CVE-2017-8736 in Internet Explorer
Summary
by MITRE
Internet Explorer in Microsoft Windows 7 SP1, Windows Server 2008 R2 SP1, Windows 8.1 and Windows RT 8.1, Windows Server 2012 R2, and Microsoft Edge and Internet Explorer in Windows 10 Gold, 1511, 1607, 1703, and Windows Server 2016 allow an attacker to obtain specific information used in the parent domain, due to Microsoft browser parent domain verification in certain functionality, aka "Microsoft Browser Information Disclosure Vulnerability".
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Analysis
by VulDB Data Team • 01/12/2021
This vulnerability represents a critical information disclosure flaw in Microsoft browsers that exploits domain verification mechanisms to expose sensitive data across parent domain boundaries. The issue affects multiple versions of Internet Explorer and Microsoft Edge across various Windows operating systems, specifically targeting the way these browsers handle parent domain verification processes. When certain browser functionalities encounter domain validation scenarios, the implementation contains a flaw that allows attackers to access information that should remain isolated within specific domain contexts.
The technical root cause stems from improper handling of domain verification routines within Microsoft's browser implementation, where the security boundaries between parent and child domains are not properly enforced. This vulnerability operates through a specific attack vector that leverages the browser's internal domain checking mechanisms, enabling an attacker to extract information that should be restricted to the parent domain context. The flaw manifests when the browser processes certain web content or navigation scenarios that trigger domain verification checks, creating an information leak channel that bypasses normal security restrictions.
From an operational impact perspective, this vulnerability presents significant risks to enterprise environments where multiple domains and subdomains are utilized for security separation. Attackers can exploit this flaw to gain access to sensitive information that may include session tokens, authentication data, or other domain-specific resources that should remain isolated. The vulnerability's presence across multiple browser versions and operating systems increases its attack surface, making it particularly dangerous for organizations with diverse Windows environments. The information disclosure could potentially enable further attacks such as cross-site scripting exploitation, session hijacking, or privilege escalation within the affected domains.
Security professionals should note that this vulnerability aligns with CWE-200, which addresses information exposure, and relates to ATT&CK technique T1059 for execution through web browsers. The flaw represents a classic case of insufficient domain isolation in browser security implementations, where the boundary checking mechanisms fail to properly validate domain relationships. Organizations should prioritize immediate patching of affected systems, as the vulnerability can be exploited remotely without user interaction, making it particularly dangerous in targeted attack scenarios. Additionally, network segmentation and web application firewalls should be implemented to limit potential information leakage, while monitoring for suspicious domain access patterns can help detect exploitation attempts. The vulnerability highlights the importance of proper security boundary enforcement in browser implementations and demonstrates how seemingly minor implementation flaws can result in significant information disclosure risks across enterprise environments.