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Cisco XR 12000 Series Shared Port Adapters Interface Processor Vulnerability

Advisory ID: cisco-sa-20110525-iosxrspa

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110525-iosxrspa

Revision 1.0

For Public Release 2011 May 25 16:00  UTC (GMT)


Summary

Cisco IOS XR Software Releases 3.9.0, 3.9.1, 3.9.2, 4.0.0, 4.0.1, 4.0.2, and 4.1.0 are affected by a vulnerability that an unauthenticated, remote user could use to trigger a reload of the Shared Port Adapters (SPA) Interface Processor by sending specific IP version 4 (IPv4) packets to an affected device.

Cisco has released free Software Maintenance Units (SMU) that address this vulnerability.

Workarounds that mitigate this vulnerability are not available.

This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110525-iosxrspa.

Affected Products

This vulnerability affects any device that is running Cisco IOS XR Software Releases 3.9.0, 3.9.1, 3.9.2, 4.0.0, 4.0.1, 4.0.2, or 4.1.0 and has a SPA interface processor installed.

Vulnerable Products

This vulnerability affects all Engine 5 Line Cards on the Cisco XR 12000 Series Routers. The engine 5 line cards are the SIP-600, SIP-601, SIP-501, and SIP-401.

To determine the Cisco IOS XR Software release that is running on a Cisco product, administrators can log in to the device and issue the show version command-line interface (CLI) command to display the system banner. The system banner confirms that the device is running Cisco IOS XR Software by displaying text that is similar to "Cisco IOS XR Software". The software version is displayed after the text "Cisco IOS XR Software".

The following example identifies a Cisco XR 12000 Series Router that is running Cisco IOS XR Software Release 3.9.1:

RP/0/0/CPU0:example#show version
Wed Dec 15 10:16:47.117 singa

Cisco IOS XR Software, Version 3.9.1[00]
Copyright (c) 2010 by Cisco Systems, Inc.

ROM: System Bootstrap, Version 12.0(20090302:133850) [rtauro-sw30346-33S 1.23dev(0.36)] DEVELOPMENT SOFTWARE
Copyright (c) 1994-2009 by cisco Systems,  Inc.

example uptime is 26 minutes
System image file is "disk0:c12k-os-mbi-3.9.1/mbiprp-rp.vm"

cisco 12404/PRP (7457) processor with 3145728K bytes of memory.
7457 processor at 1266Mhz, Revision 1.2

1 Cisco 12000 Series Performance Route Processor
1 Cisco 12000 Series SPA Interface Processor-601/501/401
1 Cisco 12000 4 Port Gigabit Ethernet Controller (4 GigabitEthernet)
3 Management Ethernet
5 PLIM_QOS
8 FastEthernet
4 GigabitEthernet/IEEE 802.3 interface(s)
1019k bytes of non-volatile configuration memory.
982304k bytes of disk0: (Sector size 512 bytes).
62420k bytes of disk1: (Sector size 512 bytes).
65536k bytes of Flash internal SIMM (Sector size 256k).

!--- output truncated

To determine if a SPA interface processor is installed in the device, administrators can log in to the device and issue the show platform command to display the system line cards. The output confirms that the device has a SPA interface processor installed by displaying text that is similar to "L3LC Eng 5".

The following example identifies a Cisco XR 12000 Series Router that has an Engine 5 Line Card installed:

RP/0/0/CPU0:example#show platform
Mon May  9 18:40:26.100 PST
Node            Type            PLIM            State           Config State
-----------------------------------------------------------------------------
0/0/CPU0        PRP(Active)     N/A             IOS XR RUN      PWR,NSHUT,MON
0/1/CPU0        L3LC Eng 5+     Jacket Card     IOS XR RUN      PWR,NSHUT,MON
0/1/0           SPA             SPA-8XFE-TX     READY           PWR,NSHUT
0/2/CPU0        L3LC Eng 3      GE-4            IOS XR RUN      PWR,NSHUT,MON

Alternatively, performing the CLI command show diag | include SPA Interface Processor will also show if any SPA interface processor are installed. The following example shows a device with a SIP-401 installed:

RP/0/0/CPU0:example#show diag | include SPA Interface Processor
Mon May  9 18:44:23.069 PST
SLOT  1 (RP/LC 1): Cisco 12000 Series SPA Interface Processor- 401
RP/0/0/CPU0:example#

Products Confirmed Not Vulnerable

No other releases of Cisco IOS XR Software are affected.

