Cisco Catalyst CatOS prior 8.3(2)GLX TCP Connection denial of service

CVSS Meta Temp Score
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CTI Interest Score
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5.3$0-$5k0.00

Summaryinfo

A vulnerability classified as critical has been found in Cisco Catalyst CatOS. The affected element is an unknown function of the component TCP Connection Handler. Performing a manipulation results in denial of service. This vulnerability is cataloged as CVE-2004-0551. It is possible to initiate the attack remotely. Furthermore, there is an exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Cisco Catalyst CatOS. It has been classified as critical. This affects some unknown processing of the component TCP Connection Handler. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. The summary by CVE is:

Cisco CatOS 5.x before 5.5(20) through 8.x before 8.2(2) and 8.3(2)GLX, as used in Catalyst switches, allows remote attackers to cause a denial of service (system crash and reload) by sending invalid packets instead of the final ACK portion of the three-way handshake to the (1) Telnet, (2) HTTP, or (3) SSH services, aka "TCP-ACK DoS attack."

The bug was discovered 06/09/2004. The weakness was shared 06/09/2004 with Cisco Systems Product Security Incident Response T (Website). It is possible to read the advisory at cisco.com. This vulnerability is uniquely identified as CVE-2004-0551 since 06/11/2004. 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 attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

After 1 days, there has been an exploit disclosed. It is declared as proof-of-concept. We expect the 0-day to have been worth approximately $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 12270 (Cisco CatOS TCP-ACK Remote DoS (CSCec42751, CSCed45576, CSCed48590)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family CISCO, running in the context l and relying on port 161. The commercial vulnerability scanner Qualys is able to test this issue with plugin 43059 (Cisco IOS CatOS TCP-ACK Denial of Service Vulnerability).

Upgrading to version 8.3(2)GLX eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at cisco.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at X-Force (16370), Tenable (12270), SecurityFocus (BID 10504†), OSVDB (6829†) and Secunia (SA11821†). Further details are available at heise.de. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.9
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.9
VulDB Temp Score: 5.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

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VulDB Base Score: 🔍
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NVD Base Score: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 12270
Nessus Name: Cisco CatOS TCP-ACK Remote DoS (CSCec42751, CSCed45576, CSCed48590)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍
Nessus Port: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍
Exploit Delay Time: 🔍

Upgrade: Catalyst CatOS 8.3(2)GLX
Patch: cisco.com

Timelineinfo

06/09/2004 🔍
06/09/2004 +0 days 🔍
06/09/2004 +0 days 🔍
06/09/2004 +0 days 🔍
06/09/2004 +0 days 🔍
06/10/2004 +1 days 🔍
06/10/2004 +0 days 🔍
06/10/2004 +0 days 🔍
06/11/2004 +0 days 🔍
06/11/2004 +0 days 🔍
06/13/2004 +2 days 🔍
08/06/2004 +54 days 🔍
07/12/2025 +7645 days 🔍

Sourcesinfo

Vendor: cisco.com

Advisory: cisco.com
Researcher: http://www.cisco.com
Organization: Cisco Systems Product Security Incident Response T
Status: Confirmed

CVE: CVE-2004-0551 (🔍)
GCVE (CVE): GCVE-0-2004-0551
GCVE (VulDB): GCVE-100-699
CERT: 🔍
X-Force: 16370 - Cisco Catalyst CatOS ACK denial of service, Medium Risk
SecurityFocus: 10504 - Cisco CatOS TCP-ACK Denial Of Service Vulnerability
Secunia: 11821 - Cisco CatOS TCP-ACK Denial of Service Vulnerability, Less Critical
OSVDB: 6829 - Cisco CatOS TCP-ACK Remote DoS
SecurityTracker: 1010444
SecuriTeam: securiteam.com
Vulnerability Center: 4490 - [cisco-sa-20040609-catos] DoS in Cisco CatOS via Improper TCP-ACK Handshake, Medium

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

Entryinfo

Created: 06/10/2004 14:12
Updated: 07/12/2025 19:58
Changes: 06/10/2004 14:12 (97), 06/28/2019 16:37 (1), 11/19/2024 18:38 (16), 07/12/2025 19:58 (2)
Complete: 🔍
Cache ID: 216:E39:103

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