CVE-2016-2836 in Firefox
Summary
by MITRE
Multiple unspecified vulnerabilities in the browser engine in Mozilla Firefox before 48.0 and Firefox ESR 45.x before 45.3 allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via vectors related to Http2Session::Shutdown and SpdySession31::Shutdown, and other vectors.
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Analysis
by VulDB Data Team • 10/23/2024
The vulnerability identified as CVE-2016-2836 represents a critical security flaw affecting Mozilla Firefox versions prior to 48.0 and Firefox ESR 45.x versions before 45.3. This issue resides within the browser engine's handling of HTTP/2 and SPDY protocol sessions, specifically during the shutdown processes of these connection management components. The vulnerability stems from improper memory management and handling of session termination procedures, creating exploitable conditions that can be leveraged by remote attackers to compromise system integrity.
The technical exploitation of this vulnerability occurs through manipulation of Http2Session::Shutdown and SpdySession31::Shutdown functions within Firefox's networking stack. These functions are responsible for properly terminating HTTP/2 and SPDY protocol connections when they are no longer needed. When these shutdown procedures encounter malformed or maliciously crafted input data, they fail to properly release allocated memory resources or validate the state of connection objects, leading to memory corruption conditions. The flaw manifests as heap-based buffer overflows or use-after-free conditions that can result in application crashes or potentially enable arbitrary code execution.
From an operational impact perspective, this vulnerability creates significant risk for users of affected Firefox versions. Remote attackers can exploit these flaws to either cause denial of service attacks that crash the browser application, effectively preventing legitimate users from accessing web content, or potentially gain remote code execution capabilities. The memory corruption issues can be particularly dangerous as they may allow attackers to execute malicious code with the privileges of the browser process, potentially leading to full system compromise. The vulnerability affects both regular Firefox releases and Extended Support Release versions, indicating the widespread nature of the flaw across different Firefox deployment scenarios.
The attack vectors for this vulnerability are primarily remote and can be triggered through malicious web content or specially crafted network responses. Attackers typically need to craft web pages or server responses that force Firefox to establish and subsequently terminate HTTP/2 or SPDY connections in ways that trigger the vulnerable code paths. This makes the vulnerability particularly dangerous in web browsing contexts where users may unknowingly encounter malicious content. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write conditions, both of which are common manifestations of memory corruption vulnerabilities in network protocol implementations.
Organizations and users should immediately upgrade to Firefox version 48.0 or later, or Firefox ESR 45.3 or later, to mitigate this vulnerability. Additionally, implementing network monitoring solutions that can detect unusual HTTP/2 and SPDY traffic patterns may help identify potential exploitation attempts. Security teams should also consider deploying web application firewalls and content filtering solutions that can block suspicious protocol handling behaviors. The remediation process should include comprehensive testing of browser upgrades in controlled environments before full deployment to ensure compatibility with existing web applications and services. This vulnerability demonstrates the critical importance of maintaining current browser versions and implementing robust patch management processes to protect against known security flaws in widely used software components.