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ESB-2016.0288 - [Cisco] Cisco Nexus 9000 Series ACI Mode Switches: Denial of service - Remote/unauthenticated

Date: 04 February 2016

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2016.0288
  Cisco Nexus 9000 Series ACI Mode Switch ICMP Record Route Vulnerability
                              4 February 2016

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Cisco Nexus 9000 Series ACI Mode Switches
Publisher:         Cisco Systems
Operating System:  Cisco
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2015-6398  

Original Bulletin: 
   http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160203-n9knci

- --------------------------BEGIN INCLUDED TEXT--------------------

Cisco Nexus 9000 Series ACI Mode Switch ICMP Record Route Vulnerability

High

Advisory ID:

cisco-sa-20160203-n9knci

Published:

2016 February 3 16:00 GMT

Version 1.0:

Final

CVSS Score:

Base - 7.8

Workarounds:

Yes

Cisco Bug IDs:

CSCuq57512

CVE-2015-6398

CWE-399

Summary

A vulnerability in the ICMP implementation in the Cisco Nexus 9000 Series 
Application Centric Infrastructure (ACI) Mode Switch could allow an 
unauthenticated, remote attacker to cause the switch to reload, resulting in a
denial of service (DoS) condition.

The vulnerability is due to improper handling of an ICMP packet with the IPv4
Type 7 option for record route. An attacker could exploit this vulnerability 
by sending an ICMP packet with the record route option to an interface on the
affected switch. An exploit could allow the attacker to cause a DoS condition
because the switch will reload each time the ICMP packet is received.

Cisco has released software updates that address this vulnerability. A 
workaround that addresses this vulnerability is available.

This advisory is available at the following link: 
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160203-n9knci

Affected Products

Vulnerable Products

Cisco Nexus 9000 Series ACI Mode Switches running software versions prior to 
release 11.0(1c) are vulnerable.

Products Confirmed Not Vulnerable

No other Cisco products are currently known to be affected by this 
vulnerability. Cisco Nexus 9000 Series Switches and Cisco Application Policy 
Infrastructure Controller (APIC) are not affected.

Indicators of Compromise

This vulnerability will cause the affected device to reload and write a core 
file. Contact the Cisco Technical Assistance Center (TAC) to review the core 
file and confirm whether the device has been compromised by this 
vulnerability.

Workarounds

The workaround for this vulnerability is to drop all ICMP packets and should 
not be applied unless the device has been exploited by this vulnerability. 
This workaround can be applied only when working with the Cisco TAC.

To apply the workaround, the administrator must log in as the root user on the
Cisco Nexus 9000 Series ACI Mode Switch. The command iptables -I INPUT 1 -p 
ICMP -j DROP will drop ICMP packets to the affected switch. The ICMP drop 
action can be removed with the command iptables -D INPUT 1.

Fixed Software

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 Versions

The Cisco Nexus 9000 Series ACI Mode Switch ICMP Record Route Vulnerability is
fixed in versions 11.0(1c) and later. The Cisco Nexus 9000 Series ACI Mode 
software can be downloaded from the Software Center on Cisco.com by visiting 
http://www.cisco.com/cisco/software/navigator.html and choosing Downloads Home
> Products > Switches > Data Center Switches > Nexus 9000 Series Switches.

Exploitation and Public Announcements

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.

Source

This vulnerability was found during investigation of a customer issue by the 
Cisco TAC.

URL

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160203-n9knci

Revision History

Version Description 		Section Status 	Date

1.0 	Initial public release. -	Final 	2016-February-03

Legal Disclaimer

THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF 
GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS
FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS
LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO 
CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.

A standalone copy or paraphrase of the text of this document that omits the 
distribution URL is an uncontrolled copy and may lack important information or
contain factual errors. The information in this document is intended for end 
users of Cisco products.

- --------------------------END INCLUDED TEXT--------------------

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===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072

Internet Email: auscert@auscert.org.au
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