Cisco FXOS and NX-OS Lightweight Directory Access Protocol Denial of Service Vulnerabilities

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Updated:March 6, 2019
Document ID:1551888505328944

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Cisco Security Advisory

Cisco FXOS and NX-OS Lightweight Directory Access Protocol Denial of Service Vulnerabilities

High
Advisory ID:
cisco-sa-20190306-nxosldap
First Published:
2019 March 6 16:00 GMT
Version 1.0:
Final
Workarounds:
No workarounds available
CVE-2019-1597
CVE-2019-1598
CVSS Score:
Base 8.6Click Icon to Copy Verbose Score
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X
CVE-2019-1597
CVE-2019-1598

Summary

  • Multiple vulnerabilities in the implementation of the Lightweight Directory Access Protocol (LDAP) feature in Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition.

    The vulnerabilities are due to the improper parsing of LDAP packets by an affected device. An attacker could exploit these vulnerabilities by sending an LDAP packet crafted using Basic Encoding Rules (BER) to an affected device. The LDAP packet must have a source IP address of an LDAP server configured on the targeted device. A successful exploit could cause the affected device to reload, resulting in a DoS condition.

    Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.

    This advisory is available at the following link:
    https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190306-nxosldap

    This advisory is part of the March 2019 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication, which includes 25 Cisco Security Advisories that describe 26 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: March 2019 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.

Affected Products

  • Vulnerable Products

    These vulnerabilities affect the following Cisco products if they are running a vulnerable release of Cisco FXOS Software or Cisco NX-OS Software and are configured for remote LDAP authentication:
    • Firepower 4100 Series Next-Generation Firewalls
    • Firepower 9300 Security Appliance
    • MDS 9000 Series Multilayer Switches
    • Nexus 3000 Series Switches
    • Nexus 3500 Platform Switches
    • Nexus 7000 Series Switches
    • Nexus 7700 Series Switches
    • Nexus 9000 Series Switches in standalone NX-OS mode
    • UCS 6200 Series Fabric Interconnects
    • UCS 6300 Series Fabric Interconnects

    For information about which Cisco FXOS Software and Cisco NX-OS Software releases are vulnerable, see the Fixed Software section of this advisory.

    Determining the Cisco FXOS LDAP Configuration

    To determine whether a Nexus device is configured for LDAP-based authentication, authorization, and accounting (AAA), administrators can use the show ldap-server CLI command. Output after the following LDAP servers are configured header indicates that a device is vulnerable. For additional information about AAA configuration for FXOS-based devices, customers can refer to the Configuring AAA section of the Cisco FXOS CLI Configuration Guide. 

    fxos# show ldap-server 
 timeout : 30
        port : 0
      baseDN :
user profile attribute :
search filter : cn=$userid
  use groups : 0
recurse groups : 0
group attribute : memberOf
total number of servers : 1
 
following LDAP servers are configured:
    ldap1:
        timeout: 30    port: 389    rootDN: DC=cisco-firepower-aaa1,DC=qalab0,DC=com0,DC=cisco-firepower-aaa2,DC=qalab1,DC=com1,DC=cisco-firepower-aaa3,DC=qalab2,DC=com2,DC=cisco-firepower-aaa4,DC=qalab3,DC=com3,DC=cisco-firepower-aaa5,DC=qalab4,DC=com4,DC=cisco-firepower-aaa6,DC=qalab5,DC=qalab006
        enable-ssl: true
.
.
.

    Determining the Cisco NX-OS LDAP Configuration

    To determine whether a Nexus device is configured for the LDAP feature, administrators can use the show running-config | include "ldap-server host" command from the NX-OS CLI and verify that the feature is enabled.

    nxos-switch# show running-config | include "ldap-server host"
     ldap-server host ...

    For additional information on NX-OS LDAP configuration, customers can refer to the Configuring LDAP chapter of the Cisco Security Configuration Guide.

    Determining the Cisco FXOS Software Release

    Administrators can check the release of Cisco FXOS Software that is running on a device by using the following commands in the device CLI or by navigating to the Overview tab in the Admin portal. The following example shows the output of the show version CLI command on a device that is running Cisco FXOS Software Release 2.2(2.14), as identified in the Package-Vers field of the command output:

    QP4120B1 # scope system
QP4120B1 /system # show version
FPRM:
Running-Vers: 4.2(2.15)
Package-Vers: 2.2(2.14)
Activate-Status: Ready

