Advisory ID: cisco-sa-20080924-vpnRevision 1.2
For Public Release 2008 September 24 16:00 UTC (GMT)
Devices running Cisco IOS versions 12.0S, 12.2, 12.3 or 12.4 and
configured for Multiprotocol Label Switching (MPLS) Virtual Private Networks
(VPNs) or VPN Routing and Forwarding Lite (VRF Lite) and using Border Gateway
Protocol (BGP) between Customer Edge (CE) and Provider Edge (PE) devices may
permit information to propagate between VPNs.
Workarounds are available to help mitigate this
vulnerability.
This issue is triggered by a logic error when processing
extended communities on the PE device.
This issue cannot be deterministically exploited by an
attacker.
Cisco has released free software updates that address these
vulnerabilities. Workarounds that mitigate these vulnerabilities are
available.
This advisory is posted at
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080924-vpn.
The September 24, 2008 IOS Advisory bundled publication includes twelve
Security Advisories. Eleven of the advisories address vulnerabilities in
Cisco's IOS software, and one advisory addresses vulnerabilities in Cisco
Unified Communications Manager. Each Advisory lists the releases that correct
the vulnerability described in the Advisory.
Individual publication links are listed below:
Products running Cisco IOS versions 12.0S, 12.2, 12.3 or 12.4 and
configured for MPLS VPNs or VRF Lite are potentially affected.
Cisco IOS releases based on 12.1 are not affected.
Cisco IOS devices are vulnerable if they are configured for MPLS VPN or
VRF Lite and have a BGP session between the CE and PE devices, and process
extended communities. If a device is configured for MPLS VPN or VRF Lite the
command address-family ipv4 vrf
<vrf-name> or
address-family ipv6 vrf
<vrf-name> will be present in the
device configuration.
The following shows a command executed on a device
configured for MPLS VPN:
router#show running-config | include address-family [ipv4|ipv6]
address-family ipv4 vrf <vrf-name>
The following shows a PE device configured for an IPv4 BGP session
between the PE and the CE:
router bgp <Local AS>
address-family ipv4 vrf one
neighbor <neighbor IP> remote-as < Remote AS>
neighbor <neighbor IP> activate
To determine the software running on a Cisco 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 IOS release name. Other
Cisco devices will not have the "show version" command or will give different
output.
The following example identifies a Cisco product that is
running Cisco IOS release 12.4(11)T2:
Router#show version
Cisco IOS Software, 7200 Software (C7200-ADVSECURITYK9-M), Version 12.4(11)T2, RELEASE SOFTWARE (fc4)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2007 by Cisco Systems, Inc.
Compiled Tue 01-May-07 04:19 by prod_rel_team
<output truncated>
Additional information on the Cisco IOS release naming conventions can
be found on the document entitled "White Paper: Cisco IOS Reference Guide",
which is available at http://www.cisco.com/web/about/security/intelligence/ios-ref.html
Cisco products not configured for MPLS VPNs or VRF Lite are unaffected
by this vulnerability.
Cisco products that do not run IOS are unaffected by this
vulnerability.
Cisco IOS-XR is not affected.
No other Cisco products are currently known to be affected
by this vulnerability.
MPLS VPNs allow for the creation of 'virtual networks' that customers
can use to segregate traffic into multiple, isolated VPNs. Traffic within each
MPLS VPN is kept separate from the others, thereby maintaining a virtual
private network.
More information on MPLS and MPLS VPNs is available at the
following link:
http://www.cisco.com/en/US/products/ps6557/products_ios_technology_home.html
A bug exists when processing extended communities with MPLS
VPNs. If extended communities are used, MPLS VPN may incorrectly use a
corrupted route target (RT) to forward traffic. If this occurs, traffic can
leak from one MPLS VPN to another.
This vulnerability exists whenever an affected PE device
has a BGP session running in the MPLS VPN Virtual Routing and Forwarding (VRF).
The following two examples of this scenario are the most common:
1) MPLS VPN configuration with BGP running inside the VRF
between the PE and CE devices.
2) MPLS Inter-AS option A with BGP running between the
Autonomous System Border Routers (ASBR).
The mitigation in the Workarounds section filters extended
communities on a PE device, preventing them from being received by devices
configured for MPLS VPN.
This vulnerability was introduced with Cisco bug ID
CSCee83237. Cisco IOS images that do not include CSCee83237 are not vulnerable
to this issue.
