CVE-2016-5275 in Firefox
Summary
by MITRE
Buffer overflow in the mozilla::gfx::FilterSupport::ComputeSourceNeededRegions function in Mozilla Firefox before 49.0 allows remote attackers to execute arbitrary code by leveraging improper interaction between empty filters and CANVAS element rendering.
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Analysis
by VulDB Data Team • 09/20/2022
The vulnerability identified as CVE-2016-5275 represents a critical buffer overflow flaw within the graphics rendering subsystem of Mozilla Firefox versions prior to 49.0. This issue resides in the mozilla::gfx::FilterSupport::ComputeSourceNeededRegions function, which handles the computation of source regions required for filter operations within the graphics pipeline. The vulnerability specifically manifests when processing empty filters in conjunction with canvas element rendering, creating a dangerous condition that can be exploited by remote attackers to achieve arbitrary code execution on affected systems.
The technical implementation of this vulnerability stems from improper bounds checking within the graphics filter processing logic. When Firefox encounters a canvas element with empty filter properties, the ComputeSourceNeededRegions function fails to properly validate the memory allocation required for processing these filter operations. This flaw creates a scenario where attacker-controlled input can cause the function to write beyond the allocated buffer boundaries, leading to memory corruption that can be leveraged for code execution. The vulnerability is particularly dangerous because it operates within the browser's graphics rendering context, which is frequently accessed during normal web browsing activities, making exploitation relatively straightforward for remote attackers.
The operational impact of CVE-2016-5275 extends beyond simple code execution capabilities to encompass significant security implications for web browsing environments. Attackers can exploit this vulnerability by crafting malicious web pages containing specially constructed canvas elements with empty filter properties, which when rendered by the vulnerable Firefox version trigger the buffer overflow condition. This type of attack falls under the ATT&CK technique of exploitation for execution and aligns with CWE-121, which describes stack-based buffer overflow conditions. The vulnerability demonstrates the critical importance of proper memory management in graphics rendering libraries, as the flaw exists in the core graphics processing code that handles visual effects and transformations commonly used in modern web applications.
Mitigation strategies for this vulnerability require immediate patching of Firefox installations to version 49.0 or later, where the buffer overflow has been addressed through proper bounds checking and memory allocation validation. Organizations should implement comprehensive browser update policies to ensure all endpoints receive security patches promptly, as this vulnerability affects the core rendering engine that is fundamental to web browsing operations. Additionally, network security controls such as web application firewalls and content filtering solutions can provide additional layers of protection by monitoring for suspicious canvas element usage patterns. The fix implemented by Mozilla involved strengthening the input validation within the graphics filter processing pipeline and ensuring proper memory boundary checks are performed before any buffer operations are executed, addressing the root cause of the improper interaction between empty filters and canvas rendering that enabled the exploit.