CVE-2016-3273 in Edge
Summary
by MITRE
The XSS Filter in Microsoft Internet Explorer 9 through 11 and Microsoft Edge does not properly restrict JavaScript code, which allows remote attackers to obtain sensitive information via a crafted web site, aka "Microsoft Browser Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 09/01/2022
The vulnerability identified as CVE-2016-3273 represents a critical cross-site scripting (XSS) filter bypass in Microsoft Internet Explorer versions 9 through 11 and Microsoft Edge browsers. This flaw resides in the browser's security mechanisms designed to prevent malicious JavaScript code execution, specifically undermining the protection against information disclosure attacks. The vulnerability operates by allowing attackers to craft malicious web pages that can bypass the built-in XSS filtering capabilities, enabling unauthorized access to sensitive data within the browser environment.
The technical implementation of this vulnerability stems from improper validation and sanitization of JavaScript code within the browser's security framework. When users navigate to malicious websites, the browser's XSS filter fails to adequately restrict or neutralize potentially harmful script content, creating a pathway for attackers to execute code that can access and exfiltrate sensitive information. This represents a fundamental failure in the browser's security model, where the filtering mechanism designed to prevent XSS attacks becomes ineffective against specific patterns of malicious input. The vulnerability is particularly concerning because it affects multiple versions of Microsoft's browser ecosystem, including both legacy Internet Explorer versions and the newer Edge browser, indicating a widespread impact across different browser architectures.
The operational impact of CVE-2016-3273 extends beyond simple script execution to encompass significant information disclosure capabilities that can compromise user privacy and system security. Attackers can leverage this vulnerability to access cookies, session tokens, and other sensitive browser data that may contain authentication credentials or personal information. The vulnerability aligns with CWE-79 Cross-site Scripting, which specifically addresses the improper handling of user-supplied input that can result in malicious code execution. From an adversarial perspective, this flaw enables threat actors to conduct sophisticated phishing attacks, session hijacking operations, and data exfiltration campaigns that can affect both individual users and enterprise environments.
Mitigation strategies for this vulnerability require immediate patch deployment through Microsoft's security updates, as the flaw represents a persistent security weakness in the browser's core functionality. Organizations should implement comprehensive browser security policies that include regular update management, network-based filtering solutions, and user education programs to reduce exposure to malicious websites. The ATT&CK framework categorizes this vulnerability under T1566 Initial Access through malicious web content, emphasizing the need for network-level defenses and endpoint protection measures. Additionally, browser hardening techniques such as enabling enhanced security features, implementing content security policies, and utilizing security extensions can provide additional layers of protection against exploitation attempts. Given the vulnerability's impact on multiple browser versions, organizations must ensure comprehensive coverage across their entire user base and implement monitoring solutions to detect potential exploitation attempts.