CVE-2000-0126 is a directory traversal vulnerability affecting Microsoft Internet Information Server (IIS) versions 3.0 and 4.0. The vulnerability arises from the Sample Internet Data Query (IDQ) scripts included with these IIS versions. These scripts improperly handle user input, allowing remote attackers to exploit a directory traversal (".." or dot-dot) attack to read arbitrary files on the web server. By manipulating the file path parameters in the IDQ scripts, an attacker can traverse out of the intended directory and access sensitive files anywhere on the server's filesystem that the IIS process has read permissions for. This vulnerability does not require authentication and can be exploited remotely over the network. The impact is limited to confidentiality, as attackers can read files but cannot modify them or disrupt service availability. The CVSS score is 5.0 (medium severity), reflecting the ease of exploitation (network accessible, no authentication) but limited impact scope (read-only access). No patches are available for this vulnerability, likely due to the age of the affected IIS versions, which are now obsolete and unsupported. There are no known exploits in the wild documented for this vulnerability, but the attack vector is straightforward and well-understood in the context of directory traversal flaws. Organizations still running IIS 3.0 or 4.0 with the sample IDQ scripts enabled are at risk of sensitive data disclosure through this vulnerability.

For European organizations, the primary impact of CVE-2000-0126 is unauthorized disclosure of sensitive information hosted on IIS 3.0 or 4.0 servers. Although these IIS versions are very old and largely replaced by newer versions, legacy systems may still exist in some environments, especially in industrial, governmental, or specialized sectors where legacy applications persist. An attacker exploiting this vulnerability could gain access to configuration files, source code, or other sensitive data, potentially leading to further attacks or data breaches. The confidentiality breach could expose personal data protected under GDPR, leading to regulatory and reputational consequences. However, the vulnerability does not allow modification or disruption of services, limiting its impact to information disclosure. Given the lack of patches, organizations relying on these IIS versions face a persistent risk unless mitigated by other controls or migration.

Since no official patches are available for IIS 3.0 and 4.0, European organizations should prioritize the following mitigations: 1) Immediate removal or disabling of the Sample Internet Data Query (IDQ) scripts from the IIS server to eliminate the vulnerable code path. 2) Restrict access to the IIS server by implementing network-level controls such as firewalls or VPNs to limit exposure to trusted users only. 3) Employ web application firewalls (WAFs) or intrusion detection/prevention systems (IDS/IPS) configured to detect and block directory traversal attempts targeting IDQ scripts. 4) Conduct thorough audits to identify any legacy IIS 3.0 or 4.0 servers and plan for urgent migration to supported IIS versions with active security updates. 5) Implement strict file system permissions to minimize the files accessible by the IIS process, reducing the potential data exposure if exploited. 6) Monitor server logs for suspicious requests containing directory traversal patterns to detect potential exploitation attempts early.