It is important to note that this condition cannot be
triggered by an attacker and that the condition does not provide ways to
determine the flow of traffic between VPNs.
This vulnerability is documented in the Cisco Bug ID
CSCec12299
(
registered customers only)
and has been assigned
Common Vulnerabilities and Exposures (CVE) ID CVE-2008-3803.
Cisco has provided scores for the vulnerabilities in this advisory
based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in
this Security Advisory is done in accordance with CVSS version 2.0.
CVSS is a standards-based scoring method that conveys
vulnerability severity and helps determine urgency and priority of response.
Cisco has provided a base and temporal score. Customers can
then compute environmental scores to assist in determining the impact of the
vulnerability in individual networks.
Cisco has provided an FAQ to answer additional questions
regarding CVSS at
http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html .
Cisco has also provided a CVSS calculator to help compute
the environmental impact for individual networks at
http://intellishield.cisco.com/security/alertmanager/cvss .
|
CSCec12299 - Corruption of ext communities when receiving over
ipv4 EBGP session
Calculate the environmental score of
CSCec12299
|
|
CVSS Base Score - 5.1
|
|
Access Vector
|
Access Complexity
|
Authentication
|
Confidentiality Impact
|
Integrity Impact
|
Availability Impact
|
|
Network
|
High
|
None
|
Partial
|
Partial
|
Partial
|
|
CVSS Temporal Score - 4.2
|
|
Exploitability
|
Remediation Level
|
Report Confidence
|
|
Functional
|
Official-Fix
|
Confirmed
|
This vulnerability may cause traffic to be improperly routed between
MPLS VPNs, which may lead to a breach of confidentiality.
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
|
12.0(30)S5
12.0(31)S3
12.0(32)S
|
12.0(32)S11
12.0(33)S1
|
|
12.0SC
|
Not Vulnerable
|
|
|
12.0SL
|
Not Vulnerable
|
|
|
12.0SP
|
Not Vulnerable
|
|
|
12.0ST
|
Not Vulnerable
|
|
|
12.0SX
|
Vulnerable; first fixed in 12.0S
|
12.0(32)S11
12.0(33)S1
|
|
12.0SY
|
Not Vulnerable
|
|
|
12.0SZ
|
12.0(30)SZ4
|
12.0(32)S11
12.0(33)S1
|
|
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
|
|
|
12.0XT
|
Not Vulnerable
|
|
|
12.0XV
|
Not Vulnerable
|
|
|
Affected 12.1-Based Releases
|
First Fixed Release
|
Recommended Release
|
|
There are no affected 12.1 based releases
|
|
Affected 12.2-Based Releases
|
First Fixed Release
|
Recommended Release
|
|
12.2
|
Not Vulnerable
|
|
|
12.2B
|
Not Vulnerable
|
|
|
12.2BC
|
Not Vulnerable
|
|
|
12.2BW
|
Not Vulnerable
|
|
|
12.2BX
|
Not Vulnerable
|
|
|
12.2BY
