CVE-2004-1056 in Linux
Summary
by MITRE
Direct Rendering Manager (DRM) driver in Linux kernel 2.6 does not properly check the DMA lock, which could allow remote attackers or local users to cause a denial of service (X Server crash) and possibly modify the video output.
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Analysis
by VulDB Data Team • 03/10/2021
The vulnerability identified as CVE-2004-1056 resides within the Direct Rendering Manager driver component of the Linux kernel version 2.6, representing a critical security flaw that impacts graphics processing capabilities. This issue specifically affects the DRM subsystem which manages direct hardware access for graphics rendering operations, particularly in multi-user environments where X Server processes handle graphical user interfaces. The vulnerability stems from insufficient validation mechanisms within the DMA locking mechanism that governs data transfer operations between system memory and graphics hardware, creating potential attack vectors that can compromise system stability and graphical output integrity.
The technical flaw manifests through improper validation of the DMA lock mechanism, which serves as a critical synchronization point for managing concurrent access to graphics hardware resources. When the DRM driver fails to properly verify DMA lock states, malicious actors can exploit this weakness to manipulate the graphics subsystem in ways that lead to system instability. This improper lock checking allows unauthorized processes to interfere with ongoing graphics operations, potentially causing the X Server to crash due to corrupted memory states or invalid hardware commands. The vulnerability extends beyond simple denial of service to potentially enable modification of video output, as attackers can manipulate graphics rendering parameters through the compromised lock mechanism, affecting visual display integrity.
Operational impact of this vulnerability spans both local and remote attack scenarios, making it particularly dangerous for systems running graphical environments. Local users with access to the system can leverage this flaw to crash X Server processes, effectively rendering graphical interfaces unusable and forcing system administrators to restart critical services. Remote attackers can exploit similar pathways to cause denial of service conditions across networked systems, particularly affecting servers that rely on graphical processing capabilities or display services. The potential modification of video output represents an additional concern as it could enable sophisticated attacks where malicious actors manipulate visual content, potentially leading to information disclosure or further exploitation through visual-based attacks that rely on compromised graphics rendering.
Mitigation strategies for CVE-2004-1056 should focus on immediate kernel updates to patched versions that properly implement DMA lock validation mechanisms. System administrators must ensure that all Linux systems running kernel 2.6 are updated with security patches that address the DRM driver vulnerability, as the flaw remains exploitable in unpatched environments. Additional protective measures include implementing proper access controls and privilege separation for graphics subsystem processes, monitoring for anomalous X Server behavior, and applying network segmentation to limit exposure of graphical services to untrusted networks. The vulnerability aligns with CWE-129 which addresses improper validation of input boundaries, and relates to ATT&CK technique T1059 for execution through system services and T1499 for disruption of services through denial of service attacks. Organizations should also consider implementing intrusion detection systems that monitor for suspicious graphics driver activity and maintain comprehensive backup procedures to quickly restore services following potential exploitation attempts.