CVE-2003-1026 in Internet Explorer
Summary
by MITRE
Internet Explorer 5.01 through 6 SP1 allows remote attackers to bypass zone restrictions via a javascript protocol URL in a sub-frame, which is added to the history list and executed in the top window's zone when the history.back (back) function is called, as demonstrated by BackToFramedJpu, aka the "Travel Log Cross Domain Vulnerability."
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Analysis
by VulDB Data Team • 01/02/2025
This vulnerability represents a critical cross-domain scripting flaw in Microsoft Internet Explorer versions 5.01 through 6 Service Pack 1 that exploits the browser's zone security model. The vulnerability stems from how Internet Explorer handles javascript protocol URLs within nested frame structures, specifically when these URLs are added to the browser's history list. When a malicious javascript URL is loaded in a sub-frame and subsequently navigated away from, the URL remains in the history stack and executes in the context of the top-level window's security zone rather than maintaining the sub-frame's original zone restrictions.
The technical implementation involves the exploitation of the history.back() method which when invoked, replays the javascript protocol URL from the history list in the context of the parent window's security domain. This creates a scenario where content originating from one security zone can execute code in another zone, effectively bypassing the zone security restrictions that are fundamental to Internet Explorer's security architecture. The vulnerability is particularly dangerous because it leverages legitimate browser functionality to achieve unauthorized cross-domain code execution, making it difficult to detect through traditional security measures.
The operational impact of this vulnerability extends beyond simple privilege escalation as it enables attackers to perform sophisticated cross-domain attacks that could compromise user sessions, steal sensitive data, or execute arbitrary code within the context of the user's current browsing session. Attackers can craft malicious web pages that embed malicious javascript in sub-frames, then use navigation techniques to trigger the execution of this code in the parent window's security context, effectively circumventing the browser's security boundaries. This vulnerability is categorized under CWE-94 as an "Improper Control of Generation of Code" and aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript" as it exploits JavaScript execution capabilities to bypass security controls.
The exploitation mechanism demonstrates a fundamental flaw in how Internet Explorer manages security zones and history navigation, where the security context of executed code does not properly respect the hierarchical frame structure. This vulnerability specifically affects the browser's history management system and its handling of javascript protocol URLs, creating a persistent security risk that remains active as long as the affected browser version is in use. The attack requires no user interaction beyond visiting a malicious website, making it particularly dangerous for widespread exploitation. Organizations using these affected versions of Internet Explorer should implement immediate mitigations including browser updates, security policy enforcement, and network-level protections to prevent exploitation of this vulnerability that could lead to complete system compromise through cross-domain scripting attacks.