Cisco IOS SSHv2 RSA-Based User Authentication Bypass (CSCus73013)

high Nessus Plugin ID 86249


The remote device is missing a vendor-supplied security patch.


The remote Cisco IOS device is missing a vendor-supplied security patch, and is configured for SSHv2 RSA-based user authentication. It is, therefore, affected by a flaw in the SSHv2 protocol implementation of the public key authentication method. An unauthenticated, remote attacker can exploit this, via a crafted private key, to bypass authentication mechanisms. In order to exploit this vulnerability an attacker must know a valid username configured for RSA-based user authentication and the public key configured for that user.


Upgrade to the relevant fixed version referenced in Cisco bug ID CSCus73013.

See Also

Plugin Details

Severity: High

ID: 86249

File Name: cisco-sa-20150923-sshpk-ios.nasl

Version: 1.11

Type: combined

Family: CISCO

Published: 10/2/2015

Updated: 12/1/2020

Risk Information


Risk Factor: Medium

Score: 5.9


Risk Factor: High

Base Score: 9.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2015-6280

Vulnerability Information

CPE: cpe:/o:cisco:ios

Required KB Items: Host/Cisco/IOS/Version

Patch Publication Date: 9/23/2015

Vulnerability Publication Date: 9/23/2015

Reference Information

CVE: CVE-2015-6280

CISCO-SA: cisco-sa-20150923-sshpk