Cisco Security Advisory

Cisco IOS User Datagram Protocol Delivery Issue For IPv4/IPv6 Dual-stack Routers

High

Advisory ID:

cisco-sa-20080326-IPv4IPv6

First Published:

2008 March 26 16:00 GMT

Version 1.5:

Final

Workarounds:

See below

Cisco Bug IDs:

CSCse56501

CVE-2008-1153

CWE-399

CVSS Score:

Base 7.8, Temporal 6.4

CVE-2008-1153

CWE-399

Summary

A device running Cisco IOS software that has Internet Protocol version 6 (IPv6) enabled may be subject to a denial of service (DoS) attack. For the device to be affected by this vulnerability the device also has to have certain Internet Protocol version 4 (IPv4) User Datagram Protocol (UDP) services enabled. To exploit this vulnerability an offending IPv6 packet must be targeted to the device. Packets that are routed throughout the router can not trigger this vulnerability. Successful exploitation will prevent the interface from receiving any additional traffic. The only exception is Resource Reservation Protocol (RSVP) service, which if exploited, will cause the device to crash. Only the interface on which the vulnerability was exploited will be affected.

Cisco is providing fixed software to address this issue. There are workarounds available to mitigate the effects of the vulnerability.

This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080326-IPv4IPv6.

Note: The March 26, 2008 publication includes five Security Advisories. The Advisories all affect Cisco's Internetwork Operating System (IOS). Each Advisory lists the releases that correct the vulnerability described in the Advisory, and the Advisories also detail the releases that correct the vulnerabilities in all five Advisories.

Individual publication links are listed below:
- Cisco IOS Virtual Private Dial-up Network Denial of Service Vulnerability
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080326-pptp
- Multiple DLSw Denial of Service Vulnerabilities in Cisco IOS
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080326-dlsw
- Cisco IOS User Datagram Protocol Delivery Issue For IPv4/IPv6 Dual-stack Routers
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080326-IPv4IPv6
- Vulnerability in Cisco IOS with OSPF, MPLS VPN, and Supervisor 32, Supervisor 720, or Route Switch Processor 720
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080326-queue
- Cisco IOS Multicast Virtual Private Network (MVPN) Data Leak
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080326-mvpn

Affected Products

Vulnerable Products

Only Cisco IOS software releases that have IPv6 enabled are affected by this vulnerability. In order to be vulnerable both support for IPv6 protocol and IPv4 UDP-based services must be enabled on the device. The IPv6 is not enabled by default in Cisco IOS software.

To determine the software running on a Cisco IOS product, log in to the device and issue the show version command to display the system banner. Cisco IOS software will identify itself as "Internetwork Operating System Software" or simply "IOS." On the next line of output, the image name will be displayed between parentheses, followed by "Version" and the Cisco IOS software release name. Other Cisco devices will not have the show version command, or will give different output.

The following example shows output from a device running a Cisco IOS image:

Router>show version Cisco IOS Software, 1841 Software (C1841-ADVSECURITYK9-M), Version 12.4(15)T2, RELEASE SOFTWARE (fc7) Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2008 by Cisco Systems, Inc. Compiled Thu 17-Jan-08 23:12 by prod_rel_team

Additional information about Cisco IOS software release naming is available at the following link: http://www.cisco.com/warp/public/620/1.html.

In order for an interface to be vulnerable two conditions must be satisfied:

An interface must have IPv6 enabled.

One or more of the following IPv4 UDP-based services must be enabled:
TACACS - port 49
Domain Name System (DNS) server - port 53
Resource Reservation Protocol (RSVP) - port 1698
Layer Two Forwarding (L2F)/Layer Two Tunnel Protocol (L2TP) - port 1701
IP SLA Responder - port 1967
Media Gateway Control Protocol (MGCP) - port 2427
Session Initiation Protocol (SIP) - port 5060

No other IPv4 UDP-based services are known to be affected.

How To Verify If IPv6 Is Enabled

IPv6 protocol is enabled on an interface if either or both of the following configuration lines are present in the configuration:

Router#show running-config interface FastEthernet0/1 ipv6 address 2001:0DB8:C18:1::/64 eui-64

Router#show running-config interface FastEthernet0/1 ipv6 enabled

If any of the interfaces contain either or both of the ipv6 lines then IPv6 is enabled on that particular interface.