    Determining the Cisco NX-OS Software Release

    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 7.0(3)I5(1):

    nxos-switch# show version
Cisco Nexus Operating System (NX-OS) Software
TAC support: http://www.cisco.com/tac
Copyright (C) 2002-2016, Cisco and/or its affiliates.
All rights reserved.
The copyrights to certain works contained in this software are
owned by other third parties and used and distributed under their own
licenses, such as open source.  This software is provided "as is," and
unless otherwise stated, there is no warranty, express or implied, 
including but not limited to warranties of merchantability and fitness 
for a particular purpose. Certain components of this software are 
licensed under the GNU General Public License (GPL) version 2.0 or 
GNU General Public License (GPL) version 3.0  or the GNU
Lesser General Public License (LGPL) Version 2.1 or 
Lesser General Public License (LGPL) Version 2.0. 
A copy of each such license is available at
http://www.opensource.org/licenses/gpl-2.0.php and
http://opensource.org/licenses/gpl-3.0.html and
http://www.opensource.org/licenses/lgpl-2.1.php and
http://www.gnu.org/licenses/old-licenses/library.txt.
Software
  BIOS: version 07.57
  NXOS: version 7.0(3)I5(1) [build 7.0(3)I5(0.9)]
  BIOS compile time:  06/29/2016
  NXOS image file is: bootflash:///nxos.7.0.3.I5.0.9.bin
  NXOS compile time:  8/1/2016 23:00:00 [08/02/2016 00:30:32]
  .
  .
  .

    Products Confirmed Not Vulnerable

    Only products listed in the Vulnerable Products section of this advisory are known to be affected by these vulnerabilities.

    Cisco has confirmed that these vulnerabilities do not affect the following Cisco products:

    • Firepower 2100 Series Firewalls
    • Nexus 1000V Switch for KVM
    • Nexus 1000V Switch for Microsoft Hyper-V
    • Nexus 1000V Switch for VMware vSphere
    • Nexus 1100 Series Cloud Services Platforms
    • Nexus 2000 Series Fabric Extenders
    • Nexus 3600 Platform Switches
    • Nexus 5500 Platform Switches
    • Nexus 5600 Platform Switches
    • Nexus 6000 Series Switches
    • Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode
    • Nexus 9500 R-Series Line Cards and Fabric Modules
    • UCS 6400 Series Fabric Interconnects

Workarounds

  • There are no workarounds that address these vulnerabilities.

Fixed Software

  • Cisco has released free software updates that address the vulnerabilities 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: https://www.cisco.com/c/en/us/products/end-user-license-agreement.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 be upgraded 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 TAC: https://www.cisco.com/c/en/us/support/web/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 are advised to upgrade to an appropriate release as indicated in the applicable table in this section. To help ensure a complete upgrade solution, customers should consider that this advisory is part of a bundled publication. The following page provides a complete list of bundle advisories: Cisco Event Response: March 2019 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.

    In the following tables, the left column lists releases of Cisco FXOS Software or Cisco NX-OS Software. The center column indicates whether a release is affected by the vulnerabilities described in this advisory and the first release that includes the fix for these vulnerabilities. The right column indicates whether a release is affected by all the vulnerabilities described in this bundle and which release includes fixes for those vulnerabilities.

    Although the releases listed in the right column of each table include fixes for the vulnerabilities, the fix related to the Cisco NX-OS Software Image Signature Verification Vulnerability requires a BIOS upgrade as part of the software upgrade. Customers who are upgrading the software for any of the following products are advised to refer to this advisory for further details about the BIOS upgrade and affected product IDs and BIOS versions:

    • Nexus 3000 Series Switches
    • Nexus 9000 Series Fabric Switches in ACI mode
    • Nexus 9000 Series Switches in standalone NX-OS mode
    • Nexus 9500 R-Series Line Cards and Fabric Modules

    Firepower 4100 Series Next-Generation Firewalls: CSCvd40241 and CSCvd57308

    Cisco FXOS Software Release First Fixed Release for These Vulnerabilities First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories
    1.1
    		 2.0.1.201
    		 2.2.2.91
    2.0 2.0.1.201
    		 2.2.2.91 
    2.1 2.2.2.54
    		 2.2.2.91 
    2.2 2.2.2.54
    		 2.2.2.91 
    2.3 2.3.1.75
    		 2.3.1.110 
    2.4 Not vulnerable 2.4.1.122 

    Firepower 9300 Security Appliance: CSCvd40241 and CSCvd57308

    Cisco FXOS Software Release First Fixed Release for These Vulnerabilities First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories
    1.1
    		 2.0.1.201 2.2.2.91
    2.0 2.0.1.201 2.2.2.91 
    2.1 2.2.2.54 2.2.2.91 
    2.2 2.2.2.54 2.2.2.91 
    2.3 2.3.1.75 2.3.1.110
    2.4 Not vulnerable 2.4.1.122