|
Not Vulnerable
|
|
|
12.2BZ
|
Not Vulnerable
|
|
|
12.2CX
|
Not Vulnerable
|
|
|
12.2CY
|
Not Vulnerable
|
|
|
12.2CZ
|
Not Vulnerable
|
|
|
12.2DA
|
Not Vulnerable
|
|
|
12.2DD
|
Not Vulnerable
|
|
|
12.2DX
|
Not Vulnerable
|
|
|
12.2EW
|
Not Vulnerable
|
|
|
12.2EWA
|
Not Vulnerable
|
|
|
12.2EX
|
Not Vulnerable
|
|
|
12.2EY
|
Not Vulnerable
|
|
|
12.2EZ
|
Not Vulnerable
|
|
|
12.2FX
|
Not Vulnerable
|
|
|
12.2FY
|
Not Vulnerable
|
|
|
12.2FZ
|
Not Vulnerable
|
|
|
12.2IRB
|
Not Vulnerable
|
|
|
12.2IXA
|
Vulnerable; migrate to any release in 12.2IXD
|
12.2(18)IXG
|
|
12.2IXB
|
Vulnerable; migrate to any release in 12.2IXD
|
12.2(18)IXG
|
|
12.2IXC
|
Vulnerable; migrate to any release in 12.2IXD
|
12.2(18)IXG
|
|
12.2IXD
|
Not Vulnerable
|
|
|
12.2IXE
|
Not Vulnerable
|
|
|
12.2IXF
|
Not Vulnerable
|
|
|
12.2IXG
|
Not Vulnerable
|
|
|
12.2JA
|
Not Vulnerable
|
|
|
12.2JK
|
Not Vulnerable
|
|
|
12.2MB
|
Not Vulnerable
|
|
|
12.2MC
|
Not Vulnerable
|
|
|
12.2S
|
12.2(30)S and later are vulnerable. 12.2(25)S and before are not
vulnerable
|
12.2(33)SB2; Available on 26-SEP-08
|
|
12.2SB
|
12.2(28)SB5
12.2(31)SB2
12.2(31)SB3x
|
12.2(33)SB2; Available on 26-SEP-08
|
|
12.2SBC
|
Vulnerable; first fixed in 12.2SB
|
12.2(33)SB2; Available on 26-SEP-08
|
|
12.2SCA
|
Not Vulnerable
|
|
|
12.2SE
|
Not Vulnerable
|
|
|
12.2SEA
|
Not Vulnerable
|
|
|
12.2SEB
|
Not Vulnerable
|
|
|
12.2SEC
|
Not Vulnerable
|
|
|
12.2SED
|
Not Vulnerable
|
|
|
12.2SEE
|
Not Vulnerable
|
|
|
12.2SEF
|
Not Vulnerable
|
|
|
12.2SEG
|
Not Vulnerable
|
|
|
12.2SG
|
12.2(37)SG
|
12.2(46)SG1
|
|
12.2SGA
|
12.2(31)SGA8
|
12.2(31)SGA8
|
|
12.2SL
|
Not Vulnerable
|
|
|
12.2SM
|
12.2(29)SM2
|
12.2(29)SM4
|
|
12.2SO
|
Not Vulnerable
|
|
|
12.2SRA
|
Not Vulnerable
|
|
|
12.2SRB
|
Not Vulnerable
|
|
|
12.2SRC
|
Not Vulnerable
|
|
|
12.2SU
|
Not Vulnerable
|
|
|
12.2SV
|
12.2(29b)SV1
|
|
|
12.2SVA
|
Not Vulnerable
|
|
|
12.2SVC
|
Not Vulnerable
|
|
|
12.2SVD
|
Not Vulnerable
|
|
|
12.2SW
|
Not Vulnerable
|
|
|
12.2SX
|
Not Vulnerable
|
|
|
12.2SXA
|
Not Vulnerable
|
|
|
12.2SXB
|
Not Vulnerable
|
|
|
12.2SXD
|
Not Vulnerable
|
|
|
12.2SXE
|
Vulnerable; first fixed in 12.2SXF
|
12.2(18)SXF15
|
|
12.2SXF
|
12.2(18)SXF3
|
12.2(18)SXF15
|
|
12.2SXH
|
Not Vulnerable
|
|
|
12.2SY
|
Not Vulnerable
|
|
|
12.2SZ
|
Not Vulnerable
|
|
|
12.2T
|
Not Vulnerable
|
|
|
12.2TPC
|
Not Vulnerable
|
|
|
12.2XA
|
Not Vulnerable
|
|
|
12.2XB
|
Not Vulnerable
|
|
|
12.2XC
|
Not Vulnerable
|
|
|
12.2XD
|
Not Vulnerable
|
|
|
12.2XE
|
Not Vulnerable
|
|
|
12.2XF
|
Not Vulnerable
|
|
|
12.2XG
|
Not Vulnerable
|
|
|
12.2XH
|