How To Verify If IPv4 UDP-based Services Are Enabled

To determine whether device is affected or not, use the show ip sockets command to display all UDP ports device is listening to. In some newer IOS releases the command show ip sockets is obsoleted, and the alternate command show udp can be used instead. The output is identical to the show ip sockets command.

The device is vulnerable if the Local Port column (fifth from the left) in the output of show ip sockets contains any of the port numbers listed in the example below.

Router#show ip sockets Proto Remote Port Local Port In Out Stat TTY OutputIF 17 192.168.100.1 49 192.168.100.2 49 0 0 11 0 17 0.0.0.0 0 192.168.100.2 53 0 0 211 0 17 --listen-- 192.168.100.2 1698 0 0 1 0 17 192.168.100.1 1701 192.168.100.2 1701 1 0 1021 0 17 0.0.0.0 0 192.168.100.2 1967 0 0 211 0 17 0.0.0.0 0 --any-- 2427 0 0 211 0 17 0.0.0.0 0 --any-- 5060 0 0 211 0

Products Confirmed Not Vulnerable

No other Cisco products are currently known to be affected by this vulnerability.

Any device running Cisco IOS without IPv6 enabled is not vulnerable. Cisco IOS XR and Cisco PIX/ASA are not affected.

Details

To exploit this vulnerability an offending IPv6 packet must be targeted to the device. Packets that are routed throughout the router can not trigger this vulnerability. Successful exploitation of the vulnerability may result in one of the following two conditions:
1. The device will crash if RSVP service is configured on the interface.
2. Any other affected IPv4 UDP-based service will prevent the interface from receiving additional traffic. Only the interface on which the vulnerability is exploited will be affected.
This vulnerability is independent of the interface media type. A blocked interface will immediately stop receiving any subsequent packets destined to the device itself until it is unblocked. It is possible to unblock the interface using methods other than a device reload. These methods are described in the Workarounds section. All other interfaces are unaffected and will continue receiving and transmitting packets.

Blocked interface may allow transit traffic to flow for a period of time. Transit traffic may continue to flow until either the respective routing entry or Address Resolution Protocol (ARP) entry expires, whichever event occurs first. Depending on the circumstances the transit traffic can stop flowing through the blocked interface within a few seconds or continue up to four hours (which is the ARP cache default lifetime). After that no further transit traffic will flow through the blocked interface.

No other IPv4 UDP-based services are known to be affected by this vulnerability.

This vulnerability is documented in Cisco Bug ID CSCse56501, and has been assigned the Common Vulnerabilities and Exposures (CVE) ID CVE-2008-1153.

Identification Of Vulnerability Exploitation

The show interfaces command can be used to view the input queue size to identify a blocked input interface. A device under attack, but not yet blocked will show the Input queue size increasing without a subsequent decrease. If the current size (in this case, 76) is larger than the maximum size (75), the input queue is blocked. The value of 75 is the default value and it can be changed using the interface command hold-queue X in .
Router#show interfaces FastEthernet 0/1 | include queue Input queue: 76/75/0/0 (size/max/drops/flushes); Total output drops: 0 Output queue: 0/40 (size/max)
The example above shows that the interface FastEthernet0/1 is blocked.

The show ip sockets command can be used to determine which protocol blocks the interface. If In column (sixth from the left) of the output contains any other number than zero (0) that is an indication that packets of that particular protocol are blocking, or starting to block, the interface. The following example shows DNS packets that are beginning to fill the input queue of the interface. The interface is not completely blocked because only 13 packets are in the input queue.
Router#show ip sockets Proto Remote Port Local Port In Out Stat TTY OutputIF 17 192.168.100.1 49 192.168.100.2 49 0 0 11 0 17 0.0.0.0 0 192.168.100.2 53 13 0 211 0 17 --listen-- 192.168.100.2 1698 0 0 1 0 17 192.168.100.1 1701 192.168.100.2 1701 1 0 1021 0 17 0.0.0.0 0 192.168.100.2 1967 0 0 211 0 17 0.0.0.0 0 --any-- 2427 0 0 211 0 17 0.0.0.0 0 --any-- 5060 0 0 211 0
The output of the show ip sockets command does not provide information on interfaces. It is possible that packets from multiple protocols may be blocking a single interface. The output of the command must be interpreted with the device's configuration to establish the affected port.