    MDS 9000 Series Multilayer Switches: CSCve57820 and CSCve02867

    Cisco NX-OS Software Release First Fixed Release for These Vulnerabilities First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories
    5.2
    		 6.2(21) 6.2(27)
    6.2 6.2(21) 6.2(27)
    7.3 8.2(1) 8.3(2)
    8.1 8.2(1) 8.3(2)  
    8.2 Not vulnerable 8.3(2)  
    8.3 Not vulnerable 8.3(2)  

    Nexus 3000 Series Switches: CSCve58224 and CSCve02858

    Cisco NX-OS Software Release First Fixed Release for These Vulnerabilities First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories
    Prior to 7.0(3)I4
    		 7.0(3)I4(7) 7.0(3)I7(6)
    7.0(3)I4 7.0(3)I4(7) 7.0(3)I7(6)
    7.0(3)I5 7.0(3)I7(1) 7.0(3)I7(6)
    7.0(3)I6 7.0(3)I7(1) 7.0(3)I7(6) 
    7.0(3)I7 7.0(3)I7(1) 7.0(3)I7(6)
    9.2(1) Not vulnerable
    		  9.2(2)

    Nexus 3500 Platform Switches: CSCve02871

    Cisco NX-OS Software Release First Fixed Release for These Vulnerabilities First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories
    Prior to 6.0(2)A8
    		6.0(2)A8(11)  6.0(2)A8(11) 
    6.0(2)A8
    		 6.0(2)A8(11)
    		 6.0(2)A8(11) 
    7.0(3) 7.0(3)I7(2)
    		 7.0(3)I7(6)
    9.2 Not vulnerable 9.2(2)

    Nexus 7000 and 7700 Series Switches: CSCve57820 and CSCve02867

    Cisco NX-OS Software Release First Fixed Release for These Vulnerabilities First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories
    Prior to 6.2
    		 6.2(20) 6.2(22)
    6.2
    		 6.2(20) 6.2(22)
    7.2 7.3(2)D1(1) 8.2(3)
    7.3 7.3(2)D1(1) 8.2(3)
    8.0 8.2(1) 8.2(3)
    8.1 8.2(1) 8.2(3)
    8.2 Not vulnerable 8.2(3)
    8.3 Not vulnerable
    		 8.3(2)

    Nexus 9000 Series Switches in Standalone NX-OS Mode: CSCve02865 and CSCve57816

    Cisco NX-OS Software Release First Fixed Release for These Vulnerabilities First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories
    Prior to 7.0(3)I4
    		 7.0(3)I4(7) 7.0(3)I7(6)
    7.0(3)I4 7.0(3)I4(7) 7.0(3)I7(6)
    7.0(3)I5 7.0(3)I7(1) 7.0(3)I7(6)
    7.0(3)I6 7.0(3)I7(1) 7.0(3)I7(6) 
    7.0(3)I7 7.0(3)I7(1) 7.0(3)I7(6)
    9.2(1) Not vulnerable
    		 9.2(2)

    UCS 6200 and 6300 Fabric Interconnects: CSCve02855

    Cisco NX-OS Software Release First Fixed Release for These Vulnerabilities First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories
    Prior to 3.1
    		 3.2(2b) 3.2(3j)
    3.1 3.2(2b) 3.2(3j)
    3.2 3.2(2b) 3.2(3j)
    4.0 Not vulnerable
    		 4.0(2a) 

    Additional Resources

    For help determining the best Cisco NX-OS Software release for a Cisco Nexus Switch, administrators can refer to the following Recommended Releases documents. If a security advisory recommends a later release, Cisco recommends following the advisory guidance.

    Cisco MDS Series Switches
    Cisco Nexus 1000V for VMware Switch
    Cisco Nexus 3000 Series and 3500 Series Switches
    Cisco Nexus 5000 Series Switches
    Cisco Nexus 5500 Platform Switches
    Cisco Nexus 6000 Series Switches
    Cisco Nexus 7000 Series Switches
    Cisco Nexus 9000 Series Switches
    Cisco Nexus 9000 Series ACI-Mode Switches

    For help determining the best Cisco NX-OS Software release for Cisco UCS, refer to the Recommended Releases documents in the release notes for the device.

Exploitation and Public Announcements

  • The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.

Source

  • These vulnerabilities were found during internal security testing.

Cisco Security Vulnerability Policy

  • 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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Related to This Advisory

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Revision History

  • Version Description Section Status Date
    1.0 Initial public release. — Final 2019-March-06
    Show Less

Cisco Security Vulnerability Policy

  • 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.

Subscribe to Cisco Security Notifications

Related to This Advisory