CVE-1999-1375 in IIS
Summary
by MITRE
FileSystemObject (FSO) in the showfile.asp Active Server Page (ASP) allows remote attackers to read arbitrary files by specifying the name in the file parameter.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 12/08/2024
The vulnerability identified as CVE-1999-1375 represents a critical directory traversal flaw within the FileSystemObject component of Microsoft Internet Information Services when processing Active Server Pages. This weakness exists in the showfile.asp page which accepts user input through the file parameter without proper validation or sanitization. The vulnerability allows remote attackers to access arbitrary files on the server by manipulating the file parameter to navigate through the file system hierarchy.
The technical root cause of this vulnerability stems from improper input validation within the ASP application layer. When the showfile.asp page processes the file parameter, it directly incorporates user-supplied data into file system operations without implementing adequate security controls. This design flaw enables attackers to exploit the FileSystemObject's capabilities by constructing malicious file paths that bypass normal access controls. The vulnerability specifically affects the way the FSO component handles file operations, where it accepts relative paths and directory traversal sequences such as ../ or ..\ that allow access to files outside the intended directory structure.
From an operational impact perspective, this vulnerability presents a severe threat to information security as it enables unauthorized data access and potential information disclosure. Attackers can leverage this flaw to read sensitive files including configuration files, database connection strings, application source code, and other confidential data stored on the web server. The vulnerability affects systems running vulnerable versions of IIS and ASP components, potentially compromising entire web applications and underlying server resources. The impact extends beyond simple file reading as it can lead to complete system compromise when combined with other exploitation techniques.
Security professionals should note that this vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The ATT&CK framework categorizes this as a privilege escalation technique under the T1059.007 sub-technique for "Command and Scripting Interpreter: PowerShell" when combined with other attack vectors. Organizations should implement immediate mitigations including input validation, proper file access controls, and restricting file system permissions for web applications. The most effective remediation involves implementing proper parameter validation, using allowlists for acceptable file paths, and ensuring that web applications do not permit arbitrary file access operations. Additionally, system administrators should consider implementing web application firewalls and monitoring for suspicious file access patterns to detect potential exploitation attempts.