CVE-1999-0174 in Communicator
Summary
by MITRE
the view-source cgi program allows remote attackers to read arbitrary files via a .. (dot dot) attack.
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Analysis
by VulDB Data Team • 12/26/2024
The vulnerability described in CVE-1999-0174 represents a classic directory traversal flaw in the view-source cgi program that was prevalent in early web server implementations. This weakness stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data before processing file requests. The vulnerability allows remote attackers to access files outside the intended directory structure by exploiting the .. (dot dot) sequence commonly used in unix-like file systems to navigate up one directory level. When the view-source cgi program processes a request containing such traversal sequences, it does not properly validate the requested file path, enabling attackers to bypass normal access controls and retrieve arbitrary files from the server's file system.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious request that includes directory traversal sequences in the file path parameter. The view-source cgi program, lacking proper path validation, processes these sequences literally and attempts to open files at locations specified by the attacker. This flaw directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as directory traversal or path traversal attacks. The vulnerability exists at the application level where the cgi program fails to implement proper input sanitization and path validation mechanisms, allowing attackers to manipulate file access patterns through carefully crafted requests.
The operational impact of this vulnerability is severe and multifaceted across multiple attack vectors and potential damage scenarios. Attackers can leverage this weakness to access sensitive system files such as configuration files, password databases, application source code, and other confidential information that should remain protected. The vulnerability enables unauthorized data exfiltration, potentially exposing credentials, system configurations, and business-critical information. From an attacker's perspective, this represents a low-effort, high-impact method of information gathering that can provide significant intelligence for further exploitation. The vulnerability can be exploited through various means including web browser interfaces, automated scanning tools, and manual exploitation techniques, making it particularly dangerous in environments where web servers are accessible to unauthenticated users.
Mitigation strategies for this vulnerability require immediate implementation of proper input validation and path sanitization measures. The most effective approach involves implementing strict validation of all file path inputs to ensure they remain within the intended directory boundaries. This can be achieved through various methods including canonicalizing file paths, implementing whitelist validation for allowed file extensions, and using secure file access libraries that prevent directory traversal sequences from being processed. Organizations should also implement proper access controls and privilege separation to limit the impact of successful exploitation attempts. Additionally, regular security auditing of web applications and cgi programs should be conducted to identify similar vulnerabilities in other components of the system infrastructure. The remediation process should align with established security practices outlined in industry standards including the OWASP Top Ten and NIST cybersecurity guidelines for preventing path traversal attacks. Regular updates and patches to web server software, along with proper security configuration management, are essential to prevent exploitation of similar vulnerabilities that may exist in other components of the web application stack.