Advisory ID: cisco-sa-20120530-iosxr
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120530-iosxr
Revision 2.1
Last Updated 2012 August 23 20:37 UTC (GMT)
For Public Release 2012 May 30 16:00 UTC (GMT)
Contents
Summary
Affected Products
Details
Vulnerability Scoring Details
Impact
Software Versions and Fixes
Workarounds
Obtaining Fixed Software
Exploitation and Public Announcements
Status of This Notice: Final
Distribution
Revision History
Cisco Security Procedures
Summary
Cisco IOS XR Software contains a vulnerability when handling crafted packets that may result in a denial of service condition. The vulnerability only exists on Cisco 9000 Series Aggregation Services Routers (ASR) Route Switch Processor (RSP-4G and RSP-8G), Route Switch Processor 440 (RSP440), and Cisco Carrier Routing System (CRS) Performance Route Processor (PRP). The vulnerability is a result of improper handling of crafted packets and could cause the route processor, which processes the packets, to be unable to transmit packets to the fabric.Cisco has released free software updates that address this vulnerability. This advisory is available at the following link:
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120530-iosxr
Affected Products
Vulnerable Products
The following example identifies a Cisco ASR 9000 series device that is running Cisco IOS XR Software Release 4.2.0:
The following example identifies a Cisco CRS series device that is running Cisco IOS XR Software Release 4.0.4:RP/0/RSP1/CPU0:ASR9006-D#show version | inc Cisco IOS XR Software Fri Apr 27 22:40:32.486 UTC
Cisco IOS XR Software, Version 4.2.0[Default]
Additional information about Cisco IOS XR Software release naming conventions is available in "White Paper: Cisco IOS Reference Guide" at the following link: http://www.cisco.com/web/about/security/intelligence/ios-ref.html#9RP/0/RP0/CPU0:CRS-G#show version | inc Cisco IOS XR Software Fri Apr 27 22:28:14.304 UTC Cisco IOS XR Software, Version 4.0.4[Default]
Additional information about Cisco IOS XR Software time-based release model is available in "White Paper: Guidelines for Cisco IOS XR Software" at the following link: http://www.cisco.com/en/US/prod/collateral/iosswrel/ps8803/ps5845/product_bulletin_c25-478699.html
In order to determine whether a Cisco ASR 9000 series device with affected software is using an RSP440, the following command can be run:
Only devices that are equipped with Performance Route Processors are affected. In order to determine whether a Cisco CRS series device with affected software is using a Performance Route Processor, the following command can be run:RP/0/RSP0/CPU0:ASR9006-D#show inventory all | include Route Switch Processor
Thu May 3 18:50:46.129 UTC
NAME: "module 0/RSP0/CPU0", DESCR: "ASR9K Route Switch Processor with 440G/slot Fabric and 6GB"
NAME: "module 0/RSP1/CPU0", DESCR: "ASR9K Route Switch Processor with 440G/slot Fabric and 6GB"
RP/0/RP0/CPU0:CRS-G#show inventory all | include Performance Route Processor
Wed May 2 14:49:06.994 EDT
NAME: "0/RP0/*", DESCR: "Cisco CRS Series 8 Slots 12 GB Performance Route Processor"
NAME: "0/RP1/*", DESCR: "Cisco CRS Series 8 Slots 12 GB Performance Route Processor"
Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by this vulnerability, including other Route Processors such as the Cisco CRS-1 Distributed Route Processor (DRP), RP-A or RP-B.
Details
Vulnerable software versions must be combined with one of the following Route Processors in order to be affected:
| Platform |
Route Processor Part ID |
| ASR 9000 |
A9K-RSP440-SE |
| ASR 9000 |
A9K-RSP440-TR |
| ASR 9000 | A9K-RSP-4G |
| ASR 9000 | A9K-RSP-8G |
| CRS | CRS-8-PRP-6G |
| CRS | CRS-8-PRP-12G |
| CRS | CRS-16-PRP-6G |
| CRS | CRS-16-PRP-12G |
This vulnerability has been documented in Cisco Bug IDs CSCty94537 and CSCua63591 (ASR 9000) and CSCtz62593 (CRS) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2012-2488.
Cisco IOS XR Software Route Processor Denial of Service Vulnerability
Cisco IOS XR Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.The vulnerability is due to improper processing of crafted packets by Cisco 9000 Series Aggregation Services Routers (ASR) Route Switch Processor (RSP-4G or RSP-8G), Route Switch Processor 440 (RSP440), or Carrier Routing System (CRS) Performance Route Processor. An attacker could exploit this vulnerability by sending a crafted packet to a vulnerable system; this vulnerability cannot be triggered by IP traffic transiting a vulnerable device. An exploit could allow the attacker to cause the packets originating on the Route Processor CPU to stop transmitting to the fabric, resulting in a DoS condition.
