CVE-2003-0661
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 · uneditedThe NetBT Name Service (NBNS) for NetBIOS in Windows NT 4.0, 2000, XP, and Server 2003 may include random memory in a response to a NBNS query, which could allow remote attackers to obtain sensitive information.
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 confidenceThe NetBIOS Name Service (NBNS) in Windows NT 4.0, 2000, XP, and Server 2003 includes uninitialized memory contents in responses to NBNS queries, allowing remote attackers to obtain potentially sensitive information from heap/stack memory via specially crafted requests to UDP port 137.
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 versions= enterprise= enterprise_64-bit= r2= standard= web= 4.0all 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
- 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 checksWork through these to decide whether this CVE applies to you.
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Identify Windows versionRun 'winver' from Start > Run, or use 'systeminfo' command in Command Prompt, or check the OS name and build number in System PropertiesAffected if The version matches Windows NT 4.0, Windows 2000 (any version), Windows XP (any version), or Windows Server 2003 (enterprise, enterprise_64-bit, r2, standard, or web editions)
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Verify NetBIOS over TCP/IP is enabledOpen Network Connections, right-click the active network adapter, select Properties > Internet Protocol (TCP/IP) > Properties > Advanced > WINS tab, or run 'nbtstat -n' to see local NetBIOS names registeredAffected if NetBIOS over TCP/IP is set to 'Enable' or 'Default' - the NBNS service is active and responding to queries on UDP port 137
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Confirm UDP port 137 is listeningRun 'netstat -an | findstr "137"' or use 'nbtstat -a <localIP>' to check if the system is bound to UDP port 137Affected if Port 137/UDP is shown as LISTENING or the system responds to nbtstat queries, indicating the NBNS service is exposed on the network
A system is affected if it runs a vulnerable Windows version (NT 4.0, 2000, XP, or Server 2003) AND has NetBIOS over TCP/IP enabled with UDP port 137 exposed, allowing remote attackers to send specially crafted NBNS queries to extract memory contents.
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 dataApply Microsoft security patches for this vulnerability. If patches are unavailable or NetBIOS naming is not required, disable NetBIOS over TCP/IP or block UDP port 137 at network boundaries.
- Consultation3.0 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 $2,880.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2003-0661 — 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-2003-0661 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
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- 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
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