Not Vulnerable
|
|
|
12.2XI
|
Not Vulnerable
|
|
|
12.2XJ
|
Not Vulnerable
|
|
|
12.2XK
|
Not Vulnerable
|
|
|
12.2XL
|
Not Vulnerable
|
|
|
12.2XM
|
Not Vulnerable
|
|
|
12.2XN
|
Not Vulnerable
|
|
|
12.2XNA
|
Not Vulnerable
|
|
|
12.2XNB
|
Not Vulnerable
|
|
|
12.2XO
|
Not Vulnerable
|
|
|
12.2XQ
|
Not Vulnerable
|
|
|
12.2XR
|
Not Vulnerable
|
|
|
12.2XS
|
Not Vulnerable
|
|
|
12.2XT
|
Not Vulnerable
|
|
|
12.2XU
|
Not Vulnerable
|
|
|
12.2XV
|
Not Vulnerable
|
|
|
12.2XW
|
Not Vulnerable
|
|
|
12.2YA
|
Not Vulnerable
|
|
|
12.2YB
|
Not Vulnerable
|
|
|
12.2YC
|
Not Vulnerable
|
|
|
12.2YD
|
Not Vulnerable
|
|
|
12.2YE
|
Not Vulnerable
|
|
|
12.2YF
|
Not Vulnerable
|
|
|
12.2YG
|
Not Vulnerable
|
|
|
12.2YH
|
Not Vulnerable
|
|
|
12.2YJ
|
Not Vulnerable
|
|
|
12.2YK
|
Not Vulnerable
|
|
|
12.2YL
|
Not Vulnerable
|
|
|
12.2YM
|
Not Vulnerable
|
|
|
12.2YN
|
Not Vulnerable
|
|
|
12.2YO
|
Not Vulnerable
|
|
|
12.2YP
|
Not Vulnerable
|
|
|
12.2YQ
|
Not Vulnerable
|
|
|
12.2YR
|
Not Vulnerable
|
|
|
12.2YS
|
Not Vulnerable
|
|
|
12.2YT
|
Not Vulnerable
|
|
|
12.2YU
|
Not Vulnerable
|
|
|
12.2YV
|
Not Vulnerable
|
|
|
12.2YW
|
Not Vulnerable
|
|
|
12.2YX
|
Not Vulnerable
|
|
|
12.2YY
|
Not Vulnerable
|
|
|
12.2YZ
|
Not Vulnerable
|
|
|
12.2ZA
|
Not Vulnerable
|
|
|
12.2ZB
|
Not Vulnerable
|
|
|
12.2ZC
|
Not Vulnerable
|
|
|
12.2ZD
|
Not Vulnerable
|
|
|
12.2ZE
|
Not Vulnerable
|
|
|
12.2ZF
|
Not Vulnerable
|
|
|
12.2ZG
|
Not Vulnerable
|
|
|
12.2ZH
|
Not Vulnerable
|
|
|
12.2ZJ
|
Not Vulnerable
|
|
|
12.2ZL
|
Not Vulnerable
|
|
|
12.2ZP
|
Not Vulnerable
|
|
|
12.2ZU
|
Not Vulnerable
|
|
|
12.2ZX
|
Vulnerable; first fixed in 12.2SB
|
12.2(33)SB2; Available on 26-SEP-08
|
|
12.2ZY
|
Not Vulnerable
|
|
|
12.2ZYA
|
Not Vulnerable
|
|
|
Affected 12.3-Based Releases
|
First Fixed Release
|
Recommended Release
|
|
12.3
|
Not Vulnerable
|
|
|
12.3B
|
Not Vulnerable
|
|
|
12.3BC
|
Not Vulnerable
|
|
|
12.3BW
|
Not Vulnerable
|
|
|
12.3EU
|
Not Vulnerable
|
|
|
12.3JA
|
Not Vulnerable
|
|
|
12.3JEA
|
Not Vulnerable
|
|
|
12.3JEB
|
Not Vulnerable
|
|
|
12.3JEC
|
Not Vulnerable
|
|
|
12.3JK
|
Not Vulnerable
|
|
|
12.3JL
|
Not Vulnerable
|
|
|
12.3JX
|
Not Vulnerable
|
|
|
12.3T
|
Vulnerable; first fixed in 12.4
|
12.4(15)T7
12.4(18c)
|
|
12.3TPC
|
Not Vulnerable
|
|
|
12.3VA
|
Not Vulnerable
|
|
|
12.3XA
|
Not Vulnerable
|
|
|
12.3XB
|
Not Vulnerable
|
|
|
12.3XC
|
Not Vulnerable
|
|
|
12.3XD
|
Not Vulnerable
|
|
|
12.3XE
|
Not Vulnerable
|
|
|
12.3XF
|
Not Vulnerable
|
|
|
12.3XG
|
Not Vulnerable
|
|
|
12.3XI
|
Not Vulnerable
|
|
|
12.3XJ
|
Not Vulnerable
|
|
|
12.3XK
|
Not Vulnerable
