CVE-2000-0404 is a vulnerability in the CIFS (Common Internet File System) Computer Browser service, specifically affecting Microsoft Terminal Server version 4.0. The vulnerability arises because the Computer Browser service accepts ResetBrowser frames from remote attackers without sufficient validation. By sending a crafted ResetBrowser frame to the Master Browser, an attacker can disrupt the browser election process or force the Master Browser to reset, causing a denial of service (DoS) condition. This results in the temporary loss of network browsing functionality, where clients may be unable to locate or browse shared resources on the network. The vulnerability does not impact confidentiality or integrity but directly affects availability. The CVSS v2 score is 5.0 (medium severity), with an attack vector of network (remote), low attack complexity, no authentication required, and no impact on confidentiality or integrity, only availability. A patch addressing this vulnerability was released by Microsoft in May 2000 (MS00-036). There are no known exploits in the wild reported for this vulnerability, likely due to its age and the availability of patches. However, unpatched legacy systems running Terminal Server 4.0 remain vulnerable to remote DoS attacks that could disrupt network resource discovery and access.

For European organizations, the primary impact of this vulnerability is the disruption of network browsing services on affected Windows Terminal Server 4.0 systems. This can lead to temporary denial of service conditions where users cannot browse shared network resources, potentially impacting productivity and access to critical files or applications hosted on the network. While the vulnerability does not allow data theft or system compromise, the loss of availability can affect business operations, especially in environments relying on legacy Windows Terminal Server infrastructure. Organizations with legacy systems in sectors such as manufacturing, government, or critical infrastructure may experience operational disruptions. Given the age of the vulnerability and the availability of patches, the impact is mostly limited to organizations that have not updated or migrated from outdated Microsoft Terminal Server versions.

1. Apply the official Microsoft patch MS00-036 immediately to all affected Terminal Server 4.0 systems to remediate the vulnerability. 2. Where possible, upgrade legacy Terminal Server 4.0 systems to supported versions of Windows Server to benefit from improved security and support. 3. Restrict network access to Terminal Server systems by implementing network segmentation and firewall rules to limit exposure to untrusted networks, reducing the attack surface. 4. Monitor network traffic for unusual ResetBrowser frame packets or abnormal Master Browser resets as an indicator of attempted exploitation. 5. Disable the Computer Browser service on systems where it is not required to minimize the attack surface. 6. Implement network access controls and intrusion detection systems capable of detecting anomalous SMB/CIFS traffic patterns related to browser service disruptions.