrading to kernel versions 2.6.14 or later where this vulnerability has been addressed through proper access control implementation. Additionally, security-conscious deployments should consider implementing sysfs access controls through mount options or filesystem-level restrictions to prevent unauthorized access to debug interfaces. The fix typically involves modifying the drm.c file to create debug files with appropriate permissions that restrict access to root or specific privileged users only. Organizations should also conduct regular security audits of their kernel configurations and debug interfaces to identify similar permission issues across other subsystems. This vulnerability demonstrates the importance of maintaining strict access controls for kernel debug interfaces and aligns with ATT&CK technique T1068: Exploitation for Privilege Escalation, where attackers leverage insecure system interfaces to gain elevated privileges. The incident underscores the necessity of proper security review processes for kernel subsystems, particularly those handling device management and hardware interfaces.