Guest

Product Support

Cisco IOS Misformed BGP Packet Causes Reload

Advisory ID: cisco-sa-20050126-bgp

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20050126-bgp

Revision 1.5

For Public Release 2005 January 26 16:00  UTC (GMT)


Summary

A Cisco device running IOS Border Gateway Protocol (BGP) is vulnerable to a Denial of Service (DoS) attack from a malformed BGP packet. Only devices with either the command bgp log-neighbor-changes configured or the command snmp-server enable traps bgp are vulnerable. The BGP protocol is not enabled by default, and must be configured in order to accept traffic from an explicitly defined peer. Unless the malicious traffic appears to be sourced from a configured, trusted peer, it would be difficult to inject a malformed packet.

Cisco has made free software available to address this problem.

This issue is tracked by CERT/CC VU#689326.

This advisory will be posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20050126-bgp.

Affected Products

This section provides details on affected products.

Vulnerable Products

This vulnerability is present in any unfixed version of Cisco IOS, from the beginning of support for the BGP protocol, including versions 9.x, 10.x, 11.x and 12.x. This issue affects all Cisco devices configured for BGP routing and configured with either the bgp log-neighbor-changes command or snmp-server enable traps bgp. The bgp log-neighbor-changes command is on by default in 12.0(22)S, 12.0(11)ST, 12.1(10)E, 12.1(10) and later software.

Cisco IOS XR is also affected.

A router that is running the BGP process will have the following line in the configuration:

router bgp <AS number>

In order for the device to be impacted, one or both of the following configuration commands must be enabled:

bgp log-neighbor-changes  

or

snmp-server enable traps bgp

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 running IOS release 12.0(3) with an installed image name of C2500-IS-L:

Cisco Internetwork Operating System Software IOS (TM)
    
2500 Software (C2500-IS-L), Version 12.0(3), RELEASE SOFTWARE

The release train label is "12.0."

The next example shows a product running IOS release 12.0(2a)T1 with an image name of C2600-JS-MZ:

Cisco Internetwork Operating System Software IOS (tm)
C2600 Software (C2600-JS-MZ), Version 12.0(2a)T1, RELEASE SOFTWARE (fc1)

Additional information about Cisco IOS release naming can be found at: http://www.cisco.com/warp/public/620/1.html.

Products Confirmed Not Vulnerable

Products confirmed not to be vulnerable include devices that do not run Cisco IOS, such as the Cisco Guard, products that cannot participate in BGP or products that cannot be configured for BGP. No other Cisco products are currently known to be affected by this vulnerability.

Details

The Border Gateway Protocol (BGP) is a routing protocol defined by RFC 1771, and designed to manage IP routing in large networks. An affected Cisco device running a vulnerable version of Cisco IOS software with the BGP protocol enabled will reload if a malformed BGP packet is already queued on the interface when a BGP neighbor change is logged. The device is not vulnerable unless either bgp log-neighbor-changes is configured or snmp-server traps enable bgp is configured.

Malformed packets can not only come from malicious sources. A valid peering device such as another BGP speaking router that produces the specific malformed packet in error can trigger this behavior.

In all cases, however, the packets must be sourced from an IP address that is explicitly configured.

BGP runs over the Transport Control Protocol (TCP), a reliable transport protocol which requires a valid three way handshake before any further messages will be accepted. The Cisco IOS implementation of BGP requires the explicit definition of a neighbor before a connection can be established, and traffic must appear to come from that neighbor. These implementation details make it very difficult to maliciously send a BGP packet to a Cisco IOS device from an unauthorized source.

This bug may also be triggered by other means which are not considered remotely exploitable. The use of the commands show ip bgp neighbors or debug ip bgp can cause a router to reload if the device has previously received a malformed packet.

Additionally, using an SNMP management station to poll the SNMP Object Identifier (OID) bgpPeerEntry.bgpPeerLastError (1.3.6.1.2.1.15.3.1.14) may cause the device to reset. This may only happen after the device has received the malformed packet and the BGP session is reset.

A Cisco IOS device receiving an invalid BGP packet will reset and may take several minutes to become fully functional. This vulnerability may be exploited repeatedly resulting in an extended DoS attack. This issue is documented in bug ID CSCee67450 ( registered customers only) .

A Cisco IOS XR device will restart the BGP process. All the sessions will be dropped and BGP process will have to re-establish sessions with its peers. No other routing protocols will be affected.

If graceful restart is enabled, forwarding should not be impacted.

In IOS XR, the BGP process is not mandatory by default. Unless the user has explicitly configured the BGP process to be mandatory, the IOS XR device will not reload.

Vulnerability Scoring Details

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 .


