A vulnerability in the multicast DNS (mDNS) gateway function of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to reload the vulnerable device. The vulnerability is due to improper validation of mDNS packets. An attacker could exploit this vulnerability by sending malformed IP version 4 (IPv4) or IP version 6 (IPv6) packets on UDP port 5353. An exploit could allow the attacker to cause a denial of service (DoS) condition. 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-20150325-mdnswo Note: The March 25, 2015, Cisco IOS & XE Software Security Advisory bundled publication includes seven Cisco Security Advisories. The advisories address vulnerabilities in Cisco IOS Software and Cisco IOS XE Software. Individual publication links are in Cisco Event Response: Semiannual Cisco IOS & XE Software Security Advisory Bundled Publication at the following link: http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_mar15.html
http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_mar15.html
Router#show ip socket Proto Remote Port Local Port In Out Stat TTY OutputIF 17 --listen-- 192.168.0.1 67 0 0 1 0 17 --listen-- 192.168.0.1 68 0 0 1 0 17 --listen-- 224.0.0.251 5353 0 0 1 0 Router# Router#sho udp Proto Remote Port Local Port In Out Stat TTY OutputIF 17 224.0.0.251 5353 --any-- 5353 0 0 1000021 0 17(v6) FF02::FB 5353 --any-- 5353 0 0 1020021 0 Router# Router#sho control-plane host open-ports Active internet connections (servers and established) Prot Local Address Foreign Address Service State tcp *:22 *:0 SSH-Server LISTEN tcp *:23 *:0 Telnet LISTEN udp *:5353 224.0.0.251:0 IOS host service LISTEN 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 the Cisco IOS Software release number and 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), Version 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.
!--- !--- Deny IPv4 mDNS traffic to a device !--- access-list 150 deny udp any any eq 5353 !--- Permit/deny all other Layer 3 and Layer 4 IPv4 traffic in !--- accordance with existing security policies and !--- configurations. Permit all other traffic to transit the !--- device. access-list 150 permit ip any any !--- !--- Deny IPv6 mDNS traffic to a device !---
ipv6 access-list v6_list deny udp any any eq 5353 !--- Permit/deny all other Layer 3 and Layer 4 IPv6 traffic in !--- accordance with existing security policies and !--- configurations. Permit all other traffic to transit the !--- device. permit ipv6 any any !--- Apply access list to all interfaces (only one example !--- shown) interface fastEthernet 2/0 ip access-group 150 in ipv6 traffic-filter v6_list in
!--- !--- Match IPv4 mDNS traffic with permit statement !--- access-list 150 permit udp any any eq 5353 !--- Permit (police or drop)/Deny (allow) all other Layer 3 and !--- Layer 4 IPv4 traffic in accordance with existing security policies !--- and configurations for traffic that is authorized to be sent !--- to infrastructure devices !--- access-list 150 deny ip any any !--- Create a Class-Map for traffic to be policed by !--- the CoPP feature !--- class-map match-all drop-udp-class match access-group 150 !--- Create a policy map that will be applied to the !--- control plane of the device. policy-map drop-udp-traffic class drop-udp-class drop !--- Apply the policy map to the !--- control plane of the device control-plane service-policy input drop-udp-traffic
policy-map drop-udp-traffic class drop-udp-class police 32000 1500 1500 conform-action drop exceed-action drop
Cisco provides 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 identifies 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 also returns the earliest possible release that corrects all vulnerabilities in all displayed advisories ("Combined First Fixed"). Please visit the Cisco IOS Software Checker or enter a Cisco IOS Software release in the following field to determine whether the release is affected by any published Cisco IOS Software advisory.
(Example entry: 15.1(4)M2)
| Cisco IOS XE Software Release | First Fixed Release for this Advisory | First Fixed Release for All Advisories in the March 2015 Cisco IOS Software Security Advisory Bundled Publication |
|---|---|---|
| 2.5.x | Not vulnerable |
Vulnerable; migrate to 3.12.3S or later. |
| 2.6.x | Not vulnerable | Vulnerable; migrate to 3.12.3S or later. |
| 3.1.xS | Not vulnerable | Vulnerable; migrate to 3.12.3S or later. |
| 3.1.xSG | Not vulnerable | Not vulnerable |
| 3.2.xS | Not vulnerable | Vulnerable; migrate to 3.12.3S or later. |
| 3.2.xSE | Not vulnerable | Vulnerable; migrate to 3.7.1E or later. |
| 3.2.xSG | Not vulnerable | Not vulnerable |
| 3.2.xXO | Not vulnerable | Not vulnerable |
| 3.2.xSQ | Not vulnerable | Not vulnerable |
| 3.3.xS | Not vulnerable | Vulnerable; migrate to 3.12.3S or later. |
| 3.3.xSE | Not vulnerable | Vulnerable; migrate to 3.7.1E or later. |
| 3.3.xSG | Not vulnerable | Vulnerable; migrate to 3.7.1E or later. |
| 3.3.xXO | Not vulnerable | Vulnerable; migrate to 3.7.1E or later. |
| 3.3.xSQ | Not vulnerable | Not vulnerable |
| 3.4.xS | Not vulnerable | Vulnerable; migrate to 3.12.3S or later. |
| 3.4.xSG | Not vulnerable | Vulnerable; migrate to 3.7.1E or later. |
| 3.4.xSQ | Not vulnerable | Not vulnerable |
| 3.5.xS | Not vulnerable | Vulnerable; migrate to 3.12.3S or later. |
| 3.5.xE | Not vulnerable | Vulnerable; migrate to 3.7.1E or later. |
| 3.6.xS | Not vulnerable | Vulnerable; migrate to 3.12.3S or later. |
| 3.6.xE | 3.6.1E | 3.6.2E |
| 3.7.xS | Not vulnerable | Vulnerable; migrate to 3.12.3S or later. |
| 3.7.xE | Not vulnerable | 3.7.1E |
| 3.8.xS | Not vulnerable |
Vulnerable; migrate to 3.12.3S or later. |
| 3.9.xS | Vulnerable; migrate to 3.10.4S or later. | Vulnerable; migrate to 3.12.3S or later. |
| 3.10.xS | 3.10.4S |
Vulnerable; migrate to 3.12.3S or later. |
| 3.11.xS | 3.11.3S |
Vulnerable; migrate to 3.12.3S or later. |
| 3.12.xS | 3.12.2S |
Vulnerable; migrate to 3.12.3S or later. |
| 3.13.xS | 3.13.1S |
3.13.2S |
| 3.14.xS |
Not vulnerable |
Not vulnerable |
| 3.15.xS |
Not vulnerable | Not vulnerable |
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.
| Version | Description | Section | Status | Date |
|---|---|---|---|---|
| 1.4 | Updated Cisco IOS Checker Software Checker form to query all previously published Cisco IOS Software Security Advisories. | 2016-January-14 | ||
| 1.3 | Added Cisco IOS XE 3.6.0E as an affected release. Added 3.6.2E as a first fixed for bundle wide for 3.6E since it became available after the bundle was published. | 2015-September-25 |
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