CVE-2017-5379 in Firefox
Summary
by MITRE
Use-after-free vulnerability in Web Animations when interacting with cycle collection found through fuzzing. This vulnerability affects Firefox < 51.
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Analysis
by VulDB Data Team • 08/02/2020
The vulnerability identified as CVE-2017-5379 represents a critical use-after-free flaw within Firefox's Web Animations implementation that emerged through fuzzing techniques. This issue specifically manifests during interactions with cycle collection mechanisms, creating a dangerous scenario where memory previously freed by the application becomes accessible for reuse. The vulnerability exists in Firefox versions prior to 51, making older installations particularly susceptible to exploitation. The root cause stems from improper memory management practices where objects are not adequately tracked during garbage collection cycles, leading to potential memory corruption scenarios that could be leveraged by malicious actors.
The technical nature of this vulnerability aligns with CWE-416, which describes the use of freed memory condition where a program continues to reference memory that has already been deallocated. In the context of web browsers, this flaw occurs when the cycle collection process fails to properly manage object references within the Web Animations API. When animation objects undergo garbage collection, references to these objects may persist in memory even after the underlying memory has been freed, creating opportunities for attackers to manipulate the freed memory regions. The fuzzing process that discovered this vulnerability indicates the flaw was exposed through randomized input testing that specifically targeted memory management functions within the browser's rendering engine.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides potential attack vectors for remote code execution. An attacker could craft malicious web content that triggers the specific sequence of events leading to the use-after-free condition, potentially allowing them to execute arbitrary code with the privileges of the browser process. This represents a significant security risk given that web browsers serve as primary attack surfaces for most users. The vulnerability's exploitation potential is further amplified by the fact that it occurs during normal web browsing operations, making it difficult to detect and prevent through standard security measures. Attackers could leverage this flaw to bypass modern security mitigations such as address space layout randomization and data execution prevention mechanisms.
Mitigation strategies for CVE-2017-5379 primarily focus on immediate version upgrades to Firefox 51 or later, which contain the necessary patches addressing the memory management issues within the Web Animations API. Organizations should implement comprehensive patch management procedures to ensure all browser installations are updated promptly, as this vulnerability represents a persistent risk for unpatched systems. Additional protective measures include enabling browser security features such as sandboxing and content security policies, while monitoring network traffic for suspicious activity that might indicate exploitation attempts. The vulnerability's classification under the ATT&CK framework would align with techniques involving memory corruption and privilege escalation, emphasizing the need for layered security approaches that include network monitoring, endpoint protection, and regular security assessments to detect and prevent exploitation attempts targeting such fundamental browser vulnerabilities.