CVE-2010-3327 in Internet Explorer
Summary
by MITRE
The implementation of HTML content creation in Microsoft Internet Explorer 6 through 8 does not remove the Anchor element during pasting and editing, which might allow remote attackers to obtain sensitive deleted information by visiting a web page, aka "Anchor Element Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 09/26/2021
The vulnerability identified as CVE-2010-3327 represents a critical information disclosure flaw in Microsoft Internet Explorer versions 6 through 8 that specifically affects the handling of HTML content during paste and edit operations. This vulnerability stems from the improper management of Anchor elements within the browser's HTML content creation implementation, creating a scenario where sensitive information that should have been deleted or removed can potentially be recovered through malicious web page content. The flaw operates at the core rendering engine level where the browser fails to properly sanitize HTML content during editing operations, particularly when dealing with anchor tags that contain sensitive data.
The technical implementation of this vulnerability involves the browser's contenteditable functionality and HTML parsing mechanisms that do not adequately strip or sanitize Anchor elements during paste operations. When users paste content into editable fields or when the browser processes HTML content that includes anchor tags, the implementation fails to completely remove these elements from memory or display, potentially leaving traces of deleted information accessible through specific web page interactions. This behavior creates a persistent information leakage vector where previously deleted content can be reconstructed or accessed through crafted web pages that exploit the browser's handling of anchor elements. The vulnerability specifically manifests when attackers craft web pages that trigger the browser to process and display anchor elements that contain sensitive information, allowing the recovery of deleted content through browser rendering mechanisms.
The operational impact of CVE-2010-3327 extends beyond simple information disclosure, as it can enable attackers to recover deleted sensitive data such as personal information, passwords, or confidential communications that were previously thought to be removed from web forms or editable content areas. This vulnerability particularly affects users who frequently interact with web forms, email clients, or any application that utilizes rich text editing capabilities within Internet Explorer. The attack surface is broad since the vulnerability exists across multiple versions of Internet Explorer 6 through 8, making it particularly dangerous for organizations that have not fully migrated away from these legacy browsers. The vulnerability can be exploited through simple web page visits without requiring any additional user interaction beyond navigating to a malicious site, making it particularly insidious for social engineering attacks where users might be tricked into visiting compromised websites.
Security researchers have classified this vulnerability under CWE-200, which specifically addresses Information Exposure, and it aligns with ATT&CK technique T1566 for Initial Access through Spearphishing Attachments or Links. The vulnerability demonstrates the importance of proper HTML sanitization and content management in web browsers, particularly when handling user-generated content and editing operations. Organizations should implement immediate mitigations including browser updates, patch management, and user education about avoiding untrusted web content. The vulnerability also highlights the need for comprehensive security testing of browser rendering engines and HTML content processing capabilities to identify similar information disclosure flaws in other browser implementations.
Microsoft addressed this vulnerability through security updates that improved the HTML content creation implementation to properly handle Anchor elements during paste and editing operations, ensuring that sensitive information is completely removed from memory and display when users delete content. The fix specifically targets the contenteditable functionality and HTML parsing mechanisms that were responsible for the improper handling of anchor elements, requiring users to apply the relevant security patches to protect against exploitation. This vulnerability serves as a critical reminder of the importance of proper HTML sanitization and content management in web browsers, particularly in legacy implementations where security updates may not be regularly applied.