CVE-2016-3291 in Edge
Summary
by MITRE
Microsoft Internet Explorer 11 and Microsoft Edge mishandle cross-origin requests, 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 • 09/16/2022
The vulnerability identified as CVE-2016-3291 represents a significant information disclosure flaw in Microsoft's web browsers, specifically affecting Internet Explorer 11 and Microsoft Edge. This vulnerability stems from improper handling of cross-origin requests within the browser's security model, creating a pathway for malicious actors to exploit the underlying architecture and extract sensitive data from other origins. The flaw exploits the fundamental principles of web security that govern how browsers enforce same-origin policies to prevent unauthorized data access between different domains and protocols.
The technical implementation of this vulnerability occurs when browsers process cross-origin requests without proper validation of the origin source, allowing malicious websites to craft specific requests that can bypass normal security boundaries. Attackers can leverage this weakness by hosting a malicious website that attempts to access resources or data from other origins that should normally be restricted. The vulnerability specifically affects how browsers handle certain HTTP requests and responses, particularly when dealing with cross-domain communication where the browser's security mechanisms fail to properly isolate resources between different origins. This improper handling creates a window where sensitive information can be inadvertently exposed to unauthorized parties.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially enable more sophisticated attacks such as cross-site request forgery, session hijacking, and data exfiltration. Attackers can construct malicious web pages that, when visited by users, can retrieve cookies, authentication tokens, or other sensitive data from other domains that the user has previously accessed. The vulnerability is particularly dangerous because it operates at the browser level where users typically have high-privilege access to sensitive applications and services. This creates a vector for attackers to gather credentials, personal information, and potentially access corporate networks or sensitive systems that users have legitimate access to through their browser sessions.
From a cybersecurity framework perspective, this vulnerability aligns with CWE-200, which describes "Information Exposure" and represents a classic case of insufficient access control. The flaw also maps to several ATT&CK techniques including T1566 for malicious code delivery and T1071 for application layer protocols, as attackers can exploit this vulnerability to deliver malicious content and extract information through web-based attacks. Organizations affected by this vulnerability should prioritize immediate patching of affected browsers and implement additional network-level controls such as web application firewalls and content filtering solutions to mitigate potential exploitation attempts.
Mitigation strategies for CVE-2016-3291 should include immediate deployment of Microsoft security updates and patches, followed by comprehensive browser hardening measures. Network administrators should implement strict content security policies and monitor for suspicious cross-origin requests that may indicate exploitation attempts. Organizations should also conduct security awareness training to help users recognize potentially malicious websites and avoid visiting untrusted domains that may attempt to exploit this vulnerability. Regular security assessments and vulnerability scanning should be performed to identify any remaining instances of the vulnerable browser versions within the organization's environment, ensuring that all endpoints are properly secured against this information disclosure threat.