CVE-2012-6463 in Web Browser
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Opera before 12.10 allows remote attackers to inject arbitrary web script or HTML via vectors involving an unspecified sequence of loading of documents and loading of data: URLs.
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Analysis
by VulDB Data Team • 12/21/2021
The vulnerability identified as CVE-2012-6463 represents a cross-site scripting flaw in Opera web browsers prior to version 12.10, specifically manifesting in the browser's handling of document loading sequences and data URL processing. This weakness stems from inadequate input validation and sanitization mechanisms within Opera's rendering engine, which fails to properly escape or filter malicious content when processing certain combinations of document loads and data URL requests. The vulnerability operates through an unspecified sequence involving the loading of documents and data URLs, creating a condition where attacker-controlled content can be executed within the context of a user's browsing session.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious web content that leverages Opera's document loading behavior to inject arbitrary script code or HTML elements. The flaw exploits the browser's handling of data URLs, which are designed to embed small data items directly within the URL itself, typically used for images or other resources. When Opera processes these URLs in conjunction with specific document loading sequences, the browser fails to adequately sanitize the content, allowing malicious scripts to execute in the context of the user's session. This type of vulnerability falls under CWE-79, which specifically addresses cross-site scripting flaws where untrusted data is improperly incorporated into web pages without proper validation or escaping mechanisms.
The operational impact of this vulnerability extends beyond simple script execution, potentially enabling attackers to perform session hijacking, defacement of web pages, or redirection to malicious sites. An attacker could craft phishing pages that appear legitimate to users while simultaneously executing malicious scripts that steal cookies, capture user credentials, or modify page content. The vulnerability's exploitation requires remote access and can be accomplished through various vectors including malicious websites, email attachments, or compromised web services that serve content to Opera users. Users who browse to malicious sites or click on compromised links could unknowingly execute attacker-controlled code within their browser environment.
Mitigation strategies for this vulnerability include immediate upgrading to Opera version 12.10 or later, which contains the necessary patches to address the document loading and data URL processing flaws. System administrators should implement comprehensive browser update policies and ensure all users maintain current versions of their web browsers. Additionally, organizations can deploy web application firewalls and content filtering solutions that can detect and block suspicious script execution patterns. The vulnerability demonstrates the importance of proper input validation and the need for browsers to maintain robust sanitization mechanisms when processing data URLs and handling complex document loading sequences. From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1059.007 for scripting and T1566 for credential access, emphasizing the need for layered defensive measures including regular security updates, user education, and monitoring for suspicious browser behavior.