CVE-2016-7243 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-2016-7203, CVE-2016-7208, CVE-2016-7240, and CVE-2016-7242.
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Analysis
by VulDB Data Team • 09/29/2022
The CVE-2016-7243 vulnerability represents a critical memory corruption flaw within Microsoft Edge's Chakra JavaScript engine that enables remote code execution or denial of service attacks through malicious web content. This vulnerability specifically targets the scripting engine's handling of JavaScript objects and memory management, creating a pathway for attackers to manipulate memory structures in ways that can lead to arbitrary code execution. The flaw operates by exploiting improper memory handling during JavaScript object operations, allowing malicious actors to craft web pages that trigger buffer overflows or use-after-free conditions within the Chakra engine's memory management subsystem. The vulnerability is particularly dangerous because it operates at the core of Edge's JavaScript processing capabilities, making it accessible through standard web browsing activities without requiring any special privileges or user interaction beyond visiting a compromised website.
The technical implementation of this vulnerability involves specific memory corruption patterns that occur when the Chakra engine processes certain JavaScript constructs. Attackers can leverage this flaw by creating web pages containing malicious JavaScript code that triggers improper memory allocation or deallocation sequences, leading to memory corruption that can be exploited to execute arbitrary code with the privileges of the Edge process. The vulnerability's classification as a memory corruption issue aligns with CWE-122, which covers heap-based buffer overflow conditions, and CWE-125, which addresses out-of-bounds read errors. The attack vector typically involves crafting JavaScript code that manipulates object references in ways that cause the engine to write beyond allocated memory boundaries or access freed memory locations, creating opportunities for code injection and privilege escalation.
From an operational impact perspective, this vulnerability represents a significant threat to enterprise security environments where Microsoft Edge serves as the primary browser for web-based applications and internet access. The remote exploitation capability means that attackers can compromise systems simply by having users visit malicious websites, making it particularly dangerous in phishing campaigns or compromised web hosting scenarios. The vulnerability affects all versions of Microsoft Edge that incorporate the Chakra JavaScript engine, creating a broad attack surface across various Windows operating systems. Organizations may experience unauthorized access to sensitive data, system compromise, and potential lateral movement within network environments. The vulnerability's similarity to other Chakra-related issues like CVE-2016-7200 through CVE-2016-7242 demonstrates a pattern of memory management flaws within the engine, indicating potential systematic weaknesses in the JavaScript engine's memory safety mechanisms.
Mitigation strategies for CVE-2016-7243 should focus on immediate patch deployment through Microsoft's security updates, as well as implementing additional security controls to reduce attack surface. Organizations should consider implementing browser isolation techniques, network-based protections, and monitoring for suspicious JavaScript execution patterns. The vulnerability's exploitation requires specific conditions related to JavaScript object handling, making it potentially detectable through behavioral analysis and intrusion detection systems. Security teams should also consider implementing web application firewalls and content filtering solutions to prevent access to known malicious domains. Additionally, user education regarding safe browsing practices and awareness of social engineering tactics that might lead to visiting compromised websites remains crucial. The ATT&CK framework categorizes this vulnerability under T1059.007 for JavaScript execution and T1203 for exploitation of web applications, highlighting the need for comprehensive defensive measures that address both endpoint protection and network-based security controls. Organizations should also consider implementing zero-trust network architectures that minimize the impact of potential compromises through strict access controls and continuous monitoring of system activities.