CVE-1999-1453 in Internet Explorer
Summary
by MITRE
Internet Explorer 4 allows remote attackers (malicious web site operators) to read the contents of the clipboard via the Internet WebBrowser ActiveX object.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 02/17/2025
This vulnerability resides in the Internet Explorer 4 web browser which was released in 1999 as part of Microsofts Windows 95 and Windows NT operating systems. The flaw specifically affects the WebBrowser ActiveX control that enables web pages to interact with the browser's functionality. The vulnerability stems from insufficient input validation and access control mechanisms within the ActiveX object implementation that allows malicious websites to programmatically access clipboard contents through scripting interfaces. This represents a classic case of improper access control where the browser fails to properly sandbox ActiveX controls, allowing them to perform operations that should be restricted to local applications only.
The technical exploitation occurs through the use of JavaScript or VBScript code embedded in malicious web pages that leverages the WebBrowser ActiveX control to access the clipboard functionality. When a user visits a compromised website, the malicious code can execute commands that read the contents of the clipboard without user consent or awareness. The vulnerability specifically targets the clipboard data access methods exposed by the ActiveX object, bypassing normal security boundaries that should prevent remote code from accessing system resources. This type of attack falls under the CWE-255 weakness category, which deals with credentials management issues, and more specifically relates to improper access control mechanisms. The vulnerability demonstrates a critical failure in the principle of least privilege where remote web content should not have access to local system resources such as clipboard data.
The operational impact of this vulnerability is significant as it allows attackers to harvest sensitive information that users have copied to their clipboard. This includes but is not limited to passwords, personal identification numbers, private keys, confidential documents, and other sensitive data that users may have copied for legitimate purposes. The attack vector is particularly dangerous because it requires no special privileges from the user and can be executed automatically when visiting a malicious website. The vulnerability creates a persistent threat where users may unknowingly expose their clipboard contents to remote attackers, potentially leading to credential theft, data breaches, and unauthorized access to systems. This aligns with the ATT&CK technique T1113 which covers screen capture and clipboard data collection, making it a critical threat vector in the broader context of information gathering and exfiltration.
Mitigation strategies for this vulnerability include immediate patching of Internet Explorer 4 installations, which was the primary solution provided by Microsoft. Users should also implement browser security settings that restrict ActiveX control usage and disable automatic execution of scripts from untrusted sources. Network administrators should consider implementing web filtering solutions that block access to known malicious domains and establish security policies that limit ActiveX control permissions. The vulnerability highlights the importance of sandboxing and privilege separation in browser architecture, leading to improved security models in subsequent browser versions. Organizations should also implement user education programs to raise awareness about the risks of visiting untrusted websites and the importance of keeping browser software updated. This vulnerability contributed to the broader understanding of ActiveX security risks and influenced the development of more secure web browser architectures that separate web content execution from system-level access. The incident demonstrated the critical need for proper input validation and access control in component-based architectures, particularly when dealing with user-facing interfaces that may be exposed to remote content.