The following products are not affected by this vulnerability:

  • Cisco 12000 Series SPA interface processors running Cisco IOS Software
  • Cisco XR 12000 Series Engine 3 Line Cards
  • Cisco ASR 9000 Series Aggregation Services Routers
  • Cisco Carrier Routing System Series Routers

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

Details

Cisco IOS XR Software, which is part of the Cisco IOS Software family, uses a microkernel-based distributed operating system infrastructure. Cisco IOS XR Software runs on the Cisco CRS, Cisco 12000 Series Routers, and Cisco ASR 9000 Series Aggregation Services Routers. This vulnerability only affects the SPA interface processors on the Cisco 12000 Series Routers that are running affected versions of Cisco IOS XR Software.

More information on Cisco IOS XR Software is available at the following link: http://www.cisco.com/en/US/products/ps5845/index.html

This vulnerability affects any device that is running affected releases of Cisco IOS XR Software and has an IPv4 address configured on any of the SPA interface processor interfaces.

When the SPA interface processor receives specific IPv4 packets destined for either a network or a network broadcast address of a configured interface, it will reload and produce an error message that is similar to what is shown in the example that follows. Transit traffic through the device does not trigger this vulnerability.

RP/0/4/CPU0:Example#LC/0/1/CPU0:Apr 26 17:16:31.745 : tx_xbma[85]:
%L2-E5EGRESSQ-4-INTERRUPT : WIM error: reg 0x200000

This vulnerability is documented in Cisco bug ID CSCto45095 (registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2011-1651.

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 .

Cisco XR 12000 Series SPA Interface Processor Vulnerability

Calculate the environmental score of CSCto45095

CVSS Base Score - 7.8

Access Vector

Access Complexity

Authentication

Confidentiality Impact

Integrity Impact

Availability Impact

Network

Low

None

None

None

Complete

CVSS Temporal Score - 6.4

Exploitability

Remediation Level

Report Confidence

Functional

Official-Fix

Confirmed

Impact

Successful exploitation of the vulnerability may result in a reloading of the SPA interface processor. Repeated exploitation could result in a sustained denial of service (DoS) condition.

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.

Major Release

Availability of Repaired Releases

Affected 3.2.X through 3.8.X Based Releases

SMU ID

SMU NAME

First Fixed Release

There are no affected 3.2.X through 3.8.X based releases

Affected 3.9.X Based Releases

SMU ID

SMU NAME

First Fixed Release

3.9.0

None

No SMU available; Contact your Support Organization

No first fixed release; Migrate to 4.0.3, 4.1.1 or later.

3.9.1

AA04896

c12k-os-mbi-3.9.1.CSCto45095

No first fixed release; Migrate to 4.0.3, 4.1.1 or later.

3.9.2

AA04907

c12k-os-mbi-3.9.2.CSCto45095

No first fixed release; Migrate to 4.0.3, 4.1.1 or later.

Affected 4.0.x Based Releases

SMU ID

SMU NAME

First Fixed Release

4.0.0

None

No SMU available; Contact your Support Organization

4.0.3

4.0.1

AA04884

c12k-4.0.1.CSCto45095

4.0.3

4.0.3

Not Affected

Affected 4.1.x Based Releases

SMU ID

SMU NAME

First Fixed Release

4.1.0

AA04976

c12k-4.1.0.CSCto45095

4.1.1

4.1.1

Not Affected

Workarounds

There are no workarounds for this vulnerability.

Using Infrastructure Access Control Lists (iACLs) may help limit the attack surface of this vulnerability. Although it is often difficult to block traffic that transits a network, it is possible to identify traffic that should never be allowed to target infrastructure devices and block that traffic at the border of networks. As a network security best practice, iACLs should be considered a long-term addition to good network security. Because some of the packets used in this vulnerability could utilize UDP as a transport, it could be possible to spoof the sender's IP address, which may defeat ACLs that permit communication to these ports from trusted IP addresses. Unicast RPF should be considered to be used in conjunction to offer a better mitigation solution.

For more information on iACLs, consult the document "Limit Network Access with Access Control Lists" at the following location: http://www.cisco.com/web/about/security/intelligence/CiscoIOSXR.html#19

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/docs/general/warranty/English/EU1KEN_.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 discovered when handling customer support calls.

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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110525-iosxrspa

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-teams@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 1.0

2011-May-25

Initial 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/web/about/security/psirt/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.