Microsoft Windows NT 4.0 TCP Sequence Number authentication spoofing

CVSS Meta Temp Score
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CTI Interest Score
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5.1$0-$5k0.00

Summaryinfo

A vulnerability has been found in Microsoft Windows NT 4.0 and classified as critical. Affected by this vulnerability is an unknown functionality of the component TCP Sequence Number Handler. Performing a manipulation results in authentication spoofing. This vulnerability is known as CVE-1999-0077. Furthermore, an exploit is available. Due to its background and reception, this vulnerability has an historic impact. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Microsoft Windows NT 4.0 (Operating System). It has been classified as critical. This affects an unknown part of the component TCP Sequence Number Handler. The manipulation with an unknown input leads to a authentication spoofing vulnerability. CWE is classifying the issue as CWE-290. This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. This is going to have an impact on confidentiality.

The weakness was published 01/01/1995 (Website). It is possible to read the advisory at xforce.iss.net. This vulnerability is uniquely identified as CVE-1999-0077. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are unknown but a public exploit is available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 04/16/2026). Due to its background and reception, this vulnerability has a historic impact.

The exploit is shared for download at exploit-db.com. It is declared as highly functional. We expect the 0-day to have been worth approximately $25k-$100k. The vulnerability scanner Nessus provides a plugin with the ID 10443 (TCP/IP Predictable ISN (Initial Sequence Number) Generation Weakness), which helps to determine the existence of the flaw in a target environment. It is assigned to the family General and running in the context r. The commercial vulnerability scanner Qualys is able to test this issue with plugin 82005 (Predictable TCP Initial Sequence Numbers Vulnerability).

Upgrading to version XP or 2000 eliminates this vulnerability.

The vulnerability is also documented in the databases at X-Force (139), Exploit-DB (19522), Tenable (10443), SecurityFocus (BID 107†) and Secunia (SA8044†). Similar entries are available at VDB-14800, VDB-16127, VDB-16232 and VDB-16233. Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Authentication spoofing
CWE: CWE-290 / CWE-287
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Highly functional
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 10443
Nessus Name: TCP/IP Predictable ISN (Initial Sequence Number) Generation Weakness
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 802266
OpenVAS Name: TCP/IP Predictable TCP Initial Sequence Number Vulnerability
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Exploit-DB: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Windows XP/2000

Timelineinfo

01/01/1995 🔍
01/01/1995 +0 days 🔍
01/01/1995 +0 days 🔍
06/30/1998 +1276 days 🔍
12/24/2002 +1638 days 🔍
03/03/2003 +69 days 🔍
06/17/2014 +4124 days 🔍
04/16/2026 +4321 days 🔍

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: xforce.iss.net
Status: Confirmed

CVE: CVE-1999-0077 (🔍)
GCVE (CVE): GCVE-0-1999-0077
GCVE (VulDB): GCVE-100-13695
X-Force: 139 - TCP sequence prediction
SecurityFocus: 107 - Portmaster Predictable TCP Initial Sequence Number Vulnerability
Secunia: 8044
Vulnerability Center: 520 - Predictable TCP Sequence Number was Detected, Low

scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 06/17/2014 15:39
Updated: 04/16/2026 07:52
Changes: 06/17/2014 15:39 (78), 05/07/2019 09:44 (2), 11/23/2024 20:38 (18), 04/16/2026 07:52 (1)
Complete: 🔍
Cache ID: 216::103

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