CVE-1999-0738 in IIS
Summary
by MITRE
The code.asp sample file in IIS and Site Server allows remote attackers to read arbitrary files.
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Analysis
by VulDB Data Team • 10/23/2025
The vulnerability identified as CVE-1999-0738 represents a critical security flaw in Microsoft Internet Information Services and Microsoft Site Server products. This issue specifically affects the code.asp sample file which was included as part of the default installation packages for these web server platforms. The vulnerability stems from inadequate input validation and improper access controls within the sample application, creating a path for malicious actors to exploit the system's file reading capabilities. The flaw exists at the application level where user-supplied input is not properly sanitized before being processed by the web server's scripting engine. This vulnerability falls under the category of insecure direct object reference as defined by CWE-22, where the application provides direct access to objects based on user-supplied input without proper authorization checks. The issue is particularly dangerous because it allows remote attackers to traverse the file system and access arbitrary files on the server, potentially exposing sensitive data, configuration files, and system resources.
The technical implementation of this vulnerability involves the manipulation of input parameters within the code.asp sample file to bypass normal file access restrictions. Attackers can exploit this by crafting specific requests that target the vulnerable script, enabling them to read files that should normally be restricted to authorized users only. The exploitation process typically involves passing malicious file paths or directory traversal sequences through the web application's interface, which then gets processed by the server-side scripting engine without adequate validation. This type of vulnerability aligns with the ATT&CK technique T1213.002 for Data from Information Repositories, as attackers can systematically extract data from the compromised system. The vulnerability's impact extends beyond simple file reading, as it can potentially allow attackers to access sensitive configuration files, database connection strings, and other critical system information that could be used for further exploitation.
The operational impact of CVE-1999-0738 is severe and multifaceted, affecting organizations that deploy vulnerable IIS or Site Server installations. System administrators may face unauthorized access to confidential data, including user credentials, application source code, and business-critical information stored on the web server. The vulnerability can also serve as a stepping stone for more sophisticated attacks, allowing threat actors to gather intelligence about the target environment and identify additional vulnerabilities within the network infrastructure. Organizations may experience regulatory compliance violations, data breaches, and potential legal consequences depending on the nature of the information accessed through this vulnerability. The risk is compounded by the fact that this vulnerability affects widely deployed web server software, making it an attractive target for automated exploitation tools and broad-based attack campaigns. The vulnerability's exploitation does not require specialized knowledge or tools, making it particularly dangerous as it can be leveraged by threat actors of varying skill levels.
Mitigation strategies for CVE-1999-0738 should focus on immediate remediation and long-term security hardening measures. Organizations should immediately remove or secure the vulnerable code.asp sample files from production environments, as these files are typically included for demonstration purposes only and should not be accessible in live systems. Implementing proper input validation and sanitization mechanisms is crucial to prevent similar vulnerabilities from occurring in custom applications. Network segmentation and access control measures should be enforced to limit access to web server resources, while regular security audits and vulnerability assessments should be conducted to identify and remediate similar issues. System administrators should also implement proper file permission controls and ensure that web server processes run with minimal required privileges. The remediation process should include comprehensive testing to verify that legitimate functionality remains intact while eliminating the attack vectors that enable this vulnerability. Additionally, organizations should establish robust patch management processes to ensure timely updates of web server software and related components to prevent exploitation of known vulnerabilities.