CVE-2003-1027 in Internet Explorer
Summary
by MITRE
Internet Explorer 5.01 through 6 SP1 allows remote attackers to direct drag and drop behaviors and other mouse click actions to other windows by using method caching (SaveRef) to access the window.moveBy method, which is otherwise inaccessible, as demonstrated by HijackClickV2, a different vulnerability than CVE-2003-0823, aka the "Function Pointer Drag and Drop Vulnerability."
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Analysis
by VulDB Data Team • 01/02/2025
This vulnerability represents a sophisticated browser security flaw in Internet Explorer versions 5.01 through 6 Service Pack 1 that exploits method caching mechanisms to bypass security restrictions. The issue stems from how Internet Explorer handles object method references through SaveRef functionality, which creates persistent references to window methods that should normally be restricted. Attackers can leverage this behavior to manipulate drag and drop operations and mouse click actions across different windows, effectively circumventing the browser's security model that typically isolates window contexts and restricts cross-window interactions. The vulnerability specifically targets the window.moveBy method, which is normally inaccessible from external contexts due to security restrictions, but becomes exploitable through the caching mechanism.
The technical exploitation occurs through method caching where SaveRef maintains references to object methods beyond their normal scope, allowing malicious code to access window.moveBy and other restricted methods that should only be available within the same window context. This creates a pathway for attackers to perform unauthorized actions across different browser windows, enabling sophisticated attacks that can redirect user interactions and manipulate browser behavior. The flaw demonstrates how seemingly benign caching mechanisms can introduce security vulnerabilities when combined with browser object model access patterns. This vulnerability is classified under CWE-264 due to improper access control in the browser's security model, where method access restrictions are bypassed through object reference manipulation rather than direct code injection or privilege escalation.
The operational impact of this vulnerability extends beyond simple cross-window manipulation to enable more sophisticated attacks including phishing redirection, credential harvesting, and user interface manipulation. Attackers can use this vulnerability to create deceptive interfaces that appear to be legitimate browser operations while actually performing malicious actions in the background. The HijackClickV2 attack vector demonstrates how this vulnerability can be weaponized to redirect user clicks and drag operations to malicious targets, potentially leading to credential theft or unauthorized transactions. This type of vulnerability aligns with ATT&CK technique T1059.007 for script-based attacks and T1203 for exploitation for privilege escalation, as it allows attackers to extend their attack surface beyond normal browser boundaries.
Security mitigations for this vulnerability required browser vendors to implement stricter access controls for object method references and to prevent method caching from exposing restricted functionality. Microsoft addressed this issue through security updates that modified how Internet Explorer handles object references and method access across window boundaries. Organizations should have implemented browser security policies that restrict cross-window scripting and utilized security software that can detect suspicious method access patterns. The vulnerability highlighted the importance of proper object model security in web browsers and led to improved security practices in how browsers handle method references and object access control. This case study demonstrates how browser security models must account for complex interactions between object references, method caching, and cross-context access restrictions to prevent exploitation of such subtle but dangerous vulnerabilities.