Cisco IOS up to 12.3 SSHv2 TACACS+ improper authentication

CVSS Meta Temp Score
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CTI Interest Score
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6.7$0-$5k0.00

A vulnerability has been found in Cisco IOS up to 12.3 (Router Operating System) and classified as critical. This vulnerability affects some unknown processing of the component SSHv2 TACACS+ Handler. The manipulation with an unknown input leads to a improper authentication vulnerability. The CWE definition for the vulnerability is CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. As an impact it is known to affect availability. CVE summarizes:

Secure Shell (SSH) 2 in Cisco IOS 12.0 through 12.3 allows remote attackers to cause a denial of service (device reload) (1) via a username that contains a domain name when using a TACACS+ server to authenticate, (2) when a new SSH session is in the login phase and a currently logged in user issues a send command, or (3) when IOS is logging messages and an SSH session is terminated while the server is sending data.

The bug was discovered 04/06/2005. The weakness was released 04/06/2005 with Cisco (Website). The advisory is shared for download at cisco.com. This vulnerability was named CVE-2005-1020 since 04/10/2005. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are unknown but a public exploit is available.

After immediately, there has been an exploit disclosed. It is declared as proof-of-concept. As 0-day the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 17988 (Cisco IOS Secure Shell Server TACACS+ Multiple DoS (CSCed65778, CSCed65285)), 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 43098 (Cisco IOS Secure Shell Server Memory Leak Denial of Service Vulnerability (cisco-sa-20050406-ssh)).

Applying a patch is able to eliminate this problem. The bugfix is ready for download at cisco.com. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at X-Force (19987) and Tenable (17988). Entry connected to this vulnerability is available at 24799.

Productinfo

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Support

  • end of life (old version)

CPE 2.3info

CPE 2.2info

CVSSv4info

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CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 6.7

VulDB Base Score: 7.5
VulDB Temp Score: 6.7
VulDB Vector: 🔍
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CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
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Exploitinginfo

Class: Improper authentication
CWE: CWE-287
CAPEC: 🔍
ATT&CK: 🔍

Local: No
Remote: Yes

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

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Current Price Estimation: 🔍

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Nessus ID: 17988
Nessus Name: Cisco IOS Secure Shell Server TACACS+ Multiple DoS (CSCed65778, CSCed65285)
Nessus File: 🔍
Nessus Risk: 🔍
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Threat Intelligenceinfo

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Countermeasuresinfo

Recommended: Patch
Status: 🔍

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Patch: cisco.com

Timelineinfo

04/06/2005 🔍
04/06/2005 +0 days 🔍
04/06/2005 +0 days 🔍
04/06/2005 +0 days 🔍
04/06/2005 +0 days 🔍
04/06/2005 +0 days 🔍
04/06/2005 +0 days 🔍
04/06/2005 +0 days 🔍
04/07/2005 +1 days 🔍
04/10/2005 +2 days 🔍
04/12/2005 +2 days 🔍
04/12/2005 +0 days 🔍
05/02/2005 +20 days 🔍
07/02/2019 +5174 days 🔍

Sourcesinfo

Vendor: cisco.com

Advisory: cisco.com
Researcher: http://www.cisco.com
Organization: Cisco
Status: Not defined

CVE: CVE-2005-1020 (🔍)
OVAL: 🔍

X-Force: 19987 - Cisco IOS SSHv2 TACACS+ command authentication denial of service, Medium Risk
SecurityTracker: 1013655
Vulnerability Center: 7567 - [cisco-sa-20050406-ssh] DoS in Cisco IOS SSH Server, Medium
SecurityFocus: 13043 - Cisco IOS Secure Shell Server V2 Remote Denial Of Service Vulnerability
Secunia: 14854 - Cisco IOS Secure Shell Server Denial of Service Vulnerabilities, Less Critical
OSVDB: 15303 - Cisco IOS Secure Shell Server TACACS+ Authentication Failure Memory Exhaustion DoS

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

Entryinfo

Created: 04/12/2005 14:58
Updated: 07/02/2019 09:39
Changes: 04/12/2005 14:58 (93), 07/02/2019 09:39 (5)
Complete: 🔍

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