Additional methods that can be used to detect blocked interfaces are described in "Cisco Applied Mitigation Bulletin: User Datagram Protocol Delivery Issue For IPv4/IPv6 Dual-Stack Routers" document available at https://sec.cloudapps.cisco.com/security/center/content/CiscoAppliedMitigationBulletin/cisco-amb-20080326-IPv4IPv6. The method utilizes Embedded Event Manager (EEM) and Applets or an EEM Script.

Workarounds

Interface Access Control List

By deploying an IPv6 Access Control List (ACL) it is possible to prevent offending IPv6 packets reaching vulnerable UDP services. The ACL in the following example will block all IPv6 traffic from reaching vulnerable services.

Router(config)#ipv6 access-list protect_IPv4_services
Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq tacacs
Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq domain
Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq 1698 
Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq 1701 
Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq 1967 
Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq 2427 
Router(config-ipv6-acl)#deny udp any 2001:DB8:1:128::/64 eq 5060

!--- Deny access to link-local address space

Router(config-ipv6-acl)#deny udp any FE80::/10 eq tacacs 
Router(config-ipv6-acl)#deny udp any FE80::/10 eq domain 
Router(config-ipv6-acl)#deny udp any FE80::/10 eq 1698 
Router(config-ipv6-acl)#deny udp any FE80::/10 eq 1701 
Router(config-ipv6-acl)#deny udp any FE80::/10 eq 1967 
Router(config-ipv6-acl)#deny udp any FE80::/10 eq 2427 
Router(config-ipv6-acl)#deny udp any FE80::/10 eq 5060 

!--- Permit/deny all other Layer 3 and Layer 4 traffic       
!--- in accordance with existing security policies and configurations                     
!
!--- Allow all other IPv6 traffic

Router(config-ipv6-acl)#permit ipv6 any 2001:db8:1:128::/64

!
!

Router(config)#interface FastEthernet0/1
Router(config-if)#ipv6 traffic-filter protect_IPv4_services in

Receive Access Control List

Receive Access Lists (rACL) are a feature available on the following hardware models: Cisco 12000 Series, Cisco 7500 Series and Cisco 10720 Router.

By deploying rACL it is possible to prevent offending IPv6 packets from reaching vulnerable UDP services. The rACL in the following example will block all IPv6 traffic from reaching vulnerable services.

Router(config)#ipv6 access-list rACL
Router(config-ipv6-acl)#deny udp any any eq tacacs
Router(config-ipv6-acl)#deny udp any any eq domain
Router(config-ipv6-acl)#deny udp any any eq 1698
Router(config-ipv6-acl)#deny udp any any eq 1701
Router(config-ipv6-acl)#deny udp any any eq 1967
Router(config-ipv6-acl)#deny udp any any eq 2427
Router(config-ipv6-acl)#deny udp any any eq 5060

!--- Allow all other IPv6 traffic

Router(config-ipv6-acl)#permit ipv6 any any
Router(config)#ipv6 receive access-list rACL

Additional Mitigation Techniques

Additional mitigation techniques that can be deployed on Cisco devices within the network are available in the Cisco Applied Mitigation Bulletin companion document for this advisory:

https://sec.cloudapps.cisco.com/security/center/content/CiscoAppliedMitigationBulletin/cisco-amb-20080326-IPv4IPv6

Fixed Software

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 software table (below) names a Cisco IOS release train. If a given release train is vulnerable, then the earliest possible releases that contain the fix (along with the anticipated date of availability for each, if applicable) are listed in the "First Fixed Release" column of the table. The "Recommended Release" column indicates the releases which have fixes for all the published vulnerabilities at the time of this Advisory. A device running a release in the given train that is earlier than the release in a specific column (less than the First Fixed Release) is known to be vulnerable. Cisco recommends upgrading to a release equal to or later than the release in the "Recommended Releases" column of the table.

