CVE-2000-0261 is a directory traversal vulnerability affecting the AVM KEN! web server versions 1.3.10 and 1.4.30. This vulnerability allows remote attackers to read arbitrary files on the affected server by exploiting a '..' (dot dot) path traversal attack. Essentially, the web server fails to properly sanitize user-supplied input in URL paths, enabling attackers to navigate outside the intended web root directory and access sensitive files anywhere on the filesystem that the web server process has permission to read. The vulnerability requires no authentication and can be exploited remotely over the network. The CVSS score of 5.0 (medium severity) reflects that the attack vector is network-based, with low attack complexity, no authentication required, and impacts confidentiality only, without affecting integrity or availability. There is no patch available for this vulnerability, and no known exploits have been reported in the wild. Given the age of this vulnerability (published in 2000), it primarily affects legacy systems still running these specific versions of the AVM KEN! web server. The lack of a patch means organizations must rely on compensating controls or upgrade to newer, unaffected software versions if available.

For European organizations, the impact of this vulnerability primarily concerns confidentiality breaches. Attackers exploiting this flaw can read sensitive configuration files, password files, or other critical data stored on the server, potentially leading to further compromise or data leakage. While the vulnerability does not allow modification or denial of service, unauthorized disclosure of sensitive information can have serious consequences, including violation of GDPR requirements for data protection and privacy. Organizations in sectors such as government, finance, healthcare, and critical infrastructure that may still run legacy AVM KEN! web servers could face reputational damage, regulatory penalties, and operational risks if exploited. However, given the age and obscurity of the affected product, the overall risk is likely low unless legacy systems remain in active use without mitigation.

Since no official patch is available, European organizations should prioritize the following mitigations: 1) Identify and inventory any AVM KEN! web servers running affected versions (1.3.10 or 1.4.30) within their environment. 2) Immediately isolate or decommission these legacy servers to prevent exposure. 3) If continued use is necessary, implement strict network segmentation and firewall rules to restrict access to the web server only to trusted internal IPs. 4) Employ web application firewalls (WAFs) or intrusion prevention systems (IPS) capable of detecting and blocking directory traversal attempts, specifically '..' sequences in URL paths. 5) Conduct regular file integrity monitoring to detect unauthorized access or exfiltration attempts. 6) Consider migrating to modern, supported web server software that does not have this vulnerability. 7) Educate IT staff about the risks of legacy software and the importance of timely upgrades and patching.