Cisco Security Advisory-
Cisco 9000 Series Aggregation Services Routers (ASR) running Cisco IOS XR Software version 4.1.0 contain a vulnerability that may cause a network processor in a line card to lock up while processing an IP version 4 (IPv4) packet. As a consequence of the network processor lockup, the line card that is processing the offending packet will automatically reload.
Cisco has released a free software maintenance upgrade (SMU) to address this vulnerability.
There are no workarounds for this vulnerability.
This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110720-asr9k.
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Vulnerable Products
This vulnerability affects the following Cisco ASR 9000 Series devices when they are running Cisco IOS XR Software version 4.1.0 without the SMU asr9k-p-4.1.0.CSCtr26695.tar installed:
- Cisco ASR 9006 router
- Cisco ASR 9010 router
To determine the software running on a Cisco ASR 9000 Series device, log in to the device and issue the show version brief command to display the system banner. The system banner confirms that the device is running Cisco IOS XR Software by displaying text similar to Cisco IOS XR Software. The software version is displayed after the text Cisco IOS XR Software.
The following example identifies a Cisco ASR 9010 that is running Cisco IOS XR Software Release 4.1.0:
RP/0/0/CPU0:Router#show version brief Fri Jul 8 18:54:39.222 CEST Cisco IOS XR Software, Version 4.1.0[Default] Copyright (c) 2011 by Cisco Systems, Inc. ROM: System Bootstrap, Version 1.05(20101118:025914) [ASR9K ROMMON], Router uptime is 9 weeks, 1 day, 5 hours, 53 minutes System image file is "bootflash:disk0/asr9k-os-mbi-4.1.0/mbiasr9k-rp.vm" cisco ASR9K Series (MPC8641D) processor with 4194304K bytes of memory. MPC8641D processor at 1333MHz, Revision 2.2 ASR-9010-CHASSIS 4 Management Ethernet 8 WANPHY controller(s) 8 TenGigE 8 DWDM controller(s) 40 GigabitEthernet 4 SONET/SDH 2 Packet over SONET/SDH 1 MgmtMultilink 219k bytes of non-volatile configuration memory. 975M bytes of compact flash card. 33994M bytes of hard disk. 1605616k bytes of disk0: (Sector size 512 bytes). 1605616k bytes of disk1: (Sector size 512 bytes).
To determine which SMUs are active on the device, issue the show install active summary command. This command will return a list of all SMUs installed, as shown in the following example:
RP/0/0/CPU0:Router#show install active summary Fri Jul 8 19:02:15.887 CEST Active Packages: disk0:asr9k-doc-p-4.1.0 disk0:asr9k-mini-p-4.1.0 disk0:asr9k-k9sec-p-4.1.0 disk0:asr9k-video-p-4.1.0Note: The preceding output shows a device without the SMU asr9k-p-4.1.0.CSCtr26695.tar installed. Also note that Cisco IOS XR Software can include multiple SMUs and the output may differ from the preceding example.
Products Confirmed Not Vulnerable
The following products are confirmed not vulnerable:
- Cisco Carrier Routing System (CRS) running any version of Cisco IOS XR Software
- Cisco XR 12000 Series Routers running any version of Cisco IOS XR Software
- Cisco 12000 Series Routers running any version of Cisco IOS Software
- Cisco IOS Software
- Cisco IOS XE Software
- Cisco NX-OS Software
- Cisco ASR 1000 and 5000 Series routers running any version of software
- Cisco ASR 9000 Series routers running any version of Cisco IOS XR Software other than 4.1.0
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Cisco ASR 9000 Series routers running Cisco IOS XR Software version
4.1.0 and with the SMU asr9k-p-4.1.0.CSCtr26695.tar
installed
To determine which SMUs are active on the device, issue the show install active summary command. This will return a list of all SMUs installed:
Note: The preceding output shows a device with the SMU asr9k-p-4.1.0.CSCtr26695.tar installed (in bold). Also note that Cisco IOS XR Software can include multiple SMUs and the output may differ from the preceding example.RP/0/0/CPU0:Router#show install active summary Fri Jul 8 19:02:15.887 CEST Active Packages: disk0:asr9k-p-4.1.0.CSCtr26695-1.0.0 disk0:asr9k-p-4.1.0.CSCto96804-1.0.0 disk0:asr9k-p-4.1.0.CSCto95435-1.0.0 disk0:asr9k-doc-p-4.1.0 disk0:asr9k-mini-p-4.1.0 disk0:asr9k-k9sec-p-4.1.0 disk0:asr9k-video-p-4.1.0
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Cisco ASR 9000 Series routers are designed to provide carrier-class reliability using the Cisco IOS XR Software modular operating system, offering service and application-level intelligence focused on optimized video delivery and mobile aggregation in Carrier Ethernet Services networks.
Cisco IOS XR Software is a distributed operating system designed for continuous system operation combined with service flexibility and high performance.
Cisco ASR 9000 Series devices running Cisco IOS XR Software version 4.1.0 contain a vulnerability that may cause a network processor in a line card to lock up while processing an IPv4 packet. As a consequence of the network processor lockup, the line card that is processing the offending packet will automatically reload.
This vulnerability can be triggered only by IPv4 packets. If only IP version 6 (IPv6) is in use, the device is not vulnerable.
Both transit IPv4 packets and IPv4 packets directed to the device itself may trigger this vulnerability.
One or both the following messages may appear in the system log:
- PLATFORM-DIAGS-3-PUNT_FABRIC_DATA_PATH_FAILED
- PLATFORM-DIAGS-0-LC_NP_LOOPBACK_FAILED
This vulnerability is documented as CSCtr26695 (registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2011-2549
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There are no workarounds for this vulnerability.
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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.
Each row of the Cisco IOS XR Software table (below) names a Cisco IOS XR Software release train. If a given release train is vulnerable, then the earliest possible releases that contain the fix, if available at the time of Advisory, are listed in the "First Fixed Release" column of the table.
Major Release
Availability of Repaired Releases
SMU ID
SMU Name
First Fixed Release
3.2.X through 4.0.X
Not affected
4.1.0
AA05118
asr9k-p-4.1.0.CSCtr26695.tar
4.1.1
Note: At the time of this advisory, Release 4.1.1 is expected to be available on July 29, 2011.
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The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.
This vulnerability was found during the resolution of multiple customer service requests.
We would like to thank the Internet Measurement Group from the University of Washington for their help and support on troubleshooting this issue.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Show LessRevision 1.0
2011-July-20
Initial public release
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