CVE-2009-3263 in Chrome
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Google Chrome 2.x and 3.x before 3.0.195.21 allows remote attackers to inject arbitrary web script or HTML via a (1) RSS or (2) Atom feed, related to the rendering of the application/rss+xml content type as XML "active content."
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Analysis
by VulDB Data Team • 08/22/2021
The vulnerability described in CVE-2009-3263 represents a critical cross-site scripting flaw that affected Google Chrome versions 2.x and 3.x prior to version 3.0.195.21. This security weakness specifically targeted the browser's handling of RSS and Atom feed content types, creating a pathway for remote attackers to execute malicious scripts within the context of the user's browsing session. The vulnerability stems from Chrome's improper handling of application/rss+xml content type rendering, where the browser treated RSS and Atom feeds as XML active content, thereby exposing users to potential script injection attacks.
The technical flaw manifests when Chrome processes RSS or Atom feeds that contain malicious script code within their XML structure. When these feeds are rendered in the browser, the XML parser processes the active content without adequate sanitization or context validation, allowing attackers to embed JavaScript code or HTML elements that execute automatically when users view the feed. This behavior creates a vector for attackers to exploit the browser's XML processing capabilities and inject malicious payloads that can persistently execute within the user's browser environment. The vulnerability is particularly dangerous because it leverages legitimate content types that users might expect to be safe, making social engineering attacks more effective.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, data exfiltration, and redirection to malicious websites. Users who browse RSS or Atom feeds from untrusted sources become potential victims, as the vulnerability operates at the browser rendering level rather than requiring user interaction with malicious links or downloads. The attack surface is broad since RSS and Atom feeds are commonly used for news aggregation, blog updates, and content syndication across various websites, making this vulnerability particularly widespread in its potential exploitation scope.
This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications, and demonstrates the importance of proper input validation and output encoding in web browsers. The issue also relates to ATT&CK technique T1566, which covers social engineering tactics involving the delivery of malicious content through trusted channels. The affected Chrome versions represent a critical security gap in the browser's content security model, where the distinction between trusted and untrusted content was insufficiently enforced during XML processing. Organizations and users should have implemented immediate mitigations including browser updates, feed reader restrictions, and network-based filtering to prevent exploitation of this vulnerability while awaiting the official security patch that addressed the XML content handling behavior.
The remediation approach for this vulnerability required immediate deployment of Chrome version 3.0.195.21 or later, which corrected the XML content type handling and implemented proper sanitization of RSS and Atom feed data before rendering. Security practitioners should have monitored for similar vulnerabilities in feed processing components and maintained updated threat intelligence on browser-based XSS exploits. The incident highlighted the need for comprehensive content security policies and the importance of validating all incoming content types, particularly those that might be processed as active content within web browsers.