|
|
|
12.3XL
|
Vulnerable; first fixed in 12.4
|
12.4(15)T7
12.4(18c)
|
|
12.3XQ
|
Not Vulnerable
|
|
|
12.3XR
|
Not Vulnerable
|
|
|
12.3XS
|
Not Vulnerable
|
|
|
12.3XU
|
Not Vulnerable
|
|
|
12.3XW
|
Not Vulnerable
|
|
|
12.3XX
|
Not Vulnerable
|
|
|
12.3XY
|
Not Vulnerable
|
|
|
12.3XZ
|
Not Vulnerable
|
|
|
12.3YA
|
Not Vulnerable
|
|
|
12.3YD
|
Not Vulnerable
|
|
|
12.3YF
|
Vulnerable; first fixed in 12.3YX
|
12.3(14)YX13
12.4(15)T7
|
|
12.3YG
|
Not Vulnerable
|
|
|
12.3YH
|
Not Vulnerable
|
|
|
12.3YI
|
Not Vulnerable
|
|
|
12.3YJ
|
Vulnerable; first fixed in 12.4T
|
12.4(15)T7
|
|
12.3YK
|
12.3(11)YK3
|
12.4(15)T7
|
|
12.3YM
|
12.3(14)YM10
|
12.3(14)YM13; Available on 30-SEP-08
|
|
12.3YQ
|
Vulnerable; first fixed in 12.4T
|
12.4(15)T7
|
|
12.3YS
|
12.3(11)YS2
|
12.4(15)T7
|
|
12.3YT
|
Vulnerable; first fixed in 12.4T
|
12.4(15)T7
|
|
12.3YU
|
Vulnerable; first fixed in 12.4XB
|
12.4(2)XB10
12.4(9)XG3
12.4(15)T7
|
|
12.3YX
|
12.3(14)YX7
|
12.3(14)YX13
|
|
12.3YZ
|
12.3(11)YZ2
|
|
|
12.3ZA
|
Not Vulnerable
|
|
|
Affected 12.4-Based Releases
|
First Fixed Release
|
Recommended Release
|
|
12.4
|
12.4(10c)
12.4(12a)
12.4(13)
12.4(3h)
12.4(5c)
12.4(7e)
12.4(8d)
|
12.4(18c)
|
|
12.4JA
|
Not Vulnerable
|
|
|
12.4JK
|
Not Vulnerable
|
|
|
12.4JL
|
Not Vulnerable
|
|
|
12.4JMA
|
Not Vulnerable
|
|
|
12.4JMB
|
Not Vulnerable
|
|
|
12.4JMC
|
Not Vulnerable
|
|
|
12.4JX
|
Not Vulnerable
|
|
|
12.4MD
|
Not Vulnerable
|
|
|
12.4MR
|
Not Vulnerable
|
|
|
12.4SW
|
12.4(11)SW1
|
12.4(15)SW2; Available on 28-SEP-08
|
|
12.4T
|
12.4(11)T2
12.4(15)T
12.4(2)T6
12.4(4)T8
12.4(6)T7
12.4(9)T3
|
12.4(15)T7
|
|
12.4XA
|
Vulnerable; first fixed in 12.4T
|
12.4(15)T7
|
|
12.4XB
|
12.4(2)XB6
|
12.4(2)XB10
|
|
12.4XC
|
12.4(4)XC7
|
12.4(15)T7
|
|
12.4XD
|
12.4(4)XD7
|
12.4(4)XD11; Available on 26-SEP-08
|
|
12.4XE
|
12.4(6)XE3
|
12.4(15)T7
|
|
12.4XF
|
Not Vulnerable
|
|
|
12.4XG
|
12.4(9)XG2
|
12.4(9)XG3
|
|
12.4XJ
|
12.4(11)XJ2
|
12.4(15)T7
|
|
12.4XK
|
Vulnerable; first fixed in 12.4T
|
12.4(15)T7
|
|
12.4XL
|
Not Vulnerable
|
|
|
12.4XM
|
Not Vulnerable
|
|
|
12.4XN
|
Not Vulnerable
|
|
|
12.4XP
|
Vulnerable; contact TAC
|
|
|
12.4XQ
|
Not Vulnerable
|
|
|
12.4XR
|
Not Vulnerable
|
|
|
12.4XT
|
12.4(6)XT1
|
12.4(15)T7
|
|
12.4XV
|
Not Vulnerable
|
|
|
12.4XW
|
Not Vulnerable
|
|
|
12.4XY
|
Not Vulnerable
|
|
|
12.4XZ
|
Not Vulnerable
|
|
|
12.4YA
|
Not Vulnerable
|
|
Customers running versions of Cisco IOS that support filtering of
extended communities can prevent the corruption of the route target (RT) by
applying a BGP route-map that removes RT entries on inbound BGP
sessions.
