Cisco Security Advisory-
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 https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110525-iosxrspa.
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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.
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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.
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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
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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.
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
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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 discovered when handling customer support calls.
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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-May-25
Initial public release.
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