A vulnerability in the Border Gateway Protocol (BGP) implementation of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition due to the device unexpectedly reloading. The vulnerability is due to incomplete input validation of the BGP update messages. An attacker could exploit this vulnerability by sending a crafted BGP update message to the targeted device. An exploit could allow the attacker to cause the switch to reload unexpectedly. The Cisco implementation of the BGP protocol only accepts incoming BGP traffic from explicitly defined peers. To exploit this vulnerability, an attacker must be able to send the malicious packets over a TCP connection that appears to come from a trusted BGP peer or inject malformed messages into the victim's BGP network. This would require obtaining information about the BGP peers in the affected system's trusted network. The vulnerability may be triggered when the router receives a malformed BGP message from a peer on an existing BGP session. At least one BGP neighbor session must be established for a router to be vulnerable. 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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180620-nxosbgp This advisory is part of the June 2018 Cisco FXOS and NX-OS Software Security Advisory Collection, which includes 24 Cisco Security Advisories that describe 24 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: June 2018 Cisco FXOS and NX-OS Software Security Advisory Collection.
A vulnerability in the Border Gateway Protocol (BGP) implementation of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition due to the device unexpectedly reloading.
The vulnerability is due to incomplete input validation of the BGP update messages. An attacker could exploit this vulnerability by sending a crafted BGP update message to the targeted device. An exploit could allow the attacker to cause the switch to reload unexpectedly.
The Cisco implementation of the BGP protocol only accepts incoming BGP traffic from explicitly defined peers. To exploit this vulnerability, an attacker must be able to send the malicious packets over a TCP connection that appears to come from a trusted BGP peer or inject malformed messages into the victim's BGP network. This would require obtaining information about the BGP peers in the affected system's trusted network.
The vulnerability may be triggered when the router receives a malformed BGP message from a peer on an existing BGP session. At least one BGP neighbor session must be established for a router to be vulnerable.
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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180620-nxosbgp
This advisory is part of the June 2018 Cisco FXOS and NX-OS Software Security Advisory Collection, which includes 24 Cisco Security Advisories that describe 24 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: June 2018 Cisco FXOS and NX-OS Software Security Advisory Collection.
For information about which Cisco NX-OS Software releases are vulnerable, see the Fixed Software section of this advisory.
Determining if the NX-OS Software Is Vulnerablenxos-switch# show running-config | include "router bgp" router bgp 64512
nxos-switch# show running-config | include "neighbor" neighbor 209.165.201.1 remote-as 64497
Administrators can check the release of Cisco NX-OS Software that is running on a device by using the show version command in the device CLI. The following example shows the output of this command on a device that is running Cisco NX-OS Software Release 7.3(2)D1(1):
Vulmon
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) 2002-2017, 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 7.3(2)D1(1)
system: version 7.3(2)D1(1)
.
.
.
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect the following Cisco products:
Cisco has not investigated whether this vulnerability affects Cisco Nexus 4000 Series Switches, Cisco Nexus 5010 Switches, or Cisco Nexus 5020 Switches because those products have reached end-of-life status. For more information, refer to the End-of-Sale and End-of-Life Announcement for the Cisco Nexus 4000 Series Switch Modules for IBM BladeCenter and the End-of-Sale and End-of-Life Announcement for the Cisco Nexus 5010 and Nexus 5020 Switches.
switch(config)# router bgp 65536 switch(config-router-neighbor)# password BGPpassword
Please refer to the Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide for additional information.
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 regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page, 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 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 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.
Customers are advised to 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. For a complete list of the advisories in the collection and links to them, see Cisco Event Response: June 2018 Cisco FXOS and NX-OS Software Security Advisory Collection.
In the following tables, the left column lists releases of Cisco FXOS or NX-OS Software. The center column indicates whether a release is affected by the vulnerability described in this advisory and the first release that includes the fix for this vulnerability. The right column indicates whether a release is affected by all the vulnerabilities described in this collection of advisories and which release includes fixes for those vulnerabilities.
