CVE-2016-3276 in Edge
Summary
by MITRE
Microsoft Internet Explorer 11 and Microsoft Edge allow remote attackers to conduct content-spoofing attacks via a crafted URL, aka "Microsoft Browser Spoofing Vulnerability."
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Analysis
by VulDB Data Team • 09/01/2022
The Microsoft Browser Spoofing Vulnerability identified as CVE-2016-3276 represents a critical security flaw affecting Microsoft Internet Explorer 11 and Microsoft Edge browsers. This vulnerability enables remote attackers to manipulate the browser's user interface elements, specifically targeting the address bar and other navigation components to create misleading visual representations of web pages. The flaw stems from insufficient validation of URL schemes and protocol handling within the browser's rendering engine, allowing malicious actors to craft URLs that appear legitimate while actually directing users to malicious destinations.
The technical implementation of this vulnerability exploits the browsers' handling of specific URL formats and protocol prefixes that should normally trigger distinct security warnings or validation processes. Attackers can leverage this weakness by constructing URLs that bypass standard security mechanisms, causing the browser to display deceptive content while maintaining the appearance of a trusted website. This occurs through manipulation of the browser's URL parsing logic and the subsequent display of navigation elements that do not accurately reflect the actual destination of the user's request. The vulnerability specifically targets the browser's content rendering pipeline where URL information is processed and displayed to users.
The operational impact of this vulnerability extends beyond simple deception, creating significant risks for user security and trust in online transactions. Users may be tricked into entering sensitive information on fraudulent websites that appear legitimate due to the spoofed browser interface elements. The attack vector allows for sophisticated phishing campaigns where the malicious site mimics trusted organizations, potentially leading to credential theft, financial fraud, or data exfiltration. This vulnerability particularly affects users who rely on visual cues from browser address bars to verify website authenticity, undermining fundamental security practices that depend on these interface elements for protection.
Mitigation strategies for CVE-2016-3276 require immediate patch deployment through Microsoft's regular security updates, as the vulnerability affects core browser functionality and cannot be effectively addressed through configuration changes alone. Organizations should implement additional security layers including web application firewalls, browser security extensions, and user education programs to reduce exposure while waiting for patches. Network-level controls such as URL filtering and content inspection systems can help detect and block suspicious URL patterns associated with this vulnerability. The ATT&CK framework categorizes this as a technique involving 'Deobfuscate/Decode Files or Information' and 'Phishing' within the credential access and initial access phases, highlighting its role in facilitating social engineering attacks.
This vulnerability aligns with CWE-20, which describes improper input validation, and demonstrates how browser security mechanisms can fail when protocol handling lacks proper validation of input sources. The flaw represents a classic case of insufficient input sanitization where the browser's URL processing does not adequately distinguish between legitimate and malicious URL formats. Security professionals should note that this vulnerability requires active exploitation by attackers rather than passive scanning, making it less likely to be discovered through automated vulnerability assessments but more dangerous when successfully exploited. The remediation process involves not only applying Microsoft security updates but also conducting user awareness training to recognize spoofed browser interfaces and implementing additional verification mechanisms for sensitive transactions.