Major Release	Availability of Repaired Releases
Affected 12.0-Based Releases	First Fixed Release	Recommended Release
12.0	Not Vulnerable
12.0DA	Not Vulnerable
12.0DB	Not Vulnerable
12.0DC	Not Vulnerable
12.0S	Vulnerable; contact TAC
12.0SC	Not Vulnerable
12.0SL	Not Vulnerable
12.0SP	Not Vulnerable
12.0ST	Not Vulnerable
12.0SX	Not Vulnerable
12.0SY	Vulnerable; contact TAC
12.0SZ	Vulnerable; contact TAC
12.0T	Not Vulnerable
12.0W	Not Vulnerable
12.0WC	Not Vulnerable
12.0WT	Not Vulnerable
12.0XA	Not Vulnerable
12.0XB	Not Vulnerable
12.0XC	Not Vulnerable
12.0XD	Not Vulnerable
12.0XE	Not Vulnerable
12.0XF	Not Vulnerable
12.0XG	Not Vulnerable
12.0XH	Not Vulnerable
12.0XI	Not Vulnerable
12.0XJ	Not Vulnerable
12.0XK	Not Vulnerable
12.0XL	Not Vulnerable
12.0XM	Not Vulnerable
12.0XN	Not Vulnerable
12.0XQ	Not Vulnerable
12.0XR	Not Vulnerable
12.0XS	Not Vulnerable
12.0XV	Not Vulnerable
12.0XW	Not Vulnerable
Affected 12.1-Based Releases	First Fixed Release	Recommended Release
12.1	Not Vulnerable
12.1AA	Not Vulnerable
12.1AX	Not Vulnerable
12.1AY	Not Vulnerable
12.1AZ	Not Vulnerable
12.1CX	Not Vulnerable
12.1DA	Not Vulnerable
12.1DB	Not Vulnerable
12.1DC	Not Vulnerable
12.1E	Not Vulnerable
12.1EA	Not Vulnerable
12.1EB	Not Vulnerable
12.1EC	Not Vulnerable
12.1EO	Not Vulnerable
12.1EU	Not Vulnerable
12.1EV	Not Vulnerable
12.1EW	Not Vulnerable
12.1EX	Not Vulnerable
12.1EY	Not Vulnerable
12.1EZ	Not Vulnerable
12.1GA	Not Vulnerable
12.1GB	Not Vulnerable
12.1T	Not Vulnerable
12.1XA	Not Vulnerable
12.1XB	Not Vulnerable
12.1XC	Not Vulnerable
12.1XD	Not Vulnerable
12.1XE	Not Vulnerable
12.1XF	Not Vulnerable
12.1XG	Not Vulnerable
12.1XH	Not Vulnerable
12.1XI	Not Vulnerable
12.1XJ	Not Vulnerable
12.1XK	Not Vulnerable
12.1XL	Not Vulnerable
12.1XM	Not Vulnerable
12.1XN	Not Vulnerable
12.1XO	Not Vulnerable
12.1XP	Not Vulnerable
12.1XQ	Not Vulnerable
12.1XR	Not Vulnerable
12.1XS	Not Vulnerable
12.1XT	Not Vulnerable
12.1XU	Vulnerable; first fixed in 12.3	12.3(26)
12.1XV	Vulnerable; first fixed in 12.3	12.3(26)
12.1XW	Not Vulnerable
12.1XX	Not Vulnerable
12.1XY	Not Vulnerable
12.1XZ	Not Vulnerable
12.1YA	Not Vulnerable
12.1YB	Vulnerable; first fixed in 12.3	12.3(26)
12.1YC	Vulnerable; first fixed in 12.3	12.3(26)
12.1YD	Vulnerable; first fixed in 12.3	12.3(26)
12.1YE	Releases prior to 12.1(5)YE6 are vulnerable, release 12.1(5)YE6 and later are not vulnerable; first fixed in 12.3	12.3(26)
12.1YF	Vulnerable; first fixed in 12.3	12.3(26)
12.1YG	Not Vulnerable
12.1YH	Vulnerable; first fixed in 12.3	12.3(26)
12.1YI	Vulnerable; first fixed in 12.3	12.3(26)
12.1YJ	Not Vulnerable
Affected 12.2-Based Releases	First Fixed Release	Recommended Release
12.2	Not Vulnerable
12.2B	Vulnerable; first fixed in 12.4	12.4(18a)
12.2BC	Vulnerable; first fixed in 12.3BC	12.3(23)BC1
12.2BW	Vulnerable; first fixed in 12.3	12.3(26)
12.2BY	Vulnerable; first fixed in 12.4	12.4(18a)
