[SANOG] Cisco Security Advisory: Cisco IOS and IOS XE Software SSH Version 2 RSA-Based User Authentication Bypass Vulnerability
Cisco Systems Product Security Incident Response Team
psirt at cisco.com
Wed Sep 23 16:08:26 UTC 2015
-----BEGIN PGP SIGNED MESSAGE-----
Cisco IOS and IOS XE Software SSH Version 2 RSA-Based User Authentication Bypass Vulnerability
Advisory ID: cisco-sa-20150923-sshpk
For Public Release 2015 September 23 16:00 UTC (GMT)
A vulnerability in the SSH version 2 (SSHv2) protocol implementation of Cisco IOS and IOS XE Software could allow an unauthenticated, remote attacker to bypass user authentication.
Successful exploitation could allow the attacker to log in with the privileges of the user or the privileges configured for the Virtual Teletype (VTY) line. Depending on the configuration of the user and of the vty line, the attacker may obtain administrative privileges on the system. The attacker cannot use this vulnerability to elevate privileges.
The attacker must know a valid username configured for RSA-based user authentication and the public key configured for that user to exploit this vulnerability. This vulnerability affects only devices configured for public key authentication method, also known as RSA-based user authentication feature.
Cisco has released software updates that address this vulnerability.
Workarounds for this vulnerability are not available; however administrators could temporarily disable RSA-based user authentication to avoid exploitation.
This advisory is available at the following link:
Note: The September 23, 2015, release of the Cisco IOS and IOS XE Software Security Advisory bundled publication includes three Cisco Security Advisories. All the advisories address vulnerabilities in Cisco IOS Software and Cisco IOS XE Software. Individual publication links are in Cisco Event Response: September 2015 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication at the following link:
-----BEGIN PGP SIGNATURE-----
Comment: GPGTools - http://gpgtools.org
-----END PGP SIGNATURE-----
More information about the sanog