A vulnerability in the Network Address Translation (NAT) feature of Cisco IOS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper translation of IP version 4 (IPv4) packets. Cisco has released software updates that address this vulnerability. This advisory is available at the following link: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20140924-nat Note: The September 24, 2014, Cisco IOS Software Security Advisory bundled publication includes six Cisco Security Advisories. All advisories address vulnerabilities in Cisco IOS Software. Individual publication links are in Cisco Event Response: Semiannual Cisco IOS Software Security Advisory Bundled Publication at the following link: http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep14.html
http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep14.html
If no interfaces are listed on the output of the show ip nat statistics command, NAT may still be active on the device through the NAT Virtual Interface feature. To determine whether NAT is active through this feature, issue the show ip nat nvi statistics command. If NAT is active, the "NAT Enabled interfaces" section will include at least one interface. The following example shows a device where NAT is active:Router#show ip nat statistics Total active translations: 0 (0 static, 0 dynamic; 0 extended) Peak translations: 10, occurred 00:24:01 ago Outside interfaces: FastEthernet0/0 Inside interfaces: FastEthernet0/1 Hits: 134280 Misses: 0 CEF Translated packets: 134270, CEF Punted packets: 10 Expired translations: 11 Dynamic mappings: -- Inside Source [Id: 1] access-list NET-192.168.20.0_24 pool POOL-NET-192.168.1.0_24 refcount 0 pool POOL-NET-192.168.1.0_24: netmask 255.255.255.0 start 192.168.1.120 end 192.168.1.128 type generic, total addresses 9, allocated 0 (0%), misses 0 Total doors: 0 Appl doors: 0 Normal doors: 0 Queued Packets: 0 Router#
Router#show ip nat nvi statistics Total active translations: 1 (0 static, 1 dynamic; 1 extended) NAT Enabled interfaces: FastEthernet0/0, FastEthernet0/1 Hits: 81373 Misses: 3 CEF Translated packets: 44371, CEF Punted packets: 8 Expired translations: 3 Dynamic mappings: -- Source [Id: 1] access-list NET-192.168.20.0_24 pool POOL-NET-192.168.1.0_24 refcount 1 pool POOL-NET-192.168.1.0_24: netmask 255.255.255.0 start 192.168.1.120 end 192.168.1.128 type generic, total addresses 9, allocated 1 (11%), misses 0 Router#
Router#show running-config | include ip nat service allow-multipart ip nat service allow-multipart Router#
To determine the Cisco IOS Software release that is running on a Cisco product, administrators can log in to the device and issue the show version command to display the system banner. The system banner confirms that the device is running Cisco IOS Software by displaying text similar to "Cisco Internetwork Operating System Software" or "Cisco IOS Software." The image name displays in parentheses, followed by "Version" and the Cisco IOS Software release name. Other Cisco devices do not have the show version command or may provide different output.
The following example identifies a Cisco product that is running Cisco IOS Software Release 15.2(4)M5 with an installed image name of C3900-UNIVERSALK9-M:
Router> show version
Cisco IOS Software, C3900 Software (C3900-UNIVERSALK9-M), 15.2(4)M5, RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2013 by Cisco Systems, Inc.
Compiled Fri 13-Sep-13 16:44 by prod_rel_team!--- output truncated
Additional information about Cisco IOS Software release naming conventions is available in White Paper: Cisco IOS and NX-OS Software Reference Guide.
Cisco has provided a tool to help customers determine their exposure to vulnerabilities in Cisco IOS Software. The Cisco IOS Software Checker allows customers to perform the following tasks:
The tool will identify any Cisco Security Advisories that impact a queried software release and the earliest release that corrects all vulnerabilities in each Cisco Security Advisory ("First Fixed"). If applicable, the tool will also return the earliest possible release that corrects all vulnerabilities in all displayed advisories ("Combined First Fixed"). Please visit the Cisco IOS Software Checker or simply enter a Cisco IOS Software release in the following field to determine whether it is affected by any of the advisories in this bundled publication.
(Example entry: 15.1(4)M2)
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.
Revision 1.0 | 2014-September-24 | Initial public release. |
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