12.2BZ	Vulnerable; first fixed in 12.3XI
12.2CX	Vulnerable; first fixed in 12.3BC	12.3(23)BC1
12.2CY	Vulnerable; first fixed in 12.3BC	12.3(23)BC1
12.2CZ	Vulnerable; contact TAC
12.2DA	Not Vulnerable
12.2DD	Vulnerable; first fixed in 12.4	12.4(18a)
12.2DX	Vulnerable; first fixed in 12.4	12.4(18a)
12.2EU	Vulnerable; first fixed in 12.2SG	12.2(25)EWA13 12.2(31)SGA5 12.2(44)SG
12.2EW	Vulnerable; first fixed in 12.2SG	12.2(25)EWA13 12.2(31)SGA5 12.2(44)SG
12.2EWA	12.2(25)EWA10 12.2(25)EWA11	12.2(25)EWA13
12.2EX	12.2(35)EX1 12.2(37)EX	12.2(40)EX1
12.2EY	12.2(37)EY
12.2EZ	Vulnerable; first fixed in 12.2SEE
12.2FX	Vulnerable; first fixed in 12.2SEE
12.2FY	Vulnerable; first fixed in 12.2SEG	12.2(25)SEG4
12.2FZ	Vulnerable; first fixed in 12.2SE	12.2(44)SE1
12.2IXA	Vulnerable; contact TAC
12.2IXB	Vulnerable; contact TAC
12.2IXC	Vulnerable; contact TAC
12.2IXD	Vulnerable; contact TAC
12.2IXE	Not Vulnerable
12.2JA	Vulnerable; first fixed in 12.3JA
12.2JK	Vulnerable; first fixed in 12.4T	12.4(15)T4
12.2MB	Vulnerable; contact TAC
12.2MC	12.2(15)MC2h	12.2(15)MC2k
12.2S	12.2(14)S18 12.2(18)S13 12.2(20)S14 12.2(25)S13	12.2(25)S15
12.2SB	12.2(28)SB7 12.2(31)SB5 12.2(33)SB; Available on 31-MAR-2008	12.2(31)SB11
12.2SBC	Vulnerable; first fixed in 12.2SB; Available on 31-MAR-2008	12.2(31)SB11
12.2SCA	Not Vulnerable
12.2SE	12.2(35)SE4 12.2(37)SE	12.2(44)SE1
12.2SEA	Vulnerable; first fixed in 12.2SEE
12.2SEB	Vulnerable; first fixed in 12.2SEE
12.2SEC	Vulnerable; first fixed in 12.2SEE
12.2SED	Vulnerable; first fixed in 12.2SEE
12.2SEE	12.2(25)SEE4
12.2SEF	12.2(25)SEF3	12.2(44)SE1
12.2SEG	12.2(25)SEG3	12.2(25)SEG4
12.2SG	12.2(25)SG3 12.2(31)SG3 12.2(37)SG	12.2(44)SG
12.2SGA	12.2(31)SGA2 12.2(31)SGA3 12.2(31)SGA6; Available on 07-APR-2008	12.2(31)SGA5
12.2SL	Not Vulnerable
12.2SM	Vulnerable; contact TAC
12.2SO	Vulnerable; migrate to any release in 12.2SVA	12.2(29)SVD
12.2SRA	12.2(33)SRA4	12.2(33)SRA7
12.2SRB	12.2(33)SRB1	12.2(33)SRB3; Available on 14-APR-08
12.2SRC	Not Vulnerable
12.2SU	Vulnerable; first fixed in 12.4	12.4(18a)
12.2SV	12.2(29b)SV	12.2(29b)SV
12.2SVA	Not Vulnerable
12.2SVC	Not Vulnerable
12.2SVD	Not Vulnerable
12.2SW	Vulnerable; contact TAC
12.2SX	Vulnerable; first fixed in 12.2SXF	12.2(18)SXF13
12.2SXA	Vulnerable; first fixed in 12.2SXF	12.2(18)SXF13
12.2SXB	Vulnerable; first fixed in 12.2SXF	12.2(18)SXF13
12.2SXD	Vulnerable; first fixed in 12.2SXF	12.2(18)SXF13
12.2SXE	Vulnerable; first fixed in 12.2SXF	12.2(18)SXF13
12.2SXF	12.2(18)SXF10a 12.2(18)SXF12a 12.2(18)SXF9	12.2(18)SXF13
12.2SXH	Not Vulnerable
12.2SY	Vulnerable; first fixed in 12.2SXF	12.2(18)SXF13
12.2SZ	Vulnerable; first fixed in 12.2S	12.2(25)S15 12.2(31)SB11 12.2(33)SRC
12.2T	Vulnerable; first fixed in 12.3	12.3(26)
12.2TPC	12.2(8)TPC10b
12.2UZ	Vulnerable; first fixed in 12.2SB; Available on 31-MAR-2008	12.2(31)SB11
12.2XA	Vulnerable; first fixed in 12.3	12.3(26)
12.2XB	Vulnerable; first fixed in 12.3	12.3(26)
