CVE-2002-1238 in Simple Web Server
Summary
by MITRE
Peter Sandvik s Simple Web Server 0.5.1 and earlier allows remote attackers to bypass access restrictions for files via an HTTP request with a sequence of multiple / (slash) characters such as http://www.example.com///file/.
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Analysis
by VulDB Data Team • 09/07/2025
The vulnerability identified as CVE-2002-1238 affects Peter Sandvik's Simple Web Server version 0.5.1 and earlier, representing a significant security flaw in web server implementations that has persisted for over two decades. This issue stems from inadequate input validation and path resolution mechanisms within the web server software, allowing malicious actors to exploit a fundamental weakness in how the server processes Uniform Resource Identifiers. The vulnerability specifically targets the server's handling of URL paths that contain multiple consecutive forward slash characters, creating a pathway for unauthorized access to restricted files and directories. This type of flaw demonstrates the critical importance of proper path normalization and access control enforcement in web server implementations, as it directly undermines the security model that protects sensitive resources from unauthorized access.
The technical implementation of this vulnerability occurs when a remote attacker crafts an HTTP request containing multiple consecutive slash characters in the URL path. When the Simple Web Server processes such a request, it fails to properly normalize the path structure, allowing the server to interpret the multiple slashes as a valid path traversal mechanism. This weakness enables attackers to bypass access controls that would normally prevent access to protected files, as the server's path resolution logic does not adequately sanitize or canonicalize the input. The flaw operates at the application layer of the network stack and represents a classic example of improper input validation, which is categorized under CWE-20 in the Common Weakness Enumeration catalog. The vulnerability essentially allows an attacker to perform a path traversal attack by manipulating the URL structure to access files that should be protected by access restrictions.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it provides attackers with the capability to potentially discover and retrieve sensitive information from the web server's file system. An attacker could exploit this weakness to access configuration files, source code, database files, or other sensitive resources that should remain protected from public access. The vulnerability affects the server's ability to enforce proper access controls, potentially leading to complete system compromise if sensitive files containing authentication credentials, database connection strings, or other critical information are accessible. This type of vulnerability is particularly dangerous because it can be exploited using simple HTTP requests without requiring complex attack vectors or specialized tools, making it accessible to attackers with minimal technical expertise. The impact aligns with ATT&CK technique T1213, which describes the exploitation of software vulnerabilities to gain access to information and resources within systems.
Mitigation strategies for CVE-2002-1238 should focus on implementing proper path normalization and input validation within the web server configuration. Organizations should ensure that all web server implementations properly canonicalize file paths and reject or normalize requests containing multiple consecutive slash characters. The most effective immediate solution involves updating to a newer version of the Simple Web Server that addresses this vulnerability, as version 0.5.1 and earlier are known to contain this flaw. Additionally, implementing proper access control mechanisms, including the use of web application firewalls and proper URL filtering rules, can help prevent exploitation attempts. Security configurations should include path validation rules that normalize all incoming URLs to ensure consistent path resolution regardless of input formatting. Organizations should also consider implementing monitoring and logging mechanisms to detect unusual access patterns that may indicate exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date software and implementing defense-in-depth strategies that include multiple layers of access control and input validation to prevent similar issues from compromising system security.