CVE-2016-3243 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 10 and 11 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site, aka "Internet Explorer Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 09/01/2022
The vulnerability identified as CVE-2016-3243 represents a critical memory corruption flaw affecting Microsoft Internet Explorer versions 10 and 11. This vulnerability resides within the browser's handling of memory management during web page rendering processes, creating an exploitable condition that can be triggered through maliciously crafted web content. The flaw stems from inadequate input validation and memory boundary checking mechanisms within the browser's JavaScript engine, specifically affecting how the browser processes certain object types and memory allocations. Security researchers have classified this issue as a heap-based buffer overflow, which occurs when the browser attempts to write data beyond the allocated memory boundaries, potentially leading to arbitrary code execution or system instability. The vulnerability is particularly concerning because it affects widely deployed browser versions that remain in use across numerous enterprise environments, making it a prime target for cybercriminals seeking persistent access to corporate networks.
The technical exploitation of this memory corruption vulnerability follows a well-established pattern within the realm of browser-based attacks, aligning with common attack vectors described in the attack technique framework. Attackers can craft malicious web pages containing specially designed JavaScript code that triggers the memory corruption when the browser attempts to render the page. The flaw typically manifests through the manipulation of object properties and memory addresses, leveraging the browser's memory management functions to overwrite critical memory locations. This type of vulnerability maps directly to CWE-121, heap-based buffer overflow, and CWE-125, out-of-bounds read, both of which are fundamental memory safety issues that have plagued software development for decades. The attack surface is broad as any web page loaded in Internet Explorer 10 or 11 could potentially serve as an attack vector, making this vulnerability particularly dangerous in phishing campaigns and drive-by download scenarios. The exploitation process often requires sophisticated techniques including information leakage and return-oriented programming to achieve reliable code execution on target systems.
The operational impact of CVE-2016-3243 extends far beyond simple denial of service conditions, as successful exploitation can result in complete system compromise and persistent access to target environments. When an attacker successfully exploits this vulnerability, they can execute arbitrary code with the privileges of the user running the browser, potentially leading to privilege escalation, data exfiltration, and establishment of backdoors. The memory corruption can cause the browser to crash and restart, but more critically, it can be leveraged to inject malicious payloads into the browser's memory space, enabling further attack progression. Organizations with legacy Internet Explorer installations face significant risk as this vulnerability has been actively exploited in the wild, particularly in targeted attacks against government and corporate entities. The vulnerability's persistence across multiple versions of Internet Explorer means that organizations cannot simply upgrade to newer browser versions to mitigate the risk, requiring immediate patch management or alternative security controls. Network security teams must implement monitoring for suspicious web traffic patterns and malicious content delivery that could indicate exploitation attempts.
Mitigation strategies for CVE-2016-3243 should encompass multiple layers of defense to protect against exploitation attempts. The most critical immediate action involves applying the relevant Microsoft security patches that address the memory corruption flaw in Internet Explorer 10 and 11. Organizations should also implement browser hardening measures including disabling unnecessary browser features, implementing strict content security policies, and utilizing sandboxing technologies to limit the potential impact of successful exploitation attempts. The implementation of web application firewalls and network-based intrusion detection systems can help detect and block malicious web content before it reaches vulnerable systems. Security teams should also consider implementing browser isolation techniques and transitioning to more secure browser alternatives that have better memory safety mechanisms and regular security updates. Regular security assessments and vulnerability scanning should be conducted to identify any remaining vulnerable installations and ensure comprehensive protection across all endpoints. The vulnerability's classification under ATT&CK technique T1203, Exploitation for Client Execution, emphasizes the need for layered defense approaches that address both the technical vulnerability and the broader attack lifecycle. Organizations should also maintain up-to-date threat intelligence feeds to monitor for new exploitation techniques targeting this specific vulnerability and ensure their defensive measures remain effective against evolving attack methods.