CVE-2000-0261 in KEN!
Summary
by MITRE
The AVM KEN! web server allows remote attackers to read arbitrary files via a .. (dot dot) attack.
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Analysis
by VulDB Data Team • 04/21/2026
The CVE-2000-0261 vulnerability represents a critical directory traversal flaw in the AVM KEN! web server implementation that enables remote attackers to access arbitrary files on the affected system. This vulnerability stems from inadequate input validation within the web server's file handling mechanisms, specifically failing to properly sanitize user-supplied paths that contain directory traversal sequences. The flaw allows attackers to exploit the server's inability to distinguish between legitimate file requests and maliciously crafted paths containing double dot sequences that navigate upward through the directory structure. The vulnerability directly impacts the web server's security model by undermining the intended file system access controls and potentially exposing sensitive system files, configuration data, and user information to unauthorized access. This issue falls under the CWE-22 category of Improper Limitation of a Pathname to a Restricted Directory, which is classified as a path traversal vulnerability within the Common Weakness Enumeration framework. The attack vector leverages the standard HTTP protocol to send malicious requests containing sequences such as "../" that allow navigation through the file system hierarchy beyond the intended web root directory.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with the capability to access critical system files including but not limited to configuration files, database files, user credentials, and application source code. The potential for data breach increases significantly when considering that the vulnerability allows for arbitrary file reading without authentication requirements, making it particularly dangerous in environments where the web server hosts sensitive information. Attackers can exploit this flaw to retrieve system configuration files that may contain database connection strings, administrative credentials, or other sensitive data that could facilitate further compromise of the affected system. The vulnerability also poses risks to the integrity of the web server's operational environment, as the ability to read arbitrary files could enable attackers to identify system vulnerabilities, gather intelligence for subsequent attacks, or even attempt to upload malicious content if additional flaws exist within the server's file handling capabilities. This vulnerability directly relates to the ATT&CK technique T1083 (File and Directory Discovery) and T1566 (Phishing with Malicious Attachment) within the enterprise attack framework, as it provides the foundational access required for more sophisticated reconnaissance and exploitation activities.
Mitigation strategies for CVE-2000-0261 should focus on implementing proper input validation and sanitization mechanisms within the web server's file handling processes. The most effective approach involves implementing strict path validation that prevents traversal sequences from being processed by the web server, ensuring that all file access requests are properly validated against a predetermined whitelist of acceptable paths. System administrators should immediately apply vendor patches or upgrades that address this specific vulnerability, as the AVM KEN! web server is no longer actively supported and likely lacks current security updates. Additional protective measures include implementing web application firewalls that can detect and block directory traversal attempts, configuring the web server to operate with minimal privileges, and establishing proper access controls that limit the information accessible through the web interface. Organizations should also conduct comprehensive security assessments to identify other potential path traversal vulnerabilities within their web applications and implement secure coding practices that prevent similar issues from occurring in custom web applications. The vulnerability highlights the importance of following secure coding guidelines such as those outlined in the OWASP Top Ten and ISO/IEC 27001 security standards, which emphasize the need for proper input validation and output encoding to prevent various forms of injection attacks including directory traversal. Network segmentation and monitoring solutions should be deployed to detect and alert on suspicious file access patterns that may indicate exploitation attempts against this or similar vulnerabilities.