CVE-2017-8503 in Edge
Summary
by MITRE
Microsoft Edge in Microsoft Windows 10 1511, 1607, 1703, and Windows Server 2016 allows an attacker to escape from the AppContainer sandbox, aka "Microsoft Edge Elevation of Privilege Vulnerability". This CVE ID is unique from CVE-2017-8642.
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Analysis
by VulDB Data Team • 01/07/2021
The vulnerability identified as CVE-2017-8503 represents a critical elevation of privilege flaw in Microsoft Edge browser when running on specific Windows 10 versions and Windows Server 2016. This security weakness allows attackers to break out of the AppContainer sandbox protection mechanism that is designed to isolate applications and prevent them from accessing system resources without proper authorization. The vulnerability specifically affects Windows 10 versions 1511, 1607, and 1703, as well as Windows Server 2016, making it a widespread concern across multiple Microsoft operating system releases. The flaw enables malicious actors to escalate their privileges and gain unauthorized access to system-level resources that should normally be restricted to the browser application.
The technical root cause of this vulnerability lies in how Microsoft Edge handles certain memory operations and object management within the browser's rendering engine. Attackers can exploit this weakness by crafting malicious web content that triggers an improper memory access pattern, allowing them to manipulate the browser's execution context and bypass the sandbox isolation. This type of vulnerability falls under CWE-264, which describes permissions, privileges, and access control issues, specifically focusing on inadequate sandboxing mechanisms. The exploitation technique leverages the browser's interaction with the operating system's security model, where the AppContainer protection fails to properly enforce the boundaries between the browser process and system resources.
The operational impact of CVE-2017-8503 is severe and multifaceted, as it provides attackers with the capability to execute arbitrary code with elevated privileges on affected systems. Once successfully exploited, the vulnerability allows threat actors to perform actions such as installing malicious software, modifying system files, accessing sensitive data, and potentially establishing persistent backdoors. The attack surface is particularly concerning because Microsoft Edge is a widely used browser that users interact with regularly, making the exploitation vector highly accessible. This vulnerability directly maps to ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation', and also relates to T1059 for command and scripting interpreter usage that would follow privilege escalation. The risk is compounded by the fact that users may not immediately recognize when they have visited compromised websites, making this a stealthy and dangerous vulnerability.
Mitigation strategies for CVE-2017-8503 primarily focus on applying Microsoft's security patches and updates as soon as they become available. Organizations should prioritize updating their Windows 10 systems to versions that contain the fix for this vulnerability, particularly ensuring that all systems are running the latest cumulative updates. Additionally, implementing network-based protections such as web application firewalls and content filtering solutions can help reduce the risk of exploitation. Security administrators should also consider implementing additional monitoring controls to detect anomalous behavior that might indicate exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date security patches and demonstrates the critical need for organizations to have robust patch management processes in place to protect against known vulnerabilities in widely used software applications.