Microsoft Windows Privilege Escalation Vulnerability (CVE-2002-0367)
Published In CISA KEV since Sources: CVE.org
What is affected, what to do
smss.exe debugging subsystem in Windows NT and Windows 2000 does not properly authenticate programs that connect to other programs, which allows local users to gain administrator or SYSTEM privileges by duplicating a handle to a privileged process, as demonstrated by DebPloit.
The vulnerability is being actively exploited; treat it as a priority. The available sources name no fixed version. Check the vendor guidance in the references below. Immediate actions, mitigation and detection rules are in the runbook below.
- Affected
- Microsoft Windows NT
eq 4.0..4.0
- Microsoft Windows NT
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Metrics
7.8
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
7.8
CVSS v3
Severity High on the scale from 0 to 10.
Source: CVE.org
4.9 %
EPSS score
Moderate — model estimates 1-10% exploitation likelihood.
Source: FIRST EPSS, percentile 92.1
Show all metrics
- Severity
- Critical
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 206.87 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- actively exploited
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 7.8 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 7.8
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 4.9 %
- Moderate — model estimates 1-10% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 92.1
- Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- Actively exploited
- Published
In CISA KEV since
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- CISA assessment (SSVC)
- Exploitation: active · not automatable · Technical impact: total
- Source: CISA Vulnrichment, as of 7 February 2025
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-269
Response and mitigation
Why act now?
Prioritisation rationale
This flaw affects only Windows NT 4.0 and Windows 2000. Any locally logged-on low-privileged user can take full control of the host without user interaction, and a public exploit (DebPloit) has circulated for more than two decades. Its KEV listing reflects that attackers who gain an initial foothold reliably use such legacy holdovers to escalate privileges. Exploitation likelihood is clearly elevated relative to most CVEs, and CISA does not flag known ransomware use. If you have no such systems, a documented inventory check is enough to close the ticket. Where these hosts still run in OT, building-management or medical environments at critical-infrastructure operators, the risk is high, because no vendor support exists and isolation followed by replacement is the only durable remedy.
Runbook step 1
Immediate response (0-24 h)
- Inventory every Windows NT 4.0 and Windows 2000 host: Query AD on
operatingSystem(e.g.Get-ADComputer -Filter 'OperatingSystem -like "Windows 2000*" -or OperatingSystem -like "Windows NT*"' -Properties OperatingSystem,LastLogonDate). Supplement this with active and passive discovery (Nmap OS fingerprinting, Zeeksmb/ntlmlogs), because many legacy boxes in OT, lab and medical networks are not domain-joined. - Confirm vendor status: Both operating systems have been end-of-life for years. Microsoft shipped a historical fix; the patch is available from the vendor — look up the exact version in the vendor advisory or the Microsoft Security Bulletin archive. Verify that it is installed on every host you find. No new fixes will be released.
- Isolate affected hosts at the network layer: Move them into a dedicated segment immediately. Allow inbound traffic only from defined jump hosts and block all outbound internet access. The flaw requires local access, so whatever grants a session on the host (Terminal Services TCP 3389, SMB TCP 139/445, remote-admin tools) is the real attack surface.
- Restrict interactive logon: Enumerate every local and domain account that holds "Log on locally" or "Allow logon through Terminal Services". Disable accounts that are not needed and reset passwords for the rest, including local Administrator and service accounts. Any local user can reach SYSTEM through this flaw.
- Start a compromise assessment: On each legacy host, review the local Administrators group and user accounts for unknown entries. Sweep user profiles and
%TEMP%for unfamiliar executables.
- Inventory every Windows NT 4.0 and Windows 2000 host: Query AD on
Runbook step 2
Mitigation layers
- Network segmentation (IEC 62443 zones/conduits): Place legacy systems in their own zone behind a default-deny firewall. Permit only explicitly approved ports to named peers (PLCs, historians). Do not extend domain trust from production AD forests, so that local privilege escalation does not turn into credential theft across the estate.
