CVE-2016-7203 in Edge
Summary
by MITRE
The Chakra JavaScript scripting engine in Microsoft Edge allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site, aka "Scripting Engine Memory Corruption Vulnerability," a different vulnerability than CVE-2016-7200, CVE-2016-7201, CVE-2016-7202, CVE-2016-7208, CVE-2016-7240, CVE-2016-7242, and CVE-2016-7243.
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Analysis
by VulDB Data Team • 02/18/2025
The vulnerability identified as CVE-2016-7203 represents a critical memory corruption flaw within Microsoft Edge's Chakra JavaScript engine, which serves as the core component responsible for executing JavaScript code in the browser environment. This vulnerability specifically affects the scripting engine's handling of memory management during JavaScript execution, creating opportunities for remote attackers to manipulate memory structures in ways that can lead to arbitrary code execution or system instability. The issue is particularly concerning because it operates at the fundamental level of JavaScript interpretation, where malicious code can be embedded in legitimate web pages and executed without user interaction, making it a prime target for drive-by attack scenarios.
Technical analysis reveals that the memory corruption occurs when the Chakra engine processes certain JavaScript constructs or objects in ways that bypass normal memory allocation and deallocation procedures. The vulnerability stems from improper handling of object references and memory pointers during JavaScript execution, particularly when dealing with complex object hierarchies or dynamic property modifications. Attackers can craft malicious web pages that, when loaded in Microsoft Edge, trigger specific code paths within the Chakra engine that result in memory corruption. This corruption can manifest as buffer overflows, use-after-free conditions, or other memory management errors that allow attackers to overwrite critical memory regions with malicious code or cause the browser to crash through denial of service conditions.
The operational impact of CVE-2016-7203 extends beyond simple exploitation capabilities, as it represents a fundamental weakness in the browser's security architecture that can be leveraged across multiple attack vectors. The vulnerability's classification under CWE-125 indicates it involves out-of-bounds read conditions, while its relationship to memory corruption patterns aligns with ATT&CK technique T1059.1001 for JavaScript execution. Organizations running Microsoft Edge browsers are particularly vulnerable since the exploit requires no user interaction beyond visiting a malicious website, making it an ideal candidate for automated attack campaigns. The vulnerability's similarity to other related CVEs in the same advisory cycle suggests a broader pattern of memory management issues within the Chakra engine, indicating potential for additional related vulnerabilities to be discovered.
Mitigation strategies for CVE-2016-7203 primarily focus on immediate patch deployment through Microsoft's security updates, as the vulnerability requires no user interaction for exploitation. System administrators should prioritize updating Microsoft Edge to versions that include the patched Chakra engine, with particular attention to the specific cumulative update releases that address this memory corruption issue. Network security controls can include implementing web filtering solutions that block access to known malicious domains and monitoring for suspicious JavaScript behavior patterns. Additionally, browser hardening measures such as enabling sandboxing features, disabling unnecessary JavaScript capabilities, and implementing content security policies can provide additional layers of protection. The vulnerability's nature as a memory corruption issue also makes it suitable for exploit mitigation through Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP) mechanisms, though these protections are most effective when combined with proper patch management and system hardening practices.