CVE-2002-0275 in Falcon Web Server
Summary
by MITRE
Falcon web server 2.0.0.1020 and earlier allows remote attackers to bypass authentication and read restricted files via an extra / (slash) in the requested URL.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 09/21/2025
The vulnerability identified as CVE-2002-0275 affects the Falcon web server version 2.0.0.1020 and earlier, presenting a critical security flaw that enables remote attackers to bypass authentication mechanisms and access restricted files through a simple manipulation of the requested URL. This issue represents a classic path traversal vulnerability that exploits improper input validation in the web server's URL parsing logic. The flaw specifically occurs when an attacker appends an additional forward slash character to the requested URL, which allows the server to interpret the request in a manner that circumvents normal access controls and file system restrictions. This vulnerability falls under the Common Weakness Enumeration category CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The technical implementation of this vulnerability exploits the web server's handling of URL normalization and path resolution. When the Falcon web server processes a request containing an extra slash character, the server's internal path resolution algorithm fails to properly canonicalize the requested path, allowing attackers to navigate beyond the intended document root directory. This occurs because the server does not adequately sanitize or validate the URL components before processing file system requests, creating a condition where maliciously crafted URLs can access files outside the designated web root. The vulnerability demonstrates a fundamental flaw in the server's input validation and path handling mechanisms, where the system fails to properly resolve relative paths and normalize URL components before attempting file access operations.
The operational impact of this vulnerability is severe and far-reaching, as it provides attackers with unrestricted access to sensitive files and directories on the server that should normally be protected from public access. Remote attackers can leverage this flaw to read configuration files, source code, database files, and other sensitive data that may contain authentication credentials, system information, or proprietary business data. The vulnerability essentially undermines the entire authentication framework of the web server, as it allows unauthorized access regardless of user permissions or access control lists. This type of vulnerability is particularly dangerous in production environments where web servers host critical applications and data, as it can lead to complete system compromise, data exfiltration, and potential lateral movement within network infrastructure. The attack vector is simple and effective, requiring minimal technical expertise to exploit, making it a preferred target for both automated scanning tools and determined attackers.
Mitigation strategies for this vulnerability must address both the immediate security gap and prevent similar issues in future implementations. The most effective immediate solution involves updating the Falcon web server to a patched version that properly handles URL normalization and path validation. System administrators should implement comprehensive input validation that sanitizes all URL components and ensures proper path canonicalization before file system operations are performed. Additionally, organizations should deploy web application firewalls and intrusion detection systems that can identify and block suspicious URL patterns containing excessive path separators. The implementation of proper access controls and least privilege principles should be enforced, ensuring that even if path traversal attacks succeed, the damage remains limited. From a defensive perspective, this vulnerability highlights the importance of following secure coding practices and implementing proper input validation, as recommended by the ATT&CK framework under the technique of T1059.007 for command and scripting interpreter. Organizations should also conduct regular security assessments and penetration testing to identify similar vulnerabilities in their web server configurations and applications.