CVE-2018-18504 in Firefox
Summary
by MITRE
A crash and out-of-bounds read can occur when the buffer of a texture client is freed while it is still in use during graphic operations. This results is a potentially exploitable crash and the possibility of reading from the memory of the freed buffers. This vulnerability affects Firefox < 65.
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Analysis
by VulDB Data Team • 05/08/2020
This vulnerability represents a critical memory safety issue in the Firefox browser's graphics rendering subsystem where improper handling of texture client buffers leads to exploitable conditions. The flaw occurs when a buffer allocated for texture client operations is prematurely freed while still actively referenced during graphic processing operations, creating a classic use-after-free scenario that can be leveraged by attackers to execute arbitrary code. The vulnerability specifically affects Firefox versions prior to 65, indicating it was present in the browser's graphics handling mechanisms for an extended period. This type of vulnerability falls under the CWE-416 category of Use After Free, which is a well-documented and highly dangerous class of memory corruption vulnerabilities that have been extensively catalogued in the CWE database and frequently targeted in exploit development.
The technical exploitation of this vulnerability involves manipulating the graphics rendering pipeline to trigger the premature buffer deallocation while the graphics operations are still in progress. When the buffer is freed but the graphics system continues to reference it, the memory management subsystem may return the same memory region to other allocations, creating a scenario where reading from the freed buffer can expose sensitive data or allow for code execution through controlled memory corruption. The out-of-bounds read aspect of this vulnerability allows attackers to potentially access memory regions that should no longer be accessible, providing opportunities for information disclosure and privilege escalation. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, as the exploitation would likely occur through malicious web content that triggers the vulnerable graphics rendering path.
The operational impact of this vulnerability is severe as it provides attackers with a potential path to arbitrary code execution within the context of the Firefox browser. The crash condition combined with the memory read capabilities creates a multi-faceted attack vector that can be exploited through web-based attacks without requiring user interaction beyond visiting a malicious website. This vulnerability affects the browser's core graphics rendering functionality, which is extensively used in modern web applications that rely heavily on canvas operations, WebGL rendering, and other graphics-intensive features. The vulnerability's presence in Firefox versions prior to 65 means that a significant portion of the browser user base would have been exposed to this risk, particularly since WebGL and canvas operations are commonly used across the web. The exploitation of this vulnerability can lead to complete browser compromise, potential system access, and the ability to execute malicious code with the privileges of the browser process, making it a critical security concern for any organization relying on Firefox for web browsing operations.