CVE-2011-2601 in Mac OS X
Summary
by MITRE
The GPU support functionality in Mac OS X does not properly restrict rendering time, which allows remote attackers to cause a denial of service (desktop hang) via vectors involving WebGL and (1) shader programs or (2) complex 3D geometry, as demonstrated by using Mozilla Firefox or Google Chrome to visit the lots-of-polys-example.html test page in the Khronos WebGL SDK.
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Analysis
by VulDB Data Team • 01/26/2018
The vulnerability identified as CVE-2011-2601 represents a critical flaw in the graphics processing unit support functionality of Mac OS X operating systems. This issue specifically affects the way the system handles graphics rendering operations, particularly those involving WebGL technology which is used to render 3D graphics in web browsers without requiring additional plugins or extensions. The flaw exists within the GPU acceleration mechanisms that are designed to offload graphics processing from the CPU to the dedicated graphics hardware, thereby improving performance and user experience.
The technical root cause of this vulnerability lies in the improper restriction of rendering time within the graphics processing subsystem. When web browsers such as Firefox or Chrome execute WebGL content, they communicate with the underlying operating system's graphics framework to perform complex rendering operations. The flaw occurs when these operations are not properly bounded or limited in execution time, allowing malicious or specially crafted web content to consume excessive GPU resources. This can happen through two primary vectors: the execution of complex shader programs that require significant computational resources, or through the rendering of highly detailed 3D geometric models that overwhelm the graphics processing capabilities.
The operational impact of this vulnerability is severe as it enables remote attackers to execute a denial of service attack against Mac OS X systems. When exploited, the vulnerability causes the desktop environment to become unresponsive or completely hang, effectively rendering the system unusable to the end user. This occurs because the GPU becomes overwhelmed with rendering tasks that exceed normal processing capabilities, causing the entire desktop interface to freeze. The attack can be initiated remotely through web browsers when users visit malicious websites or view specially crafted web content that triggers the vulnerable rendering paths. The demonstration using the Khronos WebGL SDK's lots-of-polys-example.html test page illustrates how easily this vulnerability can be exploited, as it contains the specific type of complex 3D geometry that triggers the resource exhaustion condition.
This vulnerability aligns with CWE-775, which addresses the improper handling of resource consumption, and relates to the broader category of denial of service attacks that target system resources. From an ATT&CK framework perspective, this represents a technique for maintaining access and availability by exploiting system resources, specifically targeting the graphics subsystem to cause system instability. The vulnerability demonstrates how modern operating systems' reliance on hardware acceleration for performance can create new attack surfaces when proper resource management and time limiting mechanisms are not implemented. The attack vector specifically targets the WebGL rendering pipeline, which is part of the broader category of web-based exploits that leverage browser capabilities to compromise system stability. Organizations should consider this vulnerability as part of their broader security posture assessment, particularly in environments where users frequently access untrusted web content, as the impact extends beyond simple service disruption to potentially affecting user productivity and system availability.