CVE-2004-1173 in Internet Explorer
Summary
by MITRE
Internet Explorer 6 allows remote attackers to bypass the popup blocker via the document object model (DOM) methods in the DHTML Dynamic HTML (DHTML) Editing Component (DEC) and Javascript that calls showModalDialog.
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Analysis
by VulDB Data Team • 05/07/2019
This vulnerability resides in the Internet Explorer 6 browser implementation and represents a significant bypass of security controls designed to protect users from unwanted popup windows. The issue specifically targets the popup blocker mechanism that was introduced to mitigate malicious popup attacks and unwanted advertising content. Attackers can exploit this flaw by leveraging the Document Object Model (DOM) methods within the DHTML Dynamic HTML (DHTML) Editing Component to execute JavaScript code that invokes the showModalDialog function, thereby circumventing the browser's built-in popup restrictions. The vulnerability demonstrates a fundamental flaw in how the browser handles certain DOM interactions and JavaScript execution contexts that should have been properly constrained by the popup blocking policies.
The technical implementation of this attack involves exploiting the interaction between the DHTML Editing Component and JavaScript's showModalDialog method, which creates a modal dialog box that can bypass the standard popup blocker restrictions. This occurs because the browser's security model fails to properly distinguish between legitimate and malicious uses of the showModalDialog function when invoked through specific DOM manipulation sequences. The vulnerability specifically affects Internet Explorer 6 and represents a classic case of insufficient input validation and context awareness in the browser's security architecture. The DHTML Editing Component's DOM methods provide an attack surface where JavaScript code can manipulate the browser's window management behavior in ways that were not anticipated by the popup blocker implementation.
From an operational perspective, this vulnerability allows remote attackers to execute malicious code that can display unwanted windows, potentially leading to phishing attacks, malware delivery, or other social engineering exploits. The attack can be particularly dangerous because it operates silently in the background without user awareness, as the popup blocker is effectively bypassed. This creates a vector for delivering malicious content through seemingly legitimate web applications that may be used for corporate or personal browsing. The vulnerability can be exploited through various attack vectors including malicious websites, compromised web applications, or social engineering campaigns that trick users into visiting malicious pages. The impact extends beyond simple annoyance to potential security breaches that could compromise user data and system integrity.
Organizations should implement immediate mitigations including browser updates to newer versions of Internet Explorer that address this vulnerability, or migration to more secure browser alternatives that do not exhibit this flaw. System administrators should consider implementing additional security measures such as browser hardening configurations, network-level filtering to block malicious domains, and user education about the risks of visiting untrusted websites. The vulnerability aligns with CWE-611 (Improper Restriction of XML External Entity Reference) and related weakness patterns that involve improper handling of external references and security context violations. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 (Command and Scripting Interpreter: JavaScript) and T1203 (Exploitation for Client Execution) categories, representing how attackers can leverage scripting languages to execute malicious payloads and bypass client-side security controls. Organizations should also consider implementing security policies that restrict the use of showModalDialog and similar functions in enterprise environments where such attacks could pose significant risks to operational security and data protection.