CVE-2004-1133
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 · uneditedMultiple cross-site scripting (XSS) vulnerabilities in Microsoft W3Who ISAPI (w3who.dll) allow remote attackers to inject arbitrary HTML and web script via (1) HTTP headers such as "Connection" or (2) invalid parameters whose values are echoed in the resulting error message.
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 · moderate confidenceMicrosoft W3Who ISAPI extension (w3who.dll) fails to sanitize user input in HTTP headers (such as Connection) and invalid parameter values before reflecting them in error messages, allowing remote attackers to inject arbitrary HTML or JavaScript via cross-site scripting.
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 dataall versionsCVSS 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
- M
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:M/Au:N/C:P/I:P/A:P
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 checksWork through these to decide whether this CVE applies to you.
-
Verify if w3who.dll exists on the serverSearch for the file w3who.dll in the web root directories and IIS script paths (typically C:\Inetpub\, C:\Windows\System32\inetsrv\, or application bin directories). Use file system search or inspect known deployment locations.Affected if The file exists on the server, indicating the vulnerable component is present.
-
Check if w3who.dll is registered as an ISAPI extension in IISOpen IIS Manager, select the server or website, go to ISAPI Filters tab, or use the command 'appcmd list config' to inspect the ISAPI and CGI Restrictions configuration. Look for entries referencing w3who.dll.Affected if The extension is registered and enabled in IIS, making it reachable over HTTP.
-
Confirm the ISAPI extension is mapped to a URL pathCheck IIS Handler Mappings or URL Authorization settings to see if w3who.dll is mapped to a virtual path (commonly /w3who.dll or similar). Attempt a basic HTTP request to the suspected path if known.Affected if The extension is mapped to a URL that is accessible remotely, allowing attackers to send malicious requests.
-
Test for XSS via HTTP headersSend an HTTP request to the w3who.dll endpoint with a crafted Connection header containing XSS payload (e.g., <script>alert(1)</script>), and observe whether the value is reflected unsanitized in the response.Affected if The response reflects the header value without encoding or sanitization, confirming the vulnerability is exploitable.
The server is affected if w3who.dll is present and the ISAPI extension is enabled and accessible, as all versions contain the XSS flaw in header reflection.
Generated from the published advisory. Verify against your own configuration.
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 dataRemove the w3who.dll ISAPI extension if unused, or implement input validation/sanitization on all HTTP headers and parameters before reflecting them in responses. Consider deploying a WAF rule to filter XSS payloads until permanent remediation.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2004-1133 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2004-1133 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data