CVE-2009-2200 in Safari
Summary
by MITRE
WebKit in Apple Safari before 4.0.3 does not properly restrict the URL scheme of the pluginspage attribute of an EMBED element, which allows user-assisted remote attackers to launch arbitrary file: URLs and obtain sensitive information via a crafted HTML document.
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Analysis
by VulDB Data Team • 04/06/2025
The vulnerability identified as CVE-2009-2200 resides within the WebKit rendering engine component of Apple Safari browsers prior to version 4.0.3. This security flaw specifically targets the handling of the pluginspage attribute within EMBED HTML elements, demonstrating a critical weakness in the browser's security model for processing web content. The issue represents a classic case of improper input validation and scheme restriction that could be exploited by malicious actors to gain unauthorized access to system resources. The vulnerability falls under the category of information disclosure and privilege escalation, as it allows attackers to bypass normal security boundaries that should prevent access to local file systems.
The technical implementation of this vulnerability stems from WebKit's insufficient validation of URL schemes when processing the pluginspage attribute of EMBED elements. When a web page contains an EMBED tag with a malicious pluginspage attribute value, the browser fails to properly validate whether the specified URL scheme is permitted. This allows attackers to specify file: URLs that would normally be restricted by browser security policies, effectively circumventing the security mechanisms designed to prevent local file access. The flaw occurs during the parsing and processing of HTML elements, where the browser's security model does not adequately enforce scheme restrictions for plugin loading mechanisms. This type of vulnerability is categorized as CWE-20, which represents Improper Input Validation, and specifically relates to CWE-74, which deals with Improper Neutralization of Special Elements in Output Used by a Downstream Component.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a potential pathway for more serious attacks. Remote attackers can craft malicious HTML documents that, when viewed in affected Safari versions, automatically attempt to load plugins from local file paths. This capability enables attackers to access sensitive files that would normally be protected by the browser's security model, including user data, configuration files, and potentially system files. The user-assisted nature of the attack means that victims must view the malicious page, but the attack does not require any special privileges or complex exploitation techniques. This makes the vulnerability particularly dangerous in social engineering scenarios where users might be tricked into visiting compromised websites. The attack vector aligns with ATT&CK technique T1059.005, which covers Command and Scripting Interpreter: Visual Basic, and represents a form of client-side exploitation that leverages browser security weaknesses.
Mitigation strategies for this vulnerability focus on immediate browser updates and implementation of additional security controls. The primary and most effective solution is upgrading to Safari version 4.0.3 or later, which includes the necessary patches to properly validate URL schemes in EMBED elements. Organizations should also implement web content filtering solutions that can detect and block malicious HTML content containing suspicious EMBED tags with file: URLs. Network-level protections such as web application firewalls can help identify and prevent exploitation attempts by monitoring for patterns associated with this vulnerability. Additionally, users should be educated about the risks of visiting untrusted websites and the importance of keeping their browsers updated. Security configurations should include restrictions on local file access permissions for web browsers and implementation of sandboxing mechanisms that limit the browser's ability to access system resources. The vulnerability demonstrates the importance of comprehensive input validation and the need for robust security models in browser engines, as it shows how a single flaw in URL scheme handling can lead to significant information disclosure risks.