CVE-2011-0219 in Safari
Summary
by MITRE
Apple Safari before 5.0.6 allows remote attackers to bypass the Same Origin Policy, and modify the rendering of text from arbitrary web sites, via a Java applet that loads fonts.
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Analysis
by VulDB Data Team • 11/15/2021
The vulnerability identified as CVE-2011-0219 represents a critical security flaw in Apple Safari web browser versions prior to 5.0.6 that fundamentally undermines the browser's core security model. This vulnerability specifically targets the Same Origin Policy, which serves as one of the fundamental security mechanisms in web browsers designed to prevent malicious websites from accessing or manipulating content from different origins. The flaw enables attackers to bypass these critical protections through a sophisticated attack vector involving Java applets and font loading mechanisms, creating a pathway for cross-site scripting and content manipulation attacks.
The technical exploitation of this vulnerability occurs through a Java applet that leverages font loading capabilities to manipulate how text renders within the browser environment. When Safari processes a Java applet that loads fonts from external sources, the browser fails to properly enforce origin restrictions during the font rendering process. This allows malicious actors to craft Java applets that can access and modify text content from arbitrary websites, effectively breaking the isolation that should exist between different web origins. The vulnerability stems from insufficient validation of font sources and inadequate enforcement of cross-origin restrictions during the rendering pipeline, creating a direct pathway for attackers to circumvent browser security boundaries.
The operational impact of this vulnerability extends beyond simple content manipulation to encompass serious security implications for users browsing the web. Attackers could potentially inject malicious content into legitimate websites, modify displayed text in real-time, or even execute more sophisticated attacks by leveraging the ability to manipulate rendered content. This capability significantly increases the risk of phishing attacks, data corruption, and user deception since attackers can modify the visual presentation of web pages without requiring direct access to the underlying server content. The vulnerability affects users across all operating systems where affected Safari versions are installed, creating widespread exposure across the user base.
Security professionals should recognize this vulnerability as a classic example of a Same Origin Policy bypass, which aligns with CWE-94 in the Common Weakness Enumeration catalog that covers improper control of generation of code. The attack pattern described here also corresponds to techniques documented in the MITRE ATT&CK framework under the T1059.007 sub-technique for "Command and Scripting Interpreter: PowerShell" and similar execution methods that leverage browser-based exploits. Organizations should immediately implement patch management protocols to upgrade to Safari 5.0.6 or later versions that contain the necessary security fixes. Additional mitigations include implementing strict content security policies, disabling Java applets in web browsers, and employing network monitoring solutions to detect suspicious font loading activities that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of maintaining up-to-date browser software and highlights the ongoing challenges in securing complex web rendering engines against sophisticated cross-origin attacks.