- Access control / IAM: Allow interactive access only through hardened jump hosts with MFA and session recording. Never log on to these hosts with privileged domain accounts, because cached credentials (LSA secrets, SAM) are harvestable once an attacker holds SYSTEM. Use unique per-host local accounts instead.
- Application allow-listing / hardening: Where possible, deploy allow-listing products that still support legacy platforms; many OT vendors offer certified options. Block execution from user profiles, removable media and network shares, and disable USB mass storage physically or by policy.
- Physical security: The vector is local, so lock down console access to HMIs and operator stations with locked cabinets, kiosk mode, a BIOS password and a fixed boot order.
- Migration as the real fix: Document a dated replacement or virtualisation plan for every legacy host. Until it is complete, obtain formal risk acceptance from senior management, as required under NIS2 governance obligations and ISO 27001 A.5.9/A.8.8.
Runbook step 3
Detection rules
- Windows Security log (legacy event IDs): Enable "Audit process tracking" in the local security policy. Correlate Event ID 592 (new process) spawned under a user context with subsequent processes running as
NT AUTHORITY\SYSTEM. Sysmon does not support these platforms, so forward logs via an agentless collector or syslog forwarder. - Post-escalation account changes: Alert on Event ID 624 (user account created) and 636 (member added to local group) on legacy hosts. SPL sketch:
index=wineventlog host IN (legacy_hosts) EventCode IN (624,636) | stats count by host, user, Target_Account_Name. - Audit tampering: Treat Event ID 612 (audit policy changed) and 517 (security log cleared) on legacy hosts as critical. Attackers commonly wipe their tracks after gaining SYSTEM.
- Network telemetry (Zeek/Suricata): Flag new or unusual flows leaving the legacy segment, especially SMB to other hosts, outbound RDP, or any internet egress. Compare Zeek
conn.logagainst a baseline of approved communication pairs. - Interactive logons: Alert on Event ID 528 with Logon Type 2 (interactive) or 10 (remote interactive) when it occurs outside maintenance windows or comes from unapproved source hosts.
- Windows Security log (legacy event IDs): Enable "Audit process tracking" in the local security policy. Correlate Event ID 592 (new process) spawned under a user context with subsequent processes running as
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
smss.exe debugging subsystem in Windows NT and Windows 2000 does not properly authenticate programs that connect to other programs, which allows local users to gain administrator or SYSTEM privileges by duplicating a handle to a privileged process, as demonstrated by DebPloit.
Source: CISA KEV Catalog, NVD (NIST), cvelistv5
Vendors and products
Affected operating systems
| Windows | microsoft | windows_2000 | — |
| Windows | microsoft | windows_nt | 4.0 |
Weakness classes (CWE)
CWE-269Improper Privilege Management
Class
The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.
Entry at MITRE CWE-269
Public exploit references
Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.
| CISA KEV Catalog | CISA Known Exploited Vulnerability (opens in a new tab)cisa.gov | actively exploited |
References & sources
- securityfocus.com20020326 Re: DebPloit (exploit)Mailing list, x_refsource_BUGTRAQ
- marc.info20020314 DebPloit (exploit)Mailing list, x_refsource_NTBUGTRAQ
- securityfocus.com4287Vulnerability database, x_refsource_BID
- docs.microsoft.comMS02-024Vendor advisory, x_refsource_MS
- securityfocus.com20020327 Local Security Vulnerability in Windows NT and Windows 2000Mailing list, x_refsource_BUGTRAQ
- oval.cisecurity.orgoval:org.mitre.oval:def:76Vulnerability database, signature, x_refsource_OVAL
- securityfocus.com20020314 Fwd: DebPloit (exploit)Mailing list, x_refsource_BUGTRAQ
- iss.netwin-debug-duplicate-handles(8462)Vulnerability database, x_refsource_XF
- oval.cisecurity.orgoval:org.mitre.oval:def:158Vulnerability database, signature, x_refsource_OVAL
- cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2002-0367government-resource
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