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Internet Information ServerApplication · Microsoft

CVE-2005-2678

MEDIUM · 5.0 CVSS v2.0 Published 2005-08-23
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Microsoft IIS 5.1 and 6 allows remote attackers to spoof the SERVER_NAME variable to bypass security checks and conduct various attacks via a GET request with an http://localhost URI, which makes it appear as if the request is coming from localhost.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Microsoft IIS 5.1 and 6 contains a vulnerability where the SERVER_NAME server variable can be spoofed via a GET request containing 'http://localhost' in the URL, causing IIS to incorrectly interpret the request as originating from localhost. This allows attackers to bypass security checks that rely on SERVER_NAME for authentication or access control decisions.

MitigationApply Microsoft's MS05-025 security patch, or migrate from IIS 5.1/6 to a supported version (IIS 7.0+). Implement supplementary validation using X-Forwarded-For headers and additional server-side checks for hostname-based security logic.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Internet Information ServerApplication
Affected:= 6.0
Internet Information ServicesApplication
Affected:= 5.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Authentication
None
Confidentiality
Partial
Integrity
None
Availability
None

AV:N/AC:L/Au:N/C:P/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed IIS version
    Open Command Prompt and run: iisweb.vbs /query C:\WINDOWS\system32\inetsrv or check the Windows registry key HKLM\SYSTEM\CurrentControlSet\Services\W3SVC\Parameters\MajorVersion
    Affected if The version is 5.0, 5.1, or 6.0 (the versions listed in the affected products)
  2. Locate applications using SERVER_NAME for security
    Search web application source code for usages of Request.ServerVariables("SERVER_NAME") or equivalent API calls that perform hostname-based authentication or authorization logic
    Affected if Any application code relies on SERVER_NAME for access control decisions such as IP restrictions, hostname allowlists, or authentication bypass logic
  3. Identify URL-based security configurations in IIS
    Review IIS URL authorization rules and ISAPI filters that perform hostname validation using the SERVER_NAME variable, accessible via IIS Manager under URL Authorization or through the configuration files in C:\WINDOWS\system32\inetsrv\config
    Affected if URL authorization rules or custom ISAPI filters validate incoming requests based on the SERVER_NAME server variable
  4. Test for SERVER_NAME spoofing susceptibility
    Send a GET request to the application with a URL containing 'http://localhost' (for example: GET /somepath?test=http://localhost HTTP/1.1 with Host header set to the actual server name) and observe whether the SERVER_NAME server variable reports 'localhost' instead of the actual hostname
    Affected if The application responds as if the request originated from localhost, indicating the vulnerability is present

You are affected if you run IIS 5.0, 5.1, or 6.0 AND have any security logic (application code, URL rules, or ISAPI filters) that relies on the SERVER_NAME variable for authentication or access control decisions.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Microsoft's MS05-025 security patch, or migrate from IIS 5.1/6 to a supported version (IIS 7.0+). Implement supplementary validation using X-Forwarded-For headers and additional server-side checks for hostname-based security logic.

Fix this in Internet Information Server Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2005-2678 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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