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[Full-disclosure] Cisco Security Advisory: Cisco ONS Platform Crafted Packet Vulnerability

From: Cisco Systems Product Security Incident Response Team <psirt_at_nospam>
Date: Wed Jan 14 2009 - 16:00:00 GMT
To: full-disclosure@lists.grok.org.uk


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Cisco Security Advisory: Cisco ONS Platform Crafted Packet Vulnerability

Advisory ID: cisco-sa-20090114-ons

http://www.cisco.com/warp/public/707/cisco-sa-20090114-ons.shtml

Revision 1.0

For Public Release 2009 January 14 1600 UTC (GMT)

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Summary


The Cisco ONS 15300 series Edge Optical Transport Platform, the Cisco ONS 15454 Optical Transport Platform, the Cisco ONS 15454 SDH Multiservice Platform, and the Cisco ONS 15600 Multiservice Switching Platform contains a vulnerability when processing TCP traffic streams that may result in a reload of the device control card.

Cisco has released free software updates that address this vulnerability.

There are no workarounds that mitigate this vulnerability. Several mitigations exist that can limit the exposure of this vulnerability.

This advisory is posted at
http://www.cisco.com/warp/public/707/cisco-sa-20090114-ons.shtml

Affected Products


Vulnerable Products +------------------

The following Cisco ONS products are vulnerable if running affected software versions:

  • Cisco ONS 15310-CL and 15310-MA
  • Cisco ONS 15327
  • Cisco ONS 15454 and 15454 SDH
  • Cisco ONS 15600

Consult the section "Software Versions and Fixes" within this advisory for affected software versions. To determine your software version, view the Help > About window on the CTC management software).

Products Confirmed Not Vulnerable +--------------------------------

The following Cisco ONS products are confirmed not vulnerable:

  • Cisco ONS 15800 Series
  • Cisco ONS 15500 Series Extended Service Platform
  • Cisco ONS 15302
  • Cisco ONS 15305
  • Cisco ONS 15200 Series Metro DWDM Systems
  • Cisco ONS 15190 Series IP Transport Concentrator

No other Cisco products are currently known to be affected by this vulnerability.

Details


The affected Cisco 15310-CL, 15310-MA, ONS 15327, ONS 15454, ONS 15454 SDH, and ONS 15600 hardware is managed through the CTX, CTX2500, XTC, TCC/TCC+/TCC2/TCC2P, TCCi/TCC2/TCC2P, and TSC control cards respectively. These control cards are usually connected to a Data Communications Network (DCN). In this context the term DCN is used to denote the network that transports management information between a management station and the network entity (NE). This definition of DCN is sometimes referred to as Management Communication Network (MCN). The DCN is usually physically or logically separated from the optical data network and isolated from the Internet. This limits the exposure to the exploitation of this vulnerability from the Internet.

A crafted stream of TCP traffic to the control cards on a node will result in a reset of the corresponding control cards on this node. A complete 3-way handshake is required on any open TCP port to be able to exploit this vulnerability.

The timing for the data channels traversing the switch is provided by the control cards.

When an active and a standby Cisco ONS 15310-MA, ONS 15310-CL, ONS 15327, ONS 15454 or ONS 15454 SDH control card reloads at the same time, the synchronous data channels traversing the switch drop traffic until the card comes back online. Asynchronous data channels traversing the switch are not impacted. Manageability functions provided by the network element using the CTX, CTX2500, XTC or TCC/ TCC+/TCC2/TCC2P control cards are not available until the control card comes back online.

On the Cisco ONS 15600 hardware, whenever both the active and standby control cards are rebooting at the same time, there is no impact to the data channels traversing the switch because the TSC performs a software reset which does not impact the timing being provided by the TSC for the data channels.

Manageability functions provided by the network element through the TSC control cards are not available until the control card comes back online.

This vulnerability is documented in Cisco bug ID CSCsr41128 and has been assigned Common Vulnerabilities and Exposures (CVE) identifier CVE-2008-3818.

Vulnerability Scoring Details


Cisco has provided scores for the vulnerabilities in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this Security Advisory is done in accordance with CVSS version 2.0.

CVSS is a standards-based scoring method that conveys vulnerability severity and helps determine urgency and priority of response.

Cisco has provided a base and temporal score. Customers can then compute environmental scores to assist in determining the impact of the vulnerability in individual networks.

Cisco has provided an FAQ to answer additional questions regarding CVSS at

http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html

Cisco has also provided a CVSS calculator to help compute the environmental impact for individual networks at

http://intellishield.cisco.com/security/alertmanager/cvss

CVSS Base Score - 7.8 Access Vector : Network Access Complexity : Low Authentication : None Confidentiality Impact: None Integrity Impact : None Availability Impact : Complete

CVSS Temporal Score - 6.4 Exploitability : Functional Remediation Level : Official-Fix Report Confidence : Confirmed

Impact


Successful exploitation of this vulnerability will result in a reset of the node's control card. Repeated attempts to exploit this vulnerability could result in a sustained DoS condition, dropping the synchronous data channels traversing the switch (Cisco ONS 15310-MA, ONS 15310-CL, ONS 15327, ONS 15454, ONS 15454 SDH) and preventing manageability functions provided by the network element control cards (all ONS switches) until the control card comes back online.

Software Versions and Fixes


When considering software upgrades, also consult http://www.cisco.com/go/psirt and any subsequent advisories to determine exposure and a complete upgrade solution.