Nexus 3000 Series Switches: CSCve91387
| Cisco NX-OS Software Release | First Fixed Release for This Vulnerability | First Fixed Release for All Vulnerabilities Described in the Collection of Advisories |
|---|---|---|
| Prior to 7.0(3)I4 |
7.0(3)I4(7) |
7.0(3)I7(4) |
| 7.0(3)I4 |
7.0(3)I4(7) |
7.0(3)I7(4) |
| 7.0(3)I5 |
7.0(3)I6(2) |
7.0(3)I7(4) |
| 7.0(3)I6 |
7.0(3)I6(2) |
7.0(3)I7(4) |
| 7.0(3)I7 | Not vulnerable |
7.0(3)I7(4) |
| Cisco NX-OS Software Release | First Fixed Release for This Vulnerability | First Fixed Release for All Vulnerabilities Described in the Collection of Advisories |
|---|---|---|
| 6.0 | 6.0(2)A8(7) | 7.0(3)I7(4) |
| 7.0.3 | 7.0(3)I7(2) | 7.0(3)I7(4) |
| Cisco NX-OS Software Release | First Fixed Release for This Vulnerability | First Fixed Release for All Vulnerabilities Described in the Collection of Advisories |
|---|---|---|
| 6.0 |
7.1(5)N1(1) |
7.3(3)N1(1) |
| 7.0 | 7.1(5)N1(1) | 7.3(3)N1(1) |
| 7.1 | 7.1(5)N1(1) |
7.3(3)N1(1) |
| 7.2 | 7.3(3)N1(1) |
7.3(3)N1(1) |
| 7.3 | 7.3(3)N1(1) |
7.3(3)N1(1) |
| Cisco NX-OS Software Release | First Fixed Release for This Vulnerability | First Fixed Release for All Vulnerabilities Described in the Collection of Advisories |
|---|---|---|
| 6.2 | 6.2(20) | 8.1(2) or 8.2(1) |
| 7.2 | 7.3(2)D1(1) | 8.1(2) or 8.2(1) |
| 7.3 | 7.3(2)D1(1) |
8.1(2) or 8.2(1) |
| 8.0 | 8.1(2) | 8.1(2) or 8.2(1) |
| 8.1 | 8.1(2) | 8.1(2) or 8.2(1) |
| 8.2 | 8.2(1) | 8.1(2) or 8.2(1) |
| Cisco NX-OS Software Release | First Fixed Release for This Vulnerability | First Fixed Release for All Vulnerabilities Described in the Collection of Advisories |
|---|---|---|
| Prior to 12.1/2.1 |
12.1(3h)/2.1(3h) | 13.1(1i)/3.1(1i) |
| 12.1/2.1 | 12.1(3h)/2.1(3h) |
13.1(1i)/3.1(1i) |
| 12.2/2.2 |
12.2(3j)/2.2(3j) |
13.1(1i)/3.1(1i) |
| 12.3/2.3 |
13.0(1k)/3.0(1k) |
13.1(1i)/3.1(1i) |
| 13.0/3.0 |
13.0(1k)/3.0(1k) |
13.1(1i)/3.1(1i) |
| 13.1/3.1 | Not vulnerable | 13.1(1i)/3.1(1i) |
| Cisco NX-OS Software Release | First Fixed Release for This Vulnerability | First Fixed Release for All Vulnerabilities Described in the Collection of Advisories |
|---|---|---|
| Prior to 7.0(3)I4 |
7.0(3)I4(7) |
7.0(3)I7(4) |
| 7.0(3)I4 | 7.0(3)I4(7) | 7.0(3)I7(4) |
| 7.0(3)I5 | 7.0(3)I6(2) | 7.0(3)I7(4) |
| 7.0(3)I6 | 7.0(3)I6(2) | 7.0(3)I7(4) |
| 7.0(3)I7 | Not vulnerable |
7.0(3)I7(4) |
| Cisco NX-OS Software Release | First Fixed Release for This Vulnerability | First Fixed Release for All Vulnerabilities Described in the Collection of Advisories |
|---|---|---|
| 7.0 | 7.0(3)F2(2) |
7.0(3)F3(3a) |
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.
This vulnerability was found during resolution of a TAC support case.
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.
| Version | Description | Section | Status | Date |
|---|---|---|---|---|
| 1.0 | Initial public release. | - | Final | 2018-June-20 |
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