Cisco Security Advisory
Cisco NX-OS Software-Based Products Authentication, Authorization, and Accounting Bypass Vulnerability
Critical
Advisory ID:
cisco-sa-20161005-nxaaa
First Published:
2016 October 5 16:00 GMT
Version 1.0:
Workarounds:
No workarounds available
Cisco Bug IDs:
CVSS Score:
Base 9.0,
Temporal 7.4Click Icon to Copy Verbose Score
AV:N/AC:L/Au:S/C:C/I:C/A:C/E:F/RL:OF/RC:C
AV:N/AC:L/Au:S/C:C/I:C/A:C/E:F/RL:OF/RC:C
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A vulnerability in the SSH subsystem of the Cisco Nexus family of products could allow an authenticated, remote attacker to bypass authentication, authorization, and accounting (AAA) restrictions.
The vulnerability is due to the improper processing of certain parameters that are passed to an affected device during the negotiation of an SSH connection. An attacker could exploit this vulnerability by authenticating to an affected device and passing a malicious value as part of the login procedure. A successful exploit could allow an attacker to bypass AAA restrictions and execute commands on the device command-line interface (CLI) that should be restricted to a different privileged user role.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20161005-nxaaa
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Vulnerable Products
The following Cisco products are vulnerable if they are running Cisco NX-OS System Software that is configured for AAA authentication and is accessible via SSH for IPv4 or IPv6.
- Multilayer Director Switches
- Nexus 1000V Series Switches
- Nexus 2000 Series Fabric Extenders
- Nexus 3000 Series Switches
- Nexus 3500 Platform Switches
- Nexus 4000 Series Switches
- Nexus 5000 Series Switches
- Nexus 5500 Platform Switches
- Nexus 5600 Platform Switches
- Nexus 6000 Series Switches
- Nexus 7000 Series Switches
- Nexus 7700 Series Switches
- Nexus 9000 Series Switches in NX-OS mode
Administrators can check the version of NX-OS Software running on their device by utilizing the show version command from the device CLI. The following example identifies the 6.2(14) release:
nxos-switch# show version
Cisco Nexus Operating System (NX-OS) Software
TAC support: http://www.cisco.com/tac
Documents:
http://www.cisco.com/en/US/products/ps9372/tsd_products_support_series_home.
html
Copyright (c) 2002-2015, Cisco Systems, Inc. All rights reserved.
The copyrights to certain works contained in this software are
owned by other third parties and used and distributed under
license. Certain components of this software are licensed under
the GNU General Public License (GPL) version 2.0 or the GNU
Lesser General Public License (LGPL) Version 2.1. A copy of each
such license is available at
http://www.opensource.org/licenses/gpl-2.0.php and
http://www.opensource.org/licenses/lgpl-2.1.php
Software
BIOS: version 2.12.0
kickstart: version 6.2(14)
system: version 6.2(14)
.
.
.Products Confirmed Not Vulnerable
The following products are not affected by this vulnerability:
- Nexus 9000 Series Switches in Application Centric Infrastructure (ACI) mode
- Unified Computing System (UCS) 6100 Series Fabric Interconnects
- Unified Computing System (UCS) 6200 Series Fabric Interconnects
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There are no workarounds that address this vulnerability.
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Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license: http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html.
Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
When considering software upgrades, customers are advised to consult the Cisco Security Advisories and Responses archive at http://www.cisco.com/go/psirt and review subsequent advisories to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to upgrade contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco Technical Assistance Center (TAC): http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html.
Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
Fixed Releases
Customers should upgrade to an appropriate release as indicated in the applicable table in this section. To help ensure a complete upgrade solution, consider that this advisory is part of a collection that includes the following advisories:
cisco-sa-20161005-bgp: Cisco NX-OS Border Gateway Protocol Denial of Service Vulnerability
cisco-sa-20161005-dhcp1: Cisco NX-OS Software Crafted DHCPv4 Packet Denial of Service Vulnerability
cisco-sa-20161005-dhcp2: Cisco NX-OS Software Malformed DHCPv4 Packet Denial of Service Vulnerability
cisco-sa-20161005-nxaaa: Cisco NX-OS Software-Based Products Authentication, Authorization, and Accounting Bypass Vulnerability
cisco-sa-20161005-otv: Cisco Nexus 7000 and 7700 Series Switches Overlay Transport Virtualization Buffer Overflow Vulnerability
In the following table, the left column lists major releases of Cisco NX-OS Software. The center column indicates whether a major release is affected by the vulnerability described in this advisory and the first minor release that includes the fix for this vulnerability. The right column indicates whether a major release is affected by all the vulnerabilities described in this collection of advisories and which release includes fixes for those vulnerabilities.