Vulnerability Scoring Details
Cisco has provided the score for the vulnerability 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 the 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 compute the environmental impact for individual networks at:
http://intellishield.cisco.com/security/alertmanager/cvss
|
CSCty94537, CSCua63591, CSCtz62593 - Cisco IOS XR Software Route Processor Denial of Service Vulnerability Calculate the environmental score of CSCty94537, CSCua63591, and CSCtz62593 |
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|---|---|---|---|---|---|---|
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CVSS Base Score - 7.8 |
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|
Access Vector |
Access Complexity |
Authentication |
Confidentiality Impact |
Integrity Impact |
Availability Impact |
|
|
Network |
Low |
None |
None |
None |
Complete |
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CVSS Temporal Score - 6.4 |
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Exploitability |
Remediation Level |
Report Confidence |
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Functional |
Official-Fix |
Confirmed |
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Impact
Software Versions and Fixes
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.
For IOS XR running on Cisco ASR 9000 Series RSP440, the vulnerability is present in software version 4.2.0 and is fixed with SMU name 4.2.0_asr9k-px_REC_SMUS_2012-05-15.tar.
For IOS XR running on Cisco ASR 9000 Series RSP-4G or RSP-8G, the vulnerability is present in versions prior to 4.2.0. The following SMUs for ASR 9000 Series RSP-4G or RSP-8G devices correct this vulnerability:
| IOS XR Version |
SMU ID |
SMU Name |
| 4.0.1 | AA06294 |
asr9k-p-4.0.1.CSCua63591 |
| 4.0.3 | AA06313 | asr9k-p-4.0.3.CSCua63591 |
| 4.1.0 | AA06306 | asr9k-p-4.1.0.CSCua63591 |
| 4.1.1 | AA06308 | asr9k-p-4.1.1.CSCua63591 |
| 4.1.2 | AA06305 | asr9k-p-4.1.2.CSCua63591 |
For IOS XR running on CRS Performance Route Processor, the vulnerability is present in versions 4.0.3, 4.0.4, 4.1.0, 4.1.1, 4.1.2, and 4.2.0. The following SMUs for CRS series devices correct this vulnerability:
| IOS XR Version |
SMU ID |
SMU Name |
| 4.0.3 |
AA06162 | hfr-px-4.0.3.CSCtz62593 |
| 4.0.4 | AA06161 | hfr-px-4.0.4.CSCtz62593 |
| 4.1.0 | AA06163 | hfr-px-4.1.0.CSCtz62593 |
| 4.1.1 | AA06164 | hfr-px-4.1.1.CSCtz62593 |
| 4.1.2 | AA06165 | hfr-px-4.1.2.CSCtz62593 |
| 4.2.0 | AA06166 | hfr-px-4.2.0.CSCtz62593 |
This vulnerability will be fixed in IOS XR version 4.2.1 for both Cisco ASR 9000 series devices and CRS series devices.
Workarounds
Obtaining Fixed Software
Cisco has released free software updates that address the vulnerability described in this advisory. Prior to deploying software, customers are advised to consult their maintenance provider or check the software for feature set compatibility and known issues that are 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.
Customers with Service Contracts
Customers Using Third-Party Support Organizations
Customers with Cisco products that 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 organization for assistance with the appropriate course of action.
The effectiveness of any workaround or fix depends on specific customer situations, such as product mix, network topology, traffic behavior, and organizational mission. Because of the variety of affected products and releases, customers should consult their service providers or support organizations to ensure that any applied workaround or fix is the most appropriate in the intended network before it is deployed.
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):
- +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 the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade. Customers without service contracts should request free upgrades through the TAC.
Refer to Cisco Worldwide Contacts at http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including localized telephone numbers, instructions, and e-mail addresses for support in various languages.
Exploitation and Public Announcements
This vulnerability was discovered while diagnosing issues encountered in customer networks.
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 Security Intelligence Operations at the following link:
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120530-iosxr
Additionally, a text version of this advisory is clear signed with the Cisco PSIRT PGP key and circulated among the following e-mail addresses:
- 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
Future updates of this advisory, if any, will reside on Cisco.com but may not be announced on mailing lists. Users can monitor this advisory's URL for any updates.
Revision History
| Revision 2.1 | 2012-August-23 | Doc updated to correct first published date |
| Revision 2.0 | 2012-August-15 | Updated affected platforms to include RSP-4G and RSP-8G on ASR 9000 Series, prior to IOS XR 4.2.0 |
| Revision 1.1 | 2012-May-31 | Updated Software Versions and Fixes to clarify SMU names and to provide links to relevant Software Downloads pages |
| Revision 1.0 | 2012-May-30 | Initial public release |
