CVE-2017-0221 in Edge
Summary
by MITRE
A vulnerability exists when Microsoft Edge improperly accesses objects in memory, aka "Microsoft Edge Memory Corruption Vulnerability." This CVE ID is unique from CVE-2017-0227 and CVE-2017-0240.
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Analysis
by VulDB Data Team • 09/24/2020
The vulnerability identified as CVE-2017-0221 represents a critical memory corruption flaw within Microsoft Edge browser that stems from improper object handling in memory management. This issue specifically affects the browser's rendering engine and occurs when Edge attempts to access objects that have already been freed or improperly allocated in memory. The vulnerability falls under the broader category of memory safety issues that have long plagued web browsers, where improper memory management can lead to arbitrary code execution. According to the Common Weakness Enumeration framework, this vulnerability maps to CWE-125: "Out-of-bounds Read" and CWE-787: "Out-of-bounds Write," both of which are fundamental memory safety weaknesses that enable attackers to manipulate memory contents. The flaw manifests when Edge's JavaScript engine processes certain web content that triggers improper memory access patterns, creating opportunities for attackers to execute malicious code with the privileges of the browser process.
The operational impact of CVE-2017-0221 extends beyond simple browser instability, as it provides attackers with a potential pathway for remote code execution on vulnerable systems. When exploited, this vulnerability allows adversaries to bypass modern security mitigations such as address space layout randomization and data execution prevention, particularly when users visit malicious websites or are tricked into opening specially crafted web content. The vulnerability's exploitation typically involves crafting specific JavaScript code or HTML content that triggers the memory corruption condition, which can then be leveraged to execute arbitrary commands on the target system. This aligns with tactics described in the MITRE ATT&CK framework under T1203: "Exploitation for Client Execution" and T1059: "Command and Scripting Interpreter," where attackers leverage browser vulnerabilities to establish persistent access or escalate privileges. The attack surface is particularly concerning given Edge's widespread use and the browser's integration with Windows operating systems, making successful exploitation potentially impactful across numerous enterprise and consumer environments.
Mitigation strategies for CVE-2017-0221 must address both immediate remediation and long-term security posture improvements. Microsoft released security updates that fixed the memory corruption issue by implementing proper object lifecycle management and adding additional validation checks in the browser's memory handling code. Organizations should prioritize applying the relevant security patches immediately, as the vulnerability was actively exploited in the wild prior to patch availability. Network defenders should consider implementing browser isolation techniques and web application firewalls to limit exposure to malicious web content, while also monitoring for indicators of compromise related to browser exploitation attempts. The vulnerability highlights the importance of regular security updates and the need for organizations to maintain robust patch management processes, particularly for widely used applications like web browsers. Additionally, user education regarding safe browsing practices and the avoidance of untrusted websites remains crucial, as many exploitation scenarios rely on social engineering to deliver malicious payloads that trigger the memory corruption vulnerability.