Cisco Nexus 1000 Series Switches : CSCuw79754
Cisco NX-OS Software Major Release - Nexus 1000V Series Switches First Fixed Release for This Vulnerability First Fixed Release for This Vulnerability All Vulnerabilities Described in the Collection of Advisories
Prior to 4.2 Affected; migrate to 5.2(1)SV3(1.10)
5.2(1)SV3(1.15) 5.2 5.2(1)SV3(1.10) 5.2(1)SV3(1.15)
Cisco Nexus 3000 and 3500 Series Switches : CSCum35502
Cisco NX-OS Software Major Release - Nexus 3000 Series Switches First Fixed Release for This Vulnerability First Fixed Release for This Vulnerability and All Vulnerabilities Described in the Collection of Advisories
Prior to 6.0 Affected; migrate to 6.0(2)U6(5a)
6.0(2)U6(7) 6.0 6.0(2)U6(5a)
6.0(2)U6(7)
7.0 7.0(3)I2(1a)
7.0(3)I4(1)
Cisco NX-OS Software Major Release - Nexus 3500 Platform Switches First Fixed Release for This Vulnerability First Fixed Release for This Vulnerability and All Vulnerabilities Described in the Collection of Advisories
Prior to 6.0 Affected; migrate to 6.0(2)A6(5a)
6.0(2)A8(1) 6.0 6.0(2)A6(5a)
6.0(2)A8(1)
Cisco Nexus 4000 Series Switches : CSCuw78669
Cisco NX-OS Software Major Release - Nexus 4000 Series Switches First Fixed Release for This Vulnerability First Fixed Release for This Vulnerability and All Vulnerabilities Described in the Collection of Advisories
4.1 4.1(2)E1(1p) 4.1(2)E1(1p)
Cisco Nexus 5000 Series Switches : CSCux88492
Cisco NX-OS Software
Major Release - Nexus 5000 Series SwitchesFirst Fixed Release for This Vulnerability First Fixed Release for This Vulnerability and All Vulnerabilities Described in the Collection of Advisories Prior to 5.2 Affected; migrate to 5.2(1)N1(9a) 5.2(1)N1(9a)
5.2
5.2(1)N1(9a)
5.2(1)N1(9a)
Cisco Nexus 2000, 5500, 5600 and 6000 Series Switches : CSCux88492
Cisco NX-OS Software
Major Release - Nexus 5500 Platform and 6000 Series SwitchesFirst Fixed Release for This Vulnerability First Fixed Release for This Vulnerability and All Vulnerabilities Described in the Collection of Advisories Prior to 5.2 Affected; migrate to 5.2(1)N1(9a) 7.1(4)N1(1)
5.2
5.2(1)N1(9a)
7.1(4)N1(1)
6.0
Affected; migrate to
7.0(8)N1(1)7.1(4)N1(1)
7.0
7.0(8)N1(1)7.1(4)N1(1)
7.1 7.1(4)N1(1) 7.1(4)N1(1) 7.2 7.2(2)N1(1) 7.2(2)N1(1) 7.3 7.3(0)N1(1) 7.3(0)N1(1)
Cisco Nexus 7000 and 7700 Series Switches : CSCum35502
Cisco NX-OS Software Major Release - Nexus 7000 and 7700 Series Switches First Fixed Release for This Vulnerability First Fixed Release for This Vulnerability and All Vulnerabilities Described in the Collection of Advisories
Prior to 5.2 Affected; migrate to 6.2(16)
7.2(2)D1(1) 5.2
Affected; migrate to 6.2(16)
7.2(2)D1(1)
6.0 Affected; migrate to 6.2(16)
7.2(2)D1(1)
6.1 Affected; migrate to 6.2(16)
7.2(2)D1(1) 6.2 6.2(16)
7.2(2)D1(1) 7.2 7.2(2)D1(1)
7.2(2)D1(1)
7.3 7.3(0)D1(1)
7.3(1)D1(1)
Cisco Nexus 9000 Series Switches NX-OS Mode: CSCum35502
Cisco NX-OS Software Major Release - Nexus 9000 Series Switches
First Fixed Release for This Vulnerability First Fixed Release for This Vulnerability and All Vulnerabilities Described in the Collection of Advisories
6.1 6.1(2)I3(3)
7.0(3)I4(1) 7.0 7.0(3)I1(1)
7.0(3)I4(1)
Cisco MDS 9000 Series Multilayer Switches : CSCum35502
MDS Major Release - MDS First Fixed Release for This Vulnerability
First Fixed Release for This Vulnerability and All Vulnerabilities Described in the Collection of Advisories
5.2 Affected; migrate to 6.2(15)
6.2(15) 6.2 6.2(15)
6.2(15)
7.3 7.3(0)D1(1) 7.3(0)D1(1)
Release Recommendations
For additional assistance in determining the best NX-OS Software release for a Cisco Nexus Switch, refer to the recommended release document for the switch:
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The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
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This vulnerability was found during resolution of a TAC support case.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Version Description Section Status Date 1.0 Initial public release. - Final 2016-October-05
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