CVE-2016-3245 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 9 through 11 allows remote attackers to trick users into making TCP connections to a restricted port via a crafted web site, aka "Internet Explorer Security Feature Bypass Vulnerability."
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 09/01/2022
The vulnerability identified as CVE-2016-3245 represents a critical security flaw in Microsoft Internet Explorer versions 9 through 11 that enables remote attackers to bypass security restrictions through malicious web content. This issue specifically targets the browser's handling of TCP connections and demonstrates a significant weakness in the security model that governs network access permissions within the browser environment. The vulnerability operates by exploiting the way Internet Explorer processes web content that attempts to establish network connections to restricted ports, effectively allowing attackers to circumvent the normal security boundaries that should prevent such access.
The technical implementation of this vulnerability involves a sophisticated manipulation of Internet Explorer's security features, particularly those related to cross-domain restrictions and network access controls. Attackers can craft specifically designed web pages that exploit the browser's handling of TCP connection requests to ports that are typically restricted or blocked by security policies. This occurs through the manipulation of how the browser interprets and processes network connection attempts, allowing malicious actors to establish connections that should normally be prohibited. The flaw essentially creates a pathway for attackers to bypass the normal security boundaries that protect users from unauthorized network access, particularly when dealing with restricted port communications.
The operational impact of this vulnerability extends beyond simple network access bypass, as it represents a fundamental breakdown in the browser's security architecture that can enable further exploitation. Users who visit malicious websites containing crafted content can unknowingly establish TCP connections to restricted ports, potentially allowing attackers to access internal network resources or services that should remain protected. This vulnerability particularly affects enterprise environments where internal network services may be accessible through restricted ports, creating potential pathways for attackers to move laterally within networks or access sensitive internal systems. The security feature bypass aspect means that traditional security controls and network segmentation measures may be rendered ineffective against this specific attack vector.
Mitigation strategies for CVE-2016-3245 should prioritize immediate patch application through Microsoft's security updates, as the vulnerability was addressed through official Microsoft security patches released in conjunction with the vulnerability disclosure. Organizations should also implement network-level controls to restrict access to sensitive ports and services, particularly those that might be targeted through this vulnerability. Browser hardening measures including disabling unnecessary network access features and implementing strict content security policies can help reduce the attack surface. Additionally, user education and awareness programs should emphasize the importance of avoiding untrusted websites and maintaining updated browser software. This vulnerability aligns with CWE-16 (Configuration) and maps to ATT&CK technique T1071.004 (Application Layer Protocol: DNS) in the context of network protocol manipulation, highlighting the need for comprehensive security controls that address both application-level and network-level vulnerabilities.