Index ServerApplication · Microsoft

CVE-2001-0500

HIGH · 10.0 CVSS v2.0 Published 2001-07-21
Fix available
A fix is available. Upgrade to after 6.0 or later.
See remediation →
100/100
Remediation priority · Urgent
High EPSS Public exploit Remotely reachable No privileges Zero-click Patch available

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
Buffer overflow in ISAPI extension (idq.dll) in Index Server 2.0 and Indexing Service 2000 in IIS 6.0 beta and earlier allows remote attackers to execute arbitrary commands via a long argument to Internet Data Administration (.ida) and Internet Data Query (.idq) files such as default.ida, as commonly exploited by Code Red.

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

A detailed technical summary for this CVE is being prepared.

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
Index ServerApplication
Affected:= 2.0
Indexing ServiceApplication
Affected:all versions
Internet Information ServerApplication
Affected:<= 6.0

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
Complete
Integrity
Complete
Availability
Complete

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

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.

dbcve · scoped
Upgrade available Upgrade to a release after 6.0
Vendor patch www.cert.org →
Recommended fix High confidence

IIS 6.0 on Windows Server 2003 with all security updates applied, or migrate to IIS 7.0/7.5 on Windows Server 2008/2008 R2

  1. Apply Microsoft Security Patch MS01-033 (or subsequent cumulative security updates for IIS)
  2. After patching, verify the idq.dll ISAPI extension is either removed or disabled in IIS Manager
  3. Navigate to IIS Manager > Web Service Extensions > restrict 'Indexing Service' and 'Internet Data Administration' extensions
  4. Alternatively, from command line: uninstall or rename idq.dll (typically in %systemroot%\system32\inetsrv)
  5. Verify remediation by attempting to access a .ida file (e.g., default.ida?N=0) - it should return a 404 error, not execute code
  6. Ensure all subsequent cumulative security patches for IIS are applied
Caveat If idq.dll is required for legacy applications, test thoroughly before removal; consider migrating to alternative query mechanisms supported by newer IIS versions

Generated from the published advisory — verify against the referenced sources before acting.

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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-2001-0500 in production — separate from our analysis above.

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