CVE-2016-2808 in Firefox
Summary
by MITRE
The watch implementation in the JavaScript engine in Mozilla Firefox before 46.0, Firefox ESR 38.x before 38.8, and Firefox ESR 45.x before 45.1 allows remote attackers to execute arbitrary code or cause a denial of service (generation-count overflow, out-of-bounds HashMap write access, and application crash) via a crafted web site.
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Analysis
by VulDB Data Team • 07/27/2022
The vulnerability identified as CVE-2016-2808 represents a critical flaw in Mozilla Firefox's JavaScript engine implementation that affects multiple versions of the browser. This issue resides within the watch mechanism, which is a legacy feature designed to monitor property access and modifications on objects. The vulnerability manifests in several distinct ways that can be exploited by remote attackers to gain unauthorized code execution capabilities or cause system instability through denial of service conditions. The affected versions include Firefox 46.0 and earlier, Firefox ESR 38.x versions prior to 38.8, and Firefox ESR 45.x versions before 45.1, indicating this flaw has been present for an extended period across multiple release channels.
The technical exploitation of this vulnerability involves sophisticated manipulation of the JavaScript engine's internal memory management systems. Attackers can craft malicious web pages that trigger specific conditions leading to generation-count overflow, which represents a fundamental flaw in how the engine tracks object lifecycle management. Additionally, the vulnerability enables out-of-bounds HashMap write access, indicating improper bounds checking within the engine's internal data structures. These memory corruption issues directly translate to potential arbitrary code execution capabilities when the JavaScript engine attempts to process malformed input through the watch implementation. The combination of these memory access violations creates a multi-vector attack surface that can be leveraged to compromise system integrity.
The operational impact of CVE-2016-2808 extends beyond simple denial of service conditions to represent a significant threat to user security and system stability. When successfully exploited, this vulnerability can allow remote attackers to execute arbitrary code with the privileges of the affected browser user, potentially leading to complete system compromise. The out-of-bounds memory access patterns create opportunities for attackers to manipulate the JavaScript engine's memory layout, potentially enabling privilege escalation or data theft. Furthermore, the application crash conditions can be used as a vector for persistent denial of service attacks against targeted users or systems, making this vulnerability particularly dangerous in enterprise environments where browser stability is critical for business operations.
Mitigation strategies for CVE-2016-2808 primarily focus on immediate version upgrades to patched releases of Mozilla Firefox. Organizations should prioritize updating all affected browser installations to versions 46.0 or later for regular releases, and to Firefox ESR 38.8 or 45.1 for extended support releases. Security administrators should also implement network-level protections such as content filtering and web application firewalls to block access to known malicious domains. Additionally, browser hardening measures including disabling unnecessary JavaScript features, implementing strict content security policies, and using sandboxing mechanisms can reduce the attack surface. This vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and maps to ATT&CK technique T1059.007 for JavaScript-based execution, emphasizing the need for comprehensive security measures that address both the immediate vulnerability and broader exploitation patterns.