In all cases, customers should exercise caution to be certain the devices to be upgraded contain sufficient memory and that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, contact the Cisco Technical Assistance Center (TAC) or your contracted maintenance provider for assistance. +-------------------------------------------------------------------------+ | Affected Major Release | First Fixed Release | |---------------------------------+---------------------------------------| | 7.0 | Note: Releases prior to 7.0.2 are not | | | vulnerable. First fixed in 7.0.7 | |---------------------------------+---------------------------------------| | 7.2 | Note: Releases prior to 7.2.2 are not | | | vulnerable. First fixed in 7.2.3 | |---------------------------------+---------------------------------------| | 8.0 | Vulnerable; migrate to 8.5.3 or | | | later. | |---------------------------------+---------------------------------------| | 8.5 | Note: Releases prior to 8.5.1 are not | | | vulnerable. First fixed in 8.5.3 | |---------------------------------+---------------------------------------| | 9.0 | Not vulnerable. | +-------------------------------------------------------------------------+

Note: Releases prior to 7.0 are not affected by this vulnerability.

Workarounds


There are no workarounds for this vulnerability. The following general mitigation actions help prevent remote exploitation:

  • Isolate DCN: Ensuring the DCN is physically or logically separated from the customer network and isolated from the Internet will limit the exposure to the exploitation of these vulnerabilities from the Internet or customer networks.
  • Apply Transit Access Control Lists: Apply access control lists (ACLs) on routers / switches / firewalls installed in front of the vulnerable network devices such that TCP/IP traffic destined for the CTX, CTX2500, XTC, TCC2 /TCC2+/TCC2P, or TSC control cards on the ONS is allowed only from the network management workstations. For examples on how to apply ACLs on Cisco routers, refer to the white paper "Transit Access Control Lists: Filtering at Your Edge", which is available at the following link: http://www.cisco.com/en/US/customer/tech/tk648/tk361/technologies_white_paper09186a00801afc76.shtml

Additional mitigations that can be deployed on Cisco devices within the network are available in the Cisco Applied Mitigation Bulletin companion document for this advisory, which is available at the following link:
http://www.cisco.com/warp/public/707/cisco-amb-20090114-ons.shtml

Obtaining Fixed Software


Cisco has released free software updates that address these vulnerabilities. Prior to deploying software, customers should consult their maintenance provider or check the software for feature set compatibility and known issues specific to their environment.

Customers may only install and expect support for the feature sets they have purchased. By installing, downloading, accessing or otherwise using such software upgrades, customers agree to be bound by the terms of Cisco's software license terms found at http://www.cisco.com/en/US/products/prod_warranties_item09186a008088e31f.html or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml

Do not contact psirt@cisco.com or security-alert@cisco.com for software upgrades.

Customers with Service Contracts +-------------------------------

Customers with contracts should obtain upgraded software through their regular update channels. For most customers, this means that upgrades should be obtained through the Software Center on Cisco's worldwide website at http://www.cisco.com

Customers using Third Party Support Organizations +------------------------------------------------

Customers whose Cisco products are provided or maintained through prior or existing agreements with third-party support organizations, such as Cisco Partners, authorized resellers, or service providers should contact that support organization for guidance and assistance with the appropriate course of action in regards to this advisory.

The effectiveness of any workaround or fix is dependent on specific customer situations, such as product mix, network topology, traffic behavior, and organizational mission. Due to the variety of affected products and releases, customers should consult with their service provider or support organization to ensure any applied workaround or fix is the most appropriate for use in the intended network before it is deployed.

Customers without Service Contracts +----------------------------------

Customers who purchase direct from Cisco but do not hold a Cisco service contract, and customers who purchase through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should acquire upgrades by contacting the Cisco Technical Assistance Center (TAC). TAC contacts are as follows.

  • +1 800 553 2447 (toll free from within North America)
  • +1 408 526 7209 (toll call from anywhere in the world)
  • e-mail: tac@cisco.com

Customers should have their product serial number available and be prepared to give the URL of this notice as evidence of entitlement to a free upgrade. Free upgrades for non-contract customers must be requested through the TAC.

Refer to http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including localized telephone numbers, and instructions and e-mail addresses for use in various languages.

Exploitation and Public Announcements


The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.

This vulnerability was found by reviewing Cisco TAC service requests.

Status of this Notice: FINAL


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 stand-alone copy or Paraphrase of the text of this document that omits the distribution URL in the following section is an uncontrolled copy, and may lack important information or contain factual errors.

Distribution


This advisory is posted on Cisco's worldwide website at:

http://www.cisco.com/warp/public/707/cisco-sa-20090114-ons.shtml

In addition to worldwide web posting, a text version of this notice is clear-signed with the Cisco PSIRT PGP key and is posted to the following e-mail and Usenet news recipients.

  • cust-security-announce@cisco.com
  • first-bulletins@lists.first.org
  • bugtraq@securityfocus.com
  • vulnwatch@vulnwatch.org
  • cisco@spot.colorado.edu
  • cisco-nsp@puck.nether.net
  • full-disclosure@lists.grok.org.uk
  • comp.dcom.sys.cisco@newsgate.cisco.com

Future updates of this advisory, if any, will be placed on Cisco's worldwide website, but may or may not be actively announced on mailing lists or newsgroups. Users concerned about this problem are encouraged to check the above URL for any updates.

Revision History


+---------------------------------------+ | Revision | | Initial | | 1.0 | 2009-January-14 | public | | | | release | +---------------------------------------+

Cisco Security Procedures


Complete information on reporting security vulnerabilities in Cisco products, obtaining assistance with security incidents, and registering to receive security information from Cisco, is available on Cisco's worldwide website at
http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html This includes instructions for press inquiries regarding Cisco security notices. All Cisco security advisories are available at http://www.cisco.com/go/psirt
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