CVE-2003-0816 in Internet Explorer
Summary
by MITRE
Internet Explorer 6 SP1 and earlier allows remote attackers to bypass zone restrictions by (1) using the NavigateAndFind method to load a file: URL containing Javascript, as demonstrated by NAFfileJPU, (2) using the window.open method to load a file: URL containing Javascript, as demonstrated using WsOpenFileJPU, (3) setting the href property in the base tag for the _search window, as demonstrated using WsBASEjpu, (4) loading the search window into an Iframe, as demonstrated using WsFakeSrc, (5) caching a javascript: URL in the browser history, then accessing that URL in the same frame as the target domain, as demonstrated using WsOpenJpuInHistory, NAFjpuInHistory, BackMyParent, BackMyParent2, and RefBack, aka the "Script URLs Cross Domain" vulnerability.
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Analysis
by VulDB Data Team • 03/30/2025
The CVE-2003-0816 vulnerability represents a critical cross-domain scripting flaw in Internet Explorer 6 Service Pack 1 and earlier versions that fundamentally undermines the browser's security model. This vulnerability operates by exploiting the browser's zone security restrictions, which are designed to prevent malicious code from executing across different trust domains. The flaw specifically targets the handling of script URLs and file:// protocol access, allowing attackers to circumvent the security boundaries that separate local and internet zones. The vulnerability is categorized under CWE-264 as a permissions, privileges, and access control weakness, demonstrating how improper handling of URL protocols can lead to privilege escalation.
The technical exploitation of this vulnerability occurs through multiple attack vectors that leverage different browser APIs and DOM manipulation techniques. The NavigateAndFind method allows attackers to load file: URLs containing JavaScript code, while window.open enables similar execution through the opening of new windows with malicious file:// URLs. The base tag href property manipulation creates a persistent threat by setting the search window's location to JavaScript content. Additionally, the iframe loading technique and browser history caching mechanisms provide alternative pathways for executing malicious scripts across domain boundaries. These methods collectively demonstrate the vulnerability's sophistication in bypassing multiple layers of security controls that should prevent cross-domain script execution.
The operational impact of this vulnerability is severe as it enables attackers to execute arbitrary JavaScript code in the context of different security zones, potentially allowing for complete browser compromise. Attackers can leverage these techniques to steal session cookies, access local files, perform actions on behalf of users, and ultimately gain unauthorized access to systems. The vulnerability particularly affects environments where users have mixed trust levels, as it allows malicious code from less trusted zones to execute within more privileged contexts. This cross-domain scripting capability aligns with ATT&CK technique T1059.007 for script-based execution and T1566 for social engineering, as the vulnerability often requires user interaction to be exploited successfully.
Mitigation strategies for CVE-2003-0816 focus on both immediate patching and operational security measures. Microsoft released security updates that addressed the core issue by tightening the restrictions on file:// URL handling and script execution across different security zones. Organizations should implement the latest security patches for Internet Explorer and consider migrating to more secure browser alternatives. Additional protective measures include disabling the NavigateAndFind method, restricting the use of window.open with file:// URLs, and implementing strict content security policies. Network-level protections such as web application firewalls and browser security extensions can provide additional defense in depth. The vulnerability highlights the importance of maintaining up-to-date security patches and demonstrates how legacy browser security models can contain fundamental flaws that require comprehensive remediation rather than simple configuration changes.