CVE-2000-0097 is a vulnerability found in the WebHits ISAPI filter component of Microsoft Index Server version 2.0. This vulnerability, known as the "Malformed Hit-Highlighting Argument" vulnerability, allows remote attackers to read arbitrary files on the affected server without authentication. The issue arises because the WebHits ISAPI filter improperly processes certain crafted HTTP requests, enabling attackers to manipulate the hit-highlighting argument to access files outside the intended scope. This can lead to unauthorized disclosure of sensitive information stored on the server. The vulnerability is remotely exploitable over the network without requiring any user interaction or authentication, making it a significant risk for exposed systems. The CVSS v2 score assigned is 5.0 (medium severity), reflecting the potential confidentiality impact without affecting integrity or availability. Microsoft has released a patch to address this issue, detailed in security bulletin MS00-006. No known exploits have been reported in the wild, but the vulnerability remains critical for legacy systems still running Index Server 2.0, which is an outdated technology component primarily used in older Windows NT and Windows 2000 environments.

For European organizations, the impact of this vulnerability primarily concerns confidentiality breaches. Attackers exploiting this flaw can read arbitrary files, potentially exposing sensitive corporate data, configuration files, or user information. This could lead to further attacks such as credential theft, espionage, or compliance violations under regulations like GDPR. Although the vulnerability does not affect system integrity or availability directly, the unauthorized disclosure of information can have severe reputational and legal consequences. Organizations still operating legacy systems with Microsoft Index Server 2.0, particularly in sectors like government, finance, or critical infrastructure, may face increased risk. Since the vulnerability requires no authentication and can be exploited remotely, any publicly accessible web servers running this component are at risk. However, given the age of the product, most modern environments have likely migrated away from Index Server 2.0, reducing the overall exposure. Still, legacy or poorly maintained systems in European enterprises or public sector entities could be vulnerable if not patched.

1. Immediate application of the Microsoft patch MS00-006 is the primary mitigation step to remediate this vulnerability. 2. Conduct an inventory of all web servers to identify any running Microsoft Index Server 2.0 or related legacy components. 3. Disable or remove the WebHits ISAPI filter if it is not required for business operations. 4. Restrict network access to servers running legacy software by implementing firewall rules or network segmentation to limit exposure to the internet. 5. Monitor web server logs for unusual requests that may indicate attempts to exploit this vulnerability, such as malformed hit-highlighting arguments. 6. Plan and execute migration away from deprecated technologies like Index Server 2.0 to supported, modern web indexing and search solutions. 7. Implement regular vulnerability scanning and patch management processes to prevent similar issues in the future.