IIS Configuration Disclosure Scanner

Microsoft Internet Information Services (IIS) is a web server software package designed for Windows Server. It is used to host websites, services, and applications, providing a multilayered architecture to ensure scalability and security. IIS supports HTTP, HTTPS, FTP, FTPS, SMTP, and NNTP protocols, making it versatile for a range of applications. Organizations across various industries implement IIS to serve web pages securely and efficiently. Development teams utilize IIS for web application testing and deployment due to its compatibility with .NET applications. Additionally, IIS is integrated into many Windows Server environments as a standard component for web hosting.

The configuration disclosure vulnerability in IIS occurs when the server reveals information about files and directories due to the misuse of certain characters in URL requests. Specifically, the tilde character ("~") can be used to detect short names of files and folders, which should typically remain inaccessible. This vulnerability exists primarily in older .NET framework configurations and can expose critical file paths and directory names. As a result, it could aid an attacker in locating specific resources or scripts on the server. This type of vulnerability often stems from misconfigurations or legacy support features that were not properly disabled. Regular updates and configuration audits are vital to mitigate this vulnerability.

IIS suffers from a configuration disclosure issue where the short names of files and folders can be exposed via HTTP requests. This vulnerability can be observed when using specific request patterns that include the tilde character. The malformed requests might not return a typical 404 status code as they do with valid resources, thereby confirming the presence of hidden files. Attackers can exploit this by systematically guessing and validating the short paths to discover files they should not access. The problem is exacerbated if the server has verbose error responses enabled or if additional information is inadvertently exposed in headers. It highlights the importance of minimizing information leakage through headers and response codes.

Exploitation of this vulnerability can assist malicious actors in mapping sensitive server infrastructure, making it easier to exploit other vulnerabilities. By identifying hidden files or directories, attackers can gather more information for conducting more targeted attacks or data breach operations. Accessing such short-named files may contain credentials, configuration details, or scripts that could lead to privilege escalation. It poses a significant threat to the confidentiality and integrity of the data stored on the server. In worst-case scenarios, it may lead to complete server compromise if critical files are exposed.

REFERENCES

• https://github.com/irsdl/IIS-ShortName-Scanner
• https://github.com/lijiejie/IIS_shortname_Scanner
• https://www.exploit-db.com/exploits/19525
• http://soroush.secproject.com/blog/2012/06/microsoft-iis-tilde-character-vulnerabilityfeature-short-filefolder-name-disclosure/