CVE-1999-1472 in Internet Explorer
Summary
by MITRE
Internet Explorer 4.0 allows remote attackers to read arbitrary text and HTML files on the user's machine via a small IFRAME that uses Dynamic HTML (DHTML) to send the data to the attacker, aka the Freiburg text-viewing issue.
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Analysis
by VulDB Data Team • 04/20/2026
The CVE-1999-1472 vulnerability represents a critical security flaw in Internet Explorer 4.0 that exploited the browser's handling of dynamic html content through iframe elements. This vulnerability specifically targeted the browser's implementation of dynamic html capabilities and demonstrated how attackers could leverage these features to execute unauthorized file access operations on victim machines. The issue was particularly concerning because it allowed remote threat actors to bypass normal file system access restrictions and retrieve sensitive information from users' local systems. The vulnerability was categorized under the broader class of cross-site scripting attacks and highlighted the dangerous implications of dynamic html processing in web browsers. Security researchers identified this as a significant risk to user privacy and system integrity, particularly in environments where users might encounter malicious web content.
The technical exploitation mechanism relied on a small iframe element that utilized dynamic html capabilities to perform unauthorized file operations on the victim's machine. Attackers could craft malicious html pages that contained embedded iframe elements with specific dynamic html properties that would trigger file reading operations when the page was loaded. The vulnerability exploited the browser's failure to properly validate or restrict access to local file system resources through dynamic html constructs. This particular implementation allowed attackers to read arbitrary text and html files from the user's local machine, potentially exposing sensitive documents, configuration files, or other locally stored information. The attack vector specifically targeted the browser's handling of DHTML (Dynamic HTML) elements within iframe contexts, demonstrating how legitimate browser features could be abused for malicious purposes. The flaw essentially created a path for attackers to access local files through what should have been restricted browser operations.
The operational impact of CVE-1999-1472 was substantial and far-reaching across the internet community during the late 1990s. This vulnerability allowed attackers to potentially access sensitive user data including personal documents, configuration files, and other locally stored information without user knowledge or consent. The attack could be executed remotely through web pages, making it particularly dangerous for users who browsed the internet without proper security measures. The vulnerability was classified under CWE-20 as a weakness in input validation, specifically related to improper handling of dynamic html content and file system access controls. Organizations and individual users faced significant risks of data exposure and potential identity theft. The attack could be particularly effective in phishing campaigns or when users visited compromised websites, as the vulnerability did not require any special user interaction beyond visiting the malicious page. Security professionals noted this as a prime example of how browser-based attacks could circumvent traditional network security controls and directly access local system resources.
Mitigation strategies for CVE-1999-1472 focused primarily on updating to patched versions of Internet Explorer and implementing proper browser security configurations. Microsoft released patches to address the vulnerability in subsequent updates to Internet Explorer 4.0 and later versions. Organizations should have implemented browser security policies that restricted the execution of dynamic html content from untrusted sources. Network administrators needed to consider implementing web content filtering solutions that could detect and block malicious iframe content. The vulnerability highlighted the importance of proper input validation and access control mechanisms within web browsers. Security professionals recommended disabling dynamic html features when not required for legitimate business operations. This vulnerability also underscored the need for comprehensive web application security testing and the importance of understanding how browser features could be misused in attack scenarios. The incident contributed to the development of more robust browser security models and influenced the evolution of modern web security standards and practices. The attack pattern associated with this vulnerability was later categorized in the ATT&CK framework under techniques related to credential access and privilege escalation through browser-based attacks.