Windows NtOperating system · Microsoft

CVE-1999-1579

MEDIUM · 5.0 CVSS v2.0 Published 2000-12-14
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
The Cenroll ActiveX control (xenroll.dll) for Terminal Server Editions of Windows NT 4.0 and Windows NT Server 4.0 before SP6 allows remote attackers to cause a denial of service (resource consumption) by creating a large number of arbitrary files on the target machine.

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 confidence

The Cenroll ActiveX control (xenroll.dll) in Windows NT 4.0 Terminal Server editions contains a vulnerability allowing remote attackers to cause denial of service by creating numerous arbitrary files on the target system, exhausting disk resources.

MitigationApply Windows NT Server 4.0 SP6 or later, or disable/remove the vulnerable xenroll.dll ActiveX control if the system cannot be patched. For legacy systems no longer under support, consider migration or network isolation.

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
Windows NtOperating system
Affected:= 4.0

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
None
Integrity
None
Availability
Partial

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

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

  1. Confirm Windows NT version
    Check system version by right-clicking 'My Computer', selecting 'Properties', or running 'winver.exe' from the command line. Look for 'Windows NT' and version 4.0.
    Affected if The system is running Windows NT 4.0 (any build)
  2. Verify Terminal Server edition
    Check if the system is a Terminal Server edition by reviewing the system properties or running 'winver' which displays the OS name including 'Terminal Server Edition' if applicable.
    Affected if The system is Windows NT 4.0 Terminal Server Edition
  3. Locate xenroll.dll
    Search for the file xenroll.dll on the system. Common paths include C:\Winnt\System32\ or C:\Windows\System\. Use Windows Explorer search or run 'dir /s xenroll.dll' from the root.
    Affected if The file xenroll.dll exists on the system
  4. Check if ActiveX controls are enabled
    In Internet Explorer, go to Tools > Internet Options > Security > Custom Level. Look for 'Run ActiveX controls and plugins' settings, or check for ActiveX control permissions in the Windows registry under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Zones.
    Affected if ActiveX controls are permitted to run (not disabled for all zones)
  5. Verify the vulnerable service is running
    Check if IIS or any web service that might serve pages hosting the ActiveX control is running. Open Services Control Panel or run 'net start' to list running services.
    Affected if Web services are running that could serve HTML pages containing the vulnerable ActiveX control

A system is affected if it is Windows NT 4.0 Terminal Server Edition with xenroll.dll present and ActiveX controls enabled, making it possible for remote attackers to trigger file creation via the vulnerable Cenroll control.

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 Windows NT Server 4.0 SP6 or later, or disable/remove the vulnerable xenroll.dll ActiveX control if the system cannot be patched. For legacy systems no longer under support, consider migration or network isolation.

Fix this in Windows Nt Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
36.0 hours of engineering $6,400
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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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-1999-1579 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
  • 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