12.2XC	Vulnerable; first fixed in 12.4	12.4(18a)
12.2XD	Vulnerable; first fixed in 12.3	12.3(26)
12.2XE	Vulnerable; first fixed in 12.3	12.3(26)
12.2XF	Vulnerable; first fixed in 12.3BC	12.3(23)BC1
12.2XG	Vulnerable; first fixed in 12.3	12.3(26)
12.2XH	Vulnerable; first fixed in 12.3	12.3(26)
12.2XI	Vulnerable; first fixed in 12.3	12.3(26)
12.2XJ	Vulnerable; first fixed in 12.3	12.3(26)
12.2XK	Vulnerable; first fixed in 12.3	12.3(26)
12.2XL	Vulnerable; first fixed in 12.3	12.3(26)
12.2XM	Vulnerable; first fixed in 12.3	12.3(26)
12.2XN	12.2(33)XN1	12.3(26)
12.2XO	Not Vulnerable
12.2XQ	Vulnerable; first fixed in 12.3	12.3(26)
12.2XR	Vulnerable; first fixed in 12.3	12.3(26)
12.2XS	Not Vulnerable
12.2XT	Vulnerable; first fixed in 12.3	12.3(26)
12.2XU	Vulnerable; first fixed in 12.3	12.3(26)
12.2XV	Vulnerable; first fixed in 12.3	12.3(26)
12.2XW	Vulnerable; first fixed in 12.3	12.3(26)
12.2YA	12.2(4)YA13; Available on 31-MAR-2008	12.3(26)
12.2YB	Vulnerable; first fixed in 12.3	12.3(26)
12.2YC	Vulnerable; first fixed in 12.3	12.3(26)
12.2YD	Vulnerable; first fixed in 12.4	12.4(18a)
12.2YE	Vulnerable; first fixed in 12.2S	12.2(25)S15 12.2(31)SB11 12.2(33)SRC
12.2YF	Vulnerable; first fixed in 12.3	12.3(26)
12.2YG	Vulnerable; first fixed in 12.3	12.3(26)
12.2YH	Vulnerable; first fixed in 12.3	12.3(26)
12.2YJ	Vulnerable; first fixed in 12.3	12.3(26)
12.2YK	Vulnerable; first fixed in 12.4	12.4(18a)
12.2YL	Vulnerable; first fixed in 12.4	12.4(18a)
12.2YM	Vulnerable; first fixed in 12.4	12.4(18a)
12.2YN	Vulnerable; first fixed in 12.4	12.4(18a)
12.2YO	Vulnerable; first fixed in 12.2SXF	12.2(18)SXF13
12.2YP	Vulnerable; first fixed in 12.3	12.3(26)
12.2YQ	Vulnerable; first fixed in 12.4	12.4(18a)
12.2YR	Vulnerable; first fixed in 12.4	12.4(18a)
12.2YS	Not Vulnerable
12.2YT	Vulnerable; first fixed in 12.3	12.3(26)
12.2YU	Vulnerable; first fixed in 12.4	12.4(18a)
12.2YV	Vulnerable; first fixed in 12.4	12.4(18a)
12.2YW	Vulnerable; first fixed in 12.4	12.4(18a)
12.2YX	Vulnerable; first fixed in 12.4	12.4(18a)
12.2YY	Vulnerable; first fixed in 12.4	12.4(18a)
12.2YZ	Vulnerable; first fixed in 12.2S	12.2(25)S15 12.2(31)SB11 12.2(33)SRC
12.2ZA	Vulnerable; first fixed in 12.2SXF	12.2(18)SXF13
12.2ZB	Vulnerable; first fixed in 12.4	12.4(18a)
12.2ZC	Vulnerable; first fixed in 12.4	12.4(18a)
12.2ZD	Vulnerable; contact TAC
12.2ZE	Vulnerable; first fixed in 12.3	12.3(26)
12.2ZF	Vulnerable; first fixed in 12.4	12.4(18a)
12.2ZG	Vulnerable; first fixed in 12.3YG	12.4(15)T4 12.4(18a)
12.2ZH	12.2(13)ZH9	12.2(13)ZH11
12.2ZJ	Vulnerable; first fixed in 12.4	12.4(18a)
12.2ZL	Vulnerable; first fixed in 12.4	12.4(15)T4 12.4(18a)
12.2ZP	Vulnerable; first fixed in 12.4	12.4(18a)
12.2ZU	Vulnerable; migrate to any release in 12.2SXH	12.2(33)SXH2
12.2ZY	Not Vulnerable
Affected 12.3-Based Releases	First Fixed Release	Recommended Release
12.3	12.3(17c) 12.3(18a) 12.3(19a) 12.3(23)	12.3(26)