The following configuration example applied in the ipv4
address family of a PE device removes extended communities from the CE
router:
router bgp <Local AS>
address-family ipv4 vrf one
neighbor <neighbor IP> remote-as <Remote AS>
neighbor <neighbor IP> activate
neighbor <neighbor IP> route-map FILTER in
exit-address-family
!
ip extcommunity-list 100 permit _RT.*_
!
!
route-map FILTER permit 10
set extcomm-list 100 delete
!
The following configuration example applied in the ipv6 address family
of a PE device removes extended communities from the CE router:
router bgp <Local AS>
address-family ipv6 vrf one
neighbor <neighbor IP> remote-as <Remote AS>
neighbor <neighbor IP> activate
neighbor <neighbor IP> route-map FILTER in
exit-address-family
!
ip extcommunity-list 100 permit _RT.*_
!
!
route-map FILTER permit 10
set extcomm-list 100 delete
!
Note: The capability of filtering extended communities is only available
in certain 12.0S and 12.2S based Cisco IOS releases.
BGP session between the PE and the CE needs to cleared to
make this configuration change effective.
Cisco has released free software updates that address these
vulnerabilities. Prior to deploying software, customers should consult their
maintenance provider or check the software for feature set compatibility and
known issues specific to their environment.
Customers may only install and expect support for the
feature sets they have purchased. By installing, downloading, accessing or
otherwise using such software upgrades, customers agree to be bound by the
terms of Cisco's software license terms found at
http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html,
or as otherwise set forth at Cisco.com Downloads at
http://www.cisco.com/public/sw-center/sw-usingswc.shtml.
Do not contact psirt@cisco.com or security-alert@cisco.com
for software upgrades.
Customers with contracts should obtain upgraded software through their
regular update channels. For most customers, this means that upgrades should be
obtained through the Software Center on Cisco's worldwide website at
http://www.cisco.com.
Customers whose Cisco products are provided or maintained through prior
or existing agreements with third-party support organizations, such as Cisco
Partners, authorized resellers, or service providers should contact that
support organization for guidance and assistance with the appropriate course of
action in regards to this advisory.
The effectiveness of any workaround or fix is dependent on
specific customer situations, such as product mix, network topology, traffic
behavior, and organizational mission. Due to the variety of affected products
and releases, customers should consult with their service provider or support
organization to ensure any applied workaround or fix is the most appropriate
for use in the intended network before it is deployed.
Customers who purchase direct from Cisco but do not hold a Cisco
service contract, and customers who purchase through third-party vendors but
are unsuccessful in obtaining fixed software through their point of sale should
acquire upgrades by contacting the Cisco Technical Assistance Center (TAC). TAC
contacts are as follows.
-
+1 800 553 2447 (toll free from within North America)
-
+1 408 526 7209 (toll call from anywhere in the world)
-
e-mail: tac@cisco.com
Customers should have their product serial number available and be
prepared to give the URL of this notice as evidence of entitlement to a free
upgrade. Free upgrades for non-contract customers must be requested through the
TAC.
Refer to
http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml
for additional TAC contact information, including localized telephone numbers,
and instructions and e-mail addresses for use in various languages.
The Cisco PSIRT is not aware of any public announcements or malicious
use of the vulnerability described in this advisory.
This vulnerability was reported to Cisco by a
customer.
This vulnerability cannot be deterministically triggered by
an attacker.
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 in the following section is an uncontrolled copy, and may lack important information or contain factual errors.
This advisory is posted on Cisco's worldwide website at :
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080924-vpn
In addition to worldwide web posting, a text version of
this notice is clear-signed with the Cisco PSIRT PGP key and is posted to the
following e-mail and Usenet news recipients.
-
cust-security-announce@cisco.com
-
first-bulletins@lists.first.org
-
bugtraq@securityfocus.com
-
vulnwatch@vulnwatch.org
-
cisco@spot.colorado.edu
-
cisco-nsp@puck.nether.net
-
full-disclosure@lists.grok.org.uk
-
comp.dcom.sys.cisco@newsgate.cisco.com
Future updates of this advisory, if any, will be placed on Cisco's
worldwide website, but may or may not be actively announced on mailing lists or
newsgroups. Users concerned about this problem are encouraged to check the
above URL for any updates.
|
Revision 1.2
|
2009-April-16
|
Removed references to the combined software table, as it is now
outdated.
|
|
Revision 1.1
|
2008-Nov-19
|
Updated configuration examples in Workarounds section.
|
|
Revision 1.0
|
2008-Sep-24
|
Initial public release.
|
|
