CVE-2009-3016 in Safari
Summary
by MITRE
Apple Safari 4.0.3 does not properly block javascript: and data: URIs in Refresh headers in HTTP responses, which allows remote attackers to conduct cross-site scripting (XSS) attacks via vectors related to (1) injecting a Refresh header that contains a javascript: URI, (2) entering a javascript: URI when specifying the content of a Refresh header, (3) injecting a Refresh header that contains JavaScript sequences in a data:text/html URI, or (4) entering a data:text/html URI with JavaScript sequences when specifying the content of a Refresh header.
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Analysis
by VulDB Data Team • 01/18/2019
This vulnerability in Apple Safari 4.0.3 represents a critical cross-site scripting flaw that exploits improper handling of refresh headers in HTTP responses. The issue stems from Safari's insufficient validation of javascript: and data: URIs within Refresh header values, creating a pathway for malicious actors to inject harmful JavaScript code into web applications. The vulnerability specifically affects how Safari processes HTTP Refresh headers that contain URI schemes designed for executing code, fundamentally undermining the browser's security model for handling dynamic content redirection.
The technical implementation of this flaw occurs at the HTTP response parsing layer where Safari fails to adequately sanitize or block potentially dangerous URI schemes in Refresh headers. When a web server sends an HTTP response containing a Refresh header with javascript: or data:text/html URI values, Safari's parser does not properly distinguish between legitimate and malicious content. This allows attackers to craft HTTP responses that appear benign but contain embedded JavaScript payloads that execute within the victim's browser context, bypassing standard security mechanisms designed to prevent such code execution.
From an operational perspective, this vulnerability enables sophisticated cross-site scripting attacks that can compromise user sessions, steal sensitive information, or redirect users to malicious websites. Attackers can leverage this weakness by manipulating HTTP responses from compromised servers or through man-in-the-middle attacks to inject JavaScript sequences that execute automatically when users navigate to affected pages. The impact extends beyond simple XSS exploitation as it can facilitate session hijacking, credential theft, and the delivery of additional malware through the compromised browser environment.
The vulnerability aligns with CWE-79, which addresses cross-site scripting flaws in web applications, and demonstrates how browser-level security implementations can create attack vectors when they fail to properly validate input from HTTP headers. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 for JavaScript execution and T1566 for social engineering through malicious web content. The attack surface is particularly concerning as it operates at the HTTP protocol level, making it difficult for users to detect malicious activity and potentially allowing attackers to bypass traditional web application firewalls and security controls.
Mitigation strategies should focus on immediate browser updates to patched versions that properly sanitize Refresh header values and implement stricter URI validation. Organizations should also deploy network-level protections such as HTTP response filtering, web application firewalls, and content security policies that prevent execution of javascript: URIs in refresh headers. Additionally, users should be educated about the risks of visiting untrusted websites and the importance of keeping browsers updated. The vulnerability highlights the critical need for comprehensive input validation at all layers of web application security, from server-side processing to client-side parsing and execution, emphasizing that security cannot be achieved through single points of defense alone.