12.3B	Vulnerable; first fixed in 12.4	12.4(18a)
12.3BC	12.3(17b)BC8 12.3(21a)BC2 12.3(23)BC	12.3(23)BC1
12.3BW	Vulnerable; first fixed in 12.4	12.4(18a)
12.3EU	Not Vulnerable
12.3JA	12.3(11)JA4 12.3(7)JA5
12.3JEA	12.3(8)JEA2	12.3(8)JEA4
12.3JEB	12.3(8)JEB1	12.3(8)JEB2
12.3JEC	Not Vulnerable
12.3JK	12.3(2)JK3 12.3(8)JK	12.3(8)JK1
12.3JL	12.3(2)JL2	12.3(2)JL4
12.3JX	12.3(7)JX9	12.3(7)JX10
12.3T	Vulnerable; first fixed in 12.4	12.4(18a)
12.3TPC	12.3(4)TPC11b
12.3VA	Vulnerable; contact TAC
12.3XA	12.3(2)XA6	12.3(2)XA7; Available on 31-MAR-08
12.3XB	Vulnerable; first fixed in 12.4	12.4(18a)
12.3XC	12.3(2)XC5	12.4(15)T4 12.4(18a)
12.3XD	Vulnerable; first fixed in 12.4	12.4(18a)
12.3XE	12.3(2)XE6; Available on 31-MAR-2008	12.4(15)T4 12.4(18a)
12.3XF	Vulnerable; first fixed in 12.4	12.4(18a)
12.3XG	Vulnerable; first fixed in 12.3YG	12.4(15)T4 12.4(18a)
12.3XH	Vulnerable; first fixed in 12.4	12.4(18a)
12.3XI	12.3(7)XI10
12.3XJ	Vulnerable; first fixed in 12.3YX	12.3(14)YX11 12.4(15)T4
12.3XK	Vulnerable; first fixed in 12.4	12.4(18a)
12.3XQ	Vulnerable; first fixed in 12.4	12.4(18a)
12.3XR	12.3(7)XR7	12.3(7)XR8; Available on 31-MAR-08
12.3XS	Vulnerable; first fixed in 12.4	12.4(18a)
12.3XU	Vulnerable; first fixed in 12.4T	12.4(15)T4
12.3XW	Vulnerable; first fixed in 12.3YX	12.3(14)YX11 12.4(15)T4
12.3XY	Vulnerable; first fixed in 12.4	12.4(18a)
12.3YA	Vulnerable; first fixed in 12.4	12.4(15)T4 12.4(18a)
12.3YD	Vulnerable; first fixed in 12.4T	12.4(15)T4
12.3YF	Vulnerable; first fixed in 12.3YX	12.3(14)YX11 12.4(15)T4
12.3YG	12.3(8)YG6	12.4(15)T4
12.3YH	Vulnerable; first fixed in 12.4T	12.4(15)T4
12.3YI	Vulnerable; first fixed in 12.4T	12.4(15)T4
12.3YJ	Vulnerable; first fixed in 12.4T	12.4(15)T4
12.3YK	12.3(11)YK3	12.4(15)T4
12.3YM	12.3(14)YM10	12.3(14)YM12
12.3YQ	Vulnerable; first fixed in 12.4T	12.4(15)T4
12.3YS	12.3(11)YS3; Available on 31-MAR-2008	12.4(15)T4
12.3YT	Vulnerable; first fixed in 12.4T	12.4(15)T4
12.3YU	Vulnerable; first fixed in 12.4XB
12.3YX	12.3(14)YX8	12.3(14)YX11
12.3YZ	12.3(11)YZ2
Affected 12.4-Based Releases	First Fixed Release	Recommended Release
12.4	12.4(10c) 12.4(12) 12.4(3h) 12.4(5c) 12.4(7e) 12.4(8d)	12.4(18a)
12.4JA	Not Vulnerable
12.4JK	Not Vulnerable
12.4JMA	Not Vulnerable
12.4JMB	Not Vulnerable
12.4JMC	Not Vulnerable
12.4JX	Not Vulnerable
12.4MD	Not Vulnerable
12.4MR	12.4(12)MR	12.4(16)MR2
12.4SW	12.4(11)SW3	12.4(15)SW
12.4T	12.4(11)T2 12.4(15)T 12.4(2)T6 12.4(4)T8 12.4(6)T8 12.4(9)T3	12.4(15)T4
12.4XA	Vulnerable; first fixed in 12.4T	12.4(15)T4
12.4XB	12.4(2)XB6
12.4XC	12.4(4)XC7
12.4XD	12.4(4)XD7	12.4(4)XD10
12.4XE	12.4(6)XE2	12.4(15)T4
12.4XF	Not Vulnerable
12.4XG	12.4(9)XG2	12.4(9)XG2
12.4XJ	12.4(11)XJ4	12.4(15)T4
12.4XK	Not Vulnerable
12.4XL	Not Vulnerable
12.4XM	Not Vulnerable
12.4XN	Not Vulnerable
12.4XT	12.4(6)XT1	12.4(6)XT2
12.4XV	Not Vulnerable
12.4XW	Not Vulnerable
12.4XY	Not Vulnerable

