CVE-2016-3329 in Edge
Summary
by MITRE
Microsoft Internet Explorer 9 through 11 and Edge allow remote attackers to determine the existence of files via a crafted webpage, aka "Internet Explorer Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 09/13/2022
This vulnerability affects Microsoft Internet Explorer versions 9 through 11 and Microsoft Edge browsers, representing a significant information disclosure flaw that enables remote attackers to determine the existence of files on a target system. The vulnerability stems from how these browsers handle file access requests within web pages, creating a side-channel attack vector that can be exploited to infer file system information. The flaw specifically manifests when Internet Explorer processes certain web content that attempts to access files through JavaScript or other browser mechanisms, allowing attackers to craft malicious webpages that reveal whether specific files exist on the local system. This type of vulnerability falls under the CWE-200 category of "Information Exposure" and aligns with ATT&CK technique T1083 for discovering files and directories, making it particularly dangerous for attackers seeking to map file systems or identify sensitive resources. The vulnerability operates by leveraging browser rendering behaviors that inadvertently expose file system metadata or access patterns, creating a covert channel through which attackers can determine file existence without direct access to the files themselves. This information disclosure can be particularly damaging when combined with other reconnaissance activities, as it allows attackers to build detailed profiles of target systems and identify potential attack vectors.
The technical exploitation of this vulnerability requires attackers to craft specific web content that triggers the browser's file access mechanisms in a way that reveals information about local file system state. When Internet Explorer processes such malicious content, it may exhibit different behaviors or error messages depending on whether target files exist, creating observable differences that an attacker can monitor and interpret. The flaw is particularly concerning because it operates at the browser level and can be exploited through standard web browsing activities without requiring special privileges or direct system access. Attackers can leverage this vulnerability to perform reconnaissance activities that would otherwise be difficult or impossible through conventional means, potentially identifying sensitive documents, configuration files, or other resources that might contain valuable information for further attacks. The vulnerability's impact extends beyond simple file existence detection, as it can reveal patterns and structures within file systems that help attackers understand system organization and potentially identify high-value targets for exploitation.
The operational impact of this vulnerability is substantial for organizations that rely on Microsoft browsers for web-based activities, as it creates a persistent threat vector that can be exploited by remote attackers. Even when users are browsing legitimate websites, they may inadvertently encounter malicious content that exploits this vulnerability, making it particularly dangerous for enterprise environments where users frequently access untrusted web content. The vulnerability can be exploited through various attack vectors including phishing emails, compromised websites, or malicious advertisements, making it difficult to defend against through traditional network security measures alone. Organizations may experience cascading effects from this vulnerability as attackers use the information gathered to plan more sophisticated attacks, potentially leading to data breaches, privilege escalation, or system compromise. The long-term implications include increased attack surface for organizations, as this vulnerability can be combined with other information disclosure issues to create more comprehensive reconnaissance capabilities that significantly reduce the security posture of affected systems.
Mitigation strategies for this vulnerability should focus on both immediate remediation and long-term security improvements to protect against exploitation. Microsoft released security updates for this vulnerability through regular security patches, and organizations should ensure all affected browsers are updated to the latest versions with the appropriate security fixes. Browser hardening measures including disabling unnecessary file access capabilities, implementing strict content security policies, and using sandboxing mechanisms can help reduce the attack surface for this vulnerability. Network-based protections such as web application firewalls and intrusion detection systems can be configured to detect and block known exploit patterns associated with this vulnerability. Additionally, user education and awareness programs should emphasize the importance of avoiding untrusted web content and recognizing potential phishing attempts that may contain malicious code designed to exploit this vulnerability. Organizations should also implement monitoring solutions that can detect unusual file access patterns or browser behavior that might indicate exploitation attempts, providing early warning capabilities for potential attacks. The vulnerability's classification as an information disclosure issue means that defensive measures should focus on preventing the leakage of system information while maintaining legitimate browser functionality, requiring careful balance between security and usability considerations.