CVE-1999-0487 in Internet Explorer
Summary
by MITRE
The DHTML Edit ActiveX control in Internet Explorer allows remote attackers to read arbitrary files.
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Analysis
by VulDB Data Team • 02/21/2025
The vulnerability identified as CVE-1999-0487 represents a critical security flaw in the DHTML Edit ActiveX control component of Microsoft Internet Explorer. This vulnerability specifically affects versions of Internet Explorer that incorporate the DHTML Edit control, which was commonly used for rich text editing functionality within web applications. The flaw stems from insufficient input validation and access control mechanisms within the ActiveX control implementation, creating a pathway for malicious actors to exploit the component's file access capabilities. The vulnerability exists at the intersection of web browser security and ActiveX control security, where client-side components can be manipulated to perform unauthorized operations. This type of vulnerability is particularly dangerous because it allows remote attackers to leverage the browser's privileges to access local system resources without proper authentication or authorization.
The technical implementation of this vulnerability involves the DHTML Edit ActiveX control's handling of file operations through its exposed interfaces and methods. Attackers can craft malicious web pages that invoke the control with specific parameters designed to bypass normal file access restrictions. The control's design flaw allows it to interpret user-supplied input as file paths or operation commands, enabling arbitrary file read operations. This typically occurs when the control fails to properly validate or sanitize input parameters before processing file system operations. The vulnerability can be exploited through cross-site scripting attacks or by hosting malicious content on compromised web servers. The control's lack of proper access controls means that legitimate web content can be manipulated to perform file system operations that should normally be restricted to authorized applications or users.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to access sensitive files stored on the victim's system. This includes configuration files, user data, application logs, and potentially system-critical files that could reveal network architecture details or authentication credentials. The vulnerability's remote exploitability means that attackers can leverage it from any location without requiring physical access to the target system. This creates a significant risk for enterprise environments where users may browse untrusted websites or encounter compromised web content. The vulnerability can be particularly dangerous in corporate environments where sensitive business data may be accessible through the affected ActiveX control, potentially leading to data breaches or further system compromise. The attack surface is expanded by the widespread use of Internet Explorer and its ActiveX controls in enterprise and personal computing environments.
Mitigation strategies for CVE-1999-0487 focus on both immediate remediation and long-term architectural improvements. The most effective immediate solution involves applying the relevant security patches provided by Microsoft, which typically include updates to the DHTML Edit ActiveX control or the complete removal of the vulnerable component from affected systems. Organizations should implement strict ActiveX control policies that limit or disable potentially vulnerable components, particularly those with file system access capabilities. Network-level controls such as firewall rules and web application firewalls can help filter out malicious content that attempts to exploit this vulnerability. The implementation of principle of least privilege access controls and regular security audits of ActiveX components can help identify and remediate similar vulnerabilities. Additionally, user education about the dangers of visiting untrusted websites and the importance of keeping software updated can reduce the likelihood of successful exploitation. This vulnerability highlights the importance of following security best practices such as those outlined in the CWE (Common Weakness Enumeration) catalog, particularly those related to input validation and access control weaknesses. The ATT&CK framework categorizes this type of vulnerability under the 'Exploitation for Privilege Escalation' and 'Initial Access' phases, emphasizing the need for comprehensive security measures that address both the technical implementation flaws and the operational security considerations.