Summary

• A vulnerability in the ingress packet processing functionality of the Cisco Virtualized Packet Core-Distributed Instance (VPC-DI) Software could allow an unauthenticated, remote attacker to cause both control function (CF) instances on an affected system to reload, resulting in a denial of service (DoS) condition.
  
  The vulnerability is due to insufficient handling of user-supplied data by the affected software. An attacker could exploit this vulnerability by sending malicious traffic to the internal distributed instance (DI) network address on an affected system. A successful exploit could allow the attacker to cause an unhandled error condition on the affected system, which would cause the CF instances to reload and consequently cause the entire VPC to reload, resulting in the disconnection of all subscribers and a DoS condition on the affected system.
  
  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-20180207-vpcdi

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco Virtualized Packet Core−Distributed Instance (VPC−DI) Software running any release of the Cisco StarOS operating system prior to the first fixed release.
  
  To determine whether a vulnerable release of Cisco StarOS is running on a VPC-DI instance, administrators can use the show version command in the device CLI. The following example shows the output of the command for a VPC−DI instance that is running Cisco StarOS Release 19.3.v5 (VPC−DI Release N4.2.5). Please refer to the table in the Fixed Software section, which lists all major releases of both VPC-DI and Cisco StarOS software respectively.
  
  

  [local]VPC-001# show version
  
  Active Software:
    Image Version:                  19.3.v5
    Image Build Number:             65002
    Image Description:              Deployment_Build
    Image Date:                     Wed Sep 14 05:35:14 EDT 2016
    Boot Image:                     /flash/qvpc-di-19.3.v5.bin 

  Products Confirmed Not Vulnerable

  No other Cisco products are currently known to be affected by this vulnerability.
  
  Cisco has confirmed that this vulnerability does not affect the following Cisco products:
  

  • Virtualized Packet Core−Single Instance (VPC−SI) Software
  • ASR 5000 Series Aggregation Services Routers
  • Elastic Services Controllers
  • Ultra Automation Services

Details

• A DI network interconnects the virtual machines (VMs) in a VPC−DI instance to enable the VMs to communicate with each other. The DI network should be a unique, isolated network reserved for the exclusive use of a single VPC−DI instance. No other devices should be connected to the DI network. If more than one VPC−DI instance is instantiated in the same data center, each instance should have its own DI network.
  
  To exploit this vulnerability, the attacker needs to be able to send TCP packets to the DI network interface of a VPC−DI instance via IPv4.
  
  The vulnerable code exists only in VPC−DI Software. This vulnerability does not exist in Cisco VPC−SI Software or the other Cisco products listed in the “Products Confirmed Not Vulnerable” section.
  

Workarounds

• There are no workarounds that address this vulnerability.

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: 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

  In the following table, the left column lists major releases of Cisco VPC-DI Software and the middle column lists major releases of Cisco StarOS. The right 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.

  Customers should upgrade to an appropriate release as indicated in the following table:

  
  

  Cisco VPC-DI Major Release	Cisco StarOS Major Release	Fixed Release for Cisco Bug CSCve17656
  N4.0	19.2	Affected; migrate to N5.1.9 (21.1.v7)
  N4.2	19.3	Affected; migrate to N5.1.9 (21.1.v7)
  N4.5	20.0	Affected; migrate to N5.1.9 (21.1.v7)
  N4.6	20.1	Affected; migrate to N5.1.9 (21.1.v7)
  N4.7	20.2	Affected; migrate to N5.1.9 (21.1.v7)
  N5.0	21.0	Affected; migrate to N5.1.9 (21.1.v7)
  N5.1	21.1	N5.1.9 (21.1.v7)
  N5.5	21.3	N5.5.0 (21.3.v10)

  
  

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 internal security testing.

URL

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180207-vpcdi

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2018-February-07

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