CVE-2000-0413 is a medium-severity vulnerability affecting the shtml.exe program within the FrontPage extensions package for Microsoft Internet Information Services (IIS) versions 4.0 and 5.0. The vulnerability arises because shtml.exe improperly handles requests for non-existent files with certain extensions (HTML, HTM, ASP, and SHTML). When a remote attacker requests a file that does not exist, the server generates an error message that inadvertently discloses the physical file system path of the requested resource. This information disclosure flaw does not allow direct modification or disruption of data or services but reveals sensitive internal directory structures to unauthenticated remote attackers over the network. The vulnerability has a CVSS v2 base score of 5.0, reflecting its medium severity, with an attack vector of network (AV:N), low attack complexity (AC:L), no authentication required (Au:N), partial confidentiality impact (C:P), and no impact on integrity or availability (I:N/A:N). No patches or fixes are available for this vulnerability, and there are no known exploits in the wild. The vulnerability is limited to legacy Microsoft IIS versions 4.0 and 5.0 with FrontPage extensions installed, which are largely obsolete but may still be present in some legacy or unmaintained environments.

For European organizations, the primary impact of CVE-2000-0413 is the unintended disclosure of internal directory paths on web servers running IIS 4.0 or 5.0 with FrontPage extensions. This information disclosure can aid attackers in reconnaissance activities, enabling them to map the server's file system structure and potentially identify sensitive files or configuration locations. While this vulnerability alone does not allow direct compromise or data manipulation, it can be leveraged as a stepping stone for more targeted attacks, such as directory traversal, privilege escalation, or exploitation of other vulnerabilities that depend on knowledge of the server's file layout. Given that IIS 4.0 and 5.0 are outdated and unsupported, organizations still running these versions may also be vulnerable to numerous other critical security issues, compounding the risk. The impact is particularly relevant for organizations with legacy web infrastructure that has not been modernized or patched, including government agencies, educational institutions, and certain industrial sectors in Europe. The vulnerability does not affect newer IIS versions or other web server platforms, limiting its scope but still posing a risk where legacy systems remain in operation.

Since no official patch is available for CVE-2000-0413, European organizations should prioritize the following specific mitigation steps: 1) Upgrade or migrate legacy IIS 4.0 and 5.0 servers with FrontPage extensions to supported, modern versions of IIS or alternative web server platforms that do not contain this vulnerability. 2) If upgrading is not immediately feasible, disable or remove the FrontPage extensions package entirely to eliminate the vulnerable shtml.exe component. 3) Implement web server configuration changes to suppress detailed error messages that reveal physical paths, such as customizing error handling to return generic messages without path information. 4) Restrict external access to legacy web servers by placing them behind firewalls or VPNs, limiting exposure to untrusted networks. 5) Conduct thorough inventory and risk assessments to identify any remaining IIS 4.0/5.0 servers and prioritize their remediation. 6) Monitor web server logs for suspicious requests targeting non-existent files with the relevant extensions, which may indicate reconnaissance attempts exploiting this vulnerability. These targeted mitigations go beyond generic advice by focusing on legacy system identification, removal of vulnerable components, and error message hardening specific to this vulnerability.