CVE-2017-8735 in Edge
Summary
by MITRE
Microsoft Edge in Microsoft Windows 10 Gold, 1511, 1607, 1703, and Windows Server 2016 allows an attacker to trick a user by redirecting the user to a specially crafted website, due to the way that Microsoft Edge parses HTTP content, aka "Microsoft Edge Spoofing Vulnerability". This CVE ID is unique from CVE-2017-8724.
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Analysis
by VulDB Data Team • 01/12/2021
The vulnerability identified as CVE-2017-8735 represents a critical spoofing flaw within Microsoft Edge browser that affects multiple Windows 10 versions including Gold, 1511, 1607, and 1703, as well as Windows Server 2016. This security weakness stems from how Microsoft Edge handles HTTP content parsing, creating an avenue for attackers to manipulate user perception through deceptive web navigation. The vulnerability operates by exploiting the browser's handling of specific HTTP headers and content types, allowing malicious actors to craft websites that appear legitimate while actually redirecting users to harmful destinations. The flaw specifically targets the browser's user interface rendering and navigation behavior, making it particularly dangerous as users may not realize they have been redirected to malicious sites until it's too late.
The technical implementation of this vulnerability involves Microsoft Edge's failure to properly validate or sanitize HTTP content during the parsing process, creating a condition where attackers can manipulate the browser's visual representation of web pages. This allows for the creation of deceptive user interfaces that display false information about the actual website being visited, enabling phishing attacks and social engineering campaigns to succeed more effectively. The parsing inconsistency occurs when the browser encounters specific combinations of HTTP headers that should trigger different rendering behaviors, but instead fall into a parsing gap where the content manipulation remains undetected by the browser's security mechanisms.
From an operational perspective, this vulnerability poses significant risks to enterprise environments where users may inadvertently access malicious sites through social engineering tactics such as email attachments, compromised websites, or malicious links in communication channels. The impact extends beyond individual user compromise to potential corporate data breaches, credential theft, and lateral movement within network environments. Attackers can leverage this vulnerability to create convincing phishing pages that mimic legitimate banking, social media, or corporate portals, making user education and technical controls both essential for protection. The vulnerability's persistence across multiple Windows 10 releases indicates a fundamental flaw in the browser's architecture that required patching across several version lines.
Organizations should implement immediate mitigations including deploying Microsoft security updates, configuring browser security policies to restrict potentially dangerous content types, and implementing network-level controls to monitor and block suspicious HTTP content. The vulnerability aligns with CWE-1004 which addresses insecure default settings and CWE-20 which covers improper input validation, both of which are fundamental security principles violated in this case. From an ATT&CK framework perspective, this vulnerability maps to techniques such as T1566 for phishing and T1071 for application layer protocol usage, demonstrating how browser vulnerabilities can enable broader attack chains. Security teams should also consider implementing user awareness training to recognize potential spoofing attempts and establish monitoring procedures for detecting unusual browser behavior or unexpected redirects that may indicate exploitation attempts.