CVE-2010-5069 in Chrome
Summary
by MITRE
The Cascading Style Sheets (CSS) implementation in Google Chrome 4 does not properly handle the :visited pseudo-class, which allows remote attackers to obtain sensitive information about visited web pages via a crafted HTML document. NOTE: this may overlap CVE-2010-2264.
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Analysis
by VulDB Data Team • 02/13/2019
The vulnerability described in CVE-2010-5069 represents a significant security flaw in Google Chrome version 4's CSS implementation that specifically affects how the browser handles the :visited pseudo-class. This particular weakness arises from the browser's insufficient handling of CSS selectors that target visited links, creating a potential avenue for malicious actors to exploit the browser's rendering engine and extract sensitive information about a user's browsing history. The issue stems from the fundamental way Chrome processes CSS rules that interact with the visited state of hyperlinks, allowing attackers to craft HTML documents that can reveal whether specific URLs have been visited by the user.
The technical exploitation of this vulnerability occurs through the manipulation of CSS properties that can detect visited states through visual styling and measurement techniques. Attackers can construct malicious HTML documents that use CSS rules to determine if a user has visited certain web pages by measuring the visual properties of links that have been marked as visited. This approach leverages the fact that browsers typically apply different styling to visited versus unvisited links, and when these visual differences can be measured programmatically, they provide a means of inferring user behavior and browsing patterns. The vulnerability specifically impacts the CSS rendering engine's interpretation of the :visited pseudo-class, which is designed to allow web developers to style visited links differently from unvisited ones, but in this case, the implementation fails to properly isolate these visual indicators from malicious inspection.
The operational impact of this vulnerability extends beyond simple privacy concerns to potentially expose sensitive user information that could be used for targeted attacks or social engineering campaigns. When an attacker successfully exploits this vulnerability, they can gain knowledge about a user's browsing habits, including which websites they have visited, potentially revealing personal information, professional interests, or even confidential activities. This type of information leakage can be particularly damaging in corporate environments where users may be browsing sensitive business information, or in personal contexts where users may be researching sensitive topics such as medical conditions, legal issues, or financial matters. The vulnerability essentially creates a covert channel through which malicious actors can gather intelligence about user behavior without explicit user consent or awareness.
The security implications of this vulnerability align with several established frameworks and threat models, particularly those related to browser-based reconnaissance and information leakage. This issue can be categorized under CWE-200, which addresses "Information Exposure," and represents a form of side-channel attack where the attacker uses indirect methods to extract information. From an ATT&CK perspective, this vulnerability enables techniques related to reconnaissance and credential access, specifically the use of browser-based reconnaissance to gather intelligence about user activities. The vulnerability also relates to the broader category of cross-site scripting and information disclosure attacks that target browser implementations rather than web applications directly. Mitigation strategies for this vulnerability would typically involve updating to a patched version of Chrome that properly handles the :visited pseudo-class, implementing browser security policies that limit CSS-based information leakage, and potentially using browser extensions or security software that can detect and block such malicious CSS behaviors. Organizations should also consider implementing network-level monitoring to detect potential exploitation attempts and ensure that users are regularly updated with the latest security patches to protect against known vulnerabilities in their web browsers.