CVE-2016-5277 in Firefox
Summary
by MITRE
Use-after-free vulnerability in the nsRefreshDriver::Tick function in Mozilla Firefox before 49.0 and Firefox ESR 45.x before 45.4 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) by leveraging improper interaction between timeline destruction and the Web Animations model implementation.
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Analysis
by VulDB Data Team • 09/20/2022
The vulnerability CVE-2016-5277 represents a critical use-after-free condition affecting Mozilla Firefox versions prior to 49.0 and Firefox ESR 45.x versions prior to 45.4. This flaw resides within the nsRefreshDriver::Tick function which is responsible for managing animation timelines and refresh rates in the browser's rendering engine. The issue emerges from improper synchronization between timeline destruction processes and the Web Animations model implementation, creating a scenario where freed memory locations can be accessed and manipulated by malicious actors. The vulnerability is classified under CWE-416 as a use-after-free condition, which occurs when a program continues to reference memory after it has been freed, leading to unpredictable behavior and potential exploitation. The flaw specifically impacts the browser's handling of web animations and timeline management, where the destruction of animation timelines does not properly synchronize with ongoing animation processing, resulting in dangling pointers that can be exploited.
The operational impact of this vulnerability extends beyond simple denial of service to encompass full remote code execution capabilities. Attackers can leverage this use-after-free condition to corrupt heap memory and potentially execute arbitrary code with the privileges of the victim user. The heap corruption occurs when the nsRefreshDriver::Tick function attempts to access animation timeline objects that have already been destroyed, creating a scenario where memory layout can be manipulated to achieve code execution. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1070.004 for indicator removal on host, as exploitation may involve crafting malicious web content that triggers the vulnerable code path. The attack vector requires a user to visit a malicious website that contains specially crafted web animations, making this a prevalent threat in phishing campaigns and drive-by download scenarios where attackers can leverage the browser's animation processing to gain unauthorized access to systems.
Mitigation strategies for CVE-2016-5277 primarily focus on immediate version updates to Firefox 49.0 or Firefox ESR 45.4 and later releases where the vulnerability has been patched. The fix addresses the synchronization issue between timeline destruction and animation processing by ensuring proper reference counting and object lifecycle management within the nsRefreshDriver component. Organizations should implement comprehensive patch management policies to ensure all Firefox installations are updated promptly, particularly in enterprise environments where browser security is critical. Additional defensive measures include deploying web application firewalls that can detect and block malicious animation content, implementing browser security policies that restrict access to potentially harmful websites, and conducting regular security assessments to identify vulnerable systems. The vulnerability demonstrates the importance of proper memory management in browser engines and highlights the need for thorough testing of interaction between different components, particularly in complex systems where timing and synchronization issues can lead to severe security implications. Security teams should also monitor for related vulnerabilities in similar browser components and maintain awareness of the evolving threat landscape surrounding web-based exploits.