Exploitation and Public Announcements

The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.

This vulnerability was encountered in customer networks.

Cisco Security Vulnerability Policy

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.

Subscribe to Cisco Security Notifications

Action Links for This Advisory

User Datagram Protocol Delivery Issue For IPv4/IPv6 Dual-stack Routers

Related to This Advisory

Cisco IOS IPv6 UDP Packet Handling Denial of Service Vulnerability

URL

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080326-IPv4IPv6

Revision History

Revision 1.5	2008-June-27	Updated Summary to remove link and verbiage.
Revision 1.4	2008-April-25	Updated CVSS link for CSCse56501.
Revision 1.3	2008-April-14	Link-local address space is added to the iACL example in the Workarounds section
Revision 1.2	2008-April-01	Added workaround using rACL for Cisco routers 12000, 7500 and 10720 series.
Revision 1.1	2008-Mar-29	Updated Software Table for 12.0S, 12.0SY, 12.0SX and 12.0SZ due to new information on advisory ID cisco-sa-20080326-IPv4IPv6, the March 26th advisory on IPv4IPv6 Dual Stack Routers.
Revision 1.0	2008-Mar-26	Initial public release

Show Less

Legal Disclaimer

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 is an uncontrolled copy, and may lack important information or contain factual errors. The information in this document is intended for end-users of Cisco products.

Feedback

Leave additional feedback

Cisco Security Vulnerability Policy

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.

Cisco Security Advisory

Cisco IOS User Datagram Protocol Delivery Issue For IPv4/IPv6 Dual-stack Routers

Summary

Affected Products

Vulnerable Products

How To Verify If IPv6 Is Enabled

How To Verify If IPv4 UDP-based Services Are Enabled

Products Confirmed Not Vulnerable

Details

Identification Of Vulnerability Exploitation

Workarounds

Interface Access Control List

Receive Access Control List

Additional Mitigation Techniques

Fixed Software

Exploitation and Public Announcements

Cisco Security Vulnerability Policy

Subscribe to Cisco Security Notifications

Action Links for This Advisory

Related to This Advisory

URL

Revision History

Legal Disclaimer

Feedback

Cisco Security Vulnerability Policy

Subscribe to Cisco Security Notifications

Action Links for This Advisory

Related to This Advisory