Impact

Successful exploitation of this vulnerability on an IOS device results in a reload of the device. Repeated exploitation could result in a sustained DoS attack.

Successful exploitation of this vulnerability on an IOS XR device results in a restart of the BGP process. Repeated exploitation could result in a sustained DoS attack against BGP functionality. Other services on the device are not affected.

Software Versions and Fixes

When considering software upgrades, please also consult http://www.cisco.com/en/US/products/products_security_advisories_listing.html 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") for assistance.

Cisco customers running IOS XR software should contact Cisco's TAC for repaired software.

Major Release

Availability of Repaired Releases

Affected 12.0-Based Release

Rebuild

Maintenance Release

12.0

12.0(28b)

 

12.0DA

Vulnerable; contact TAC

 

12.0DB

Migrate to 12.3(4)T11 or later

 

12.0DC

Migrate to 12.3(4)T11 or later

 

12.0S

12.0(25)S5

 

12.0(26)S2d

 

12.0(26)S5

 

12.0(27)S2d

12.0(27)S4

 

12.0(28)S1

 
 

12.0(29)S

12.0SC

Vulnerable; contact TAC

 

12.0SP

Migrate to 12.0S or later

 

12.0ST

Migrate to 12.0(26)S5 or later

 

12.OSV

12.0(27)SV4

 

12.0SX

Vulnerable; contact TAC

 

12.0SY

Migrate to 12.0(26)S5 or later

 

12.0SZ

Migrate to 12.0(26)S5 or later

 

12.0W5

 

12.0(28)W5

(31)

12.0WC

Vulnerable; contact TAC

 

12.0WT

Vulnerable; contact TAC

 

12.0WX

Vulnerable; contact TAC

 

12.0XA

Migrate to 12.1 latest

 

12.0XB

Migrate to 12.0(1)T or later

 

12.0XC

Migrate to 12.1 latest

 

12.0XD

Migrate to 12.1 latest

 

12.0XE

Migrate to 12.1E latest

 

12.0XF

Vulnerable; contact TAC

 

12.0XG

Migrate to 12.1 latest

 

12.0XH

Migrate to 12.1 or later

 

12.0XI

Migrate to 12.1 or later

 

12.0XJ

Migrate to 12.1 latest

 

12.0XK

Migrate to 12.2 latest

 

12.0XL

Migrate to 12.2 latest

 

12.0XM

Migrate to 12.1 or later

 

12.0XN

Migrate to 12.1 latest

 

12.0XP

Vulnerable; contact TAC

 

12.0XQ

Migrate to 12.1 or later

 

12.0XR

Migrate to 12.2 latest

 

12.0XS

Migrate to 12.1E latest

 

12.0XT

Vulnerable; contact TAC

 

12.0XU

Vulnerable; contact TAC

 

12.0XV

Migrate to 12.1 or later

 

Affected 12.1-Based Release

Rebuild

Maintenance Release

12.1

 

12.1(26)

12.1AA

Migrate to 12.2 latest

 

12.1AX

12.1(14)AX3

 

12.1AY

Migrate to 12.1(22)EA2 or later

 

12.1AZ

Migrate to 12.1(22)EA2 or later

 

12.1DA

Vulnerable; contact TAC

 

12.1DB

Migrate to 12.3(4)T11 or later

 

12.1DC

Migrate to 12.3(4)T11 or later

 

12.1E

12.1(22)E3

 

12.1(23)E2

 
 

12.1(26)E

12.1EA

12.1(22)EA2

 

12.1EC

Vulnerable; contact TAC

 

12.1EO

Vulnerable; contact TAC

 

12.1EV

Migrate to 12.2S latest

 

12.1EW

Migrate to 12.2(18)EW2 or later

 

12.1EX

Migrate to 12.1E latest

 

12.1EY

Migrate to 12.1E latest

 

12.1T

Migrate to 12.2 or later

 

12.1XA

Migrate to 12.2 or later

 

12.1XB

Migrate to 12.2 or later

 

12.1XC

Migrate to 12.2 or later

 

12.1XD

Migrate to 12.2 or later

 

12.1XE

Migrate to 12.1E latest

 

12.1XF

Migrate to 12.3 or later

 

12.1XG

Migrate to 12.3 or later

 

12.1XH

Migrate to 12.2 or later

 

12.1XI

Migrate to 12.2 latest

 

12.1XJ

Migrate to 12.3 or later

 

12.1XL

MMigrate to 12.3 or later

 

12.1XM

Migrate to 12.3 or later

 

12.1XP

Migrate to 12.3 or later

 

12.1XQ

Migrate to 12.3 or later

 

12.1XR

Migrate to 12.3 or later

 

12.1XT

Migrate to 12.3 or later

 

12.1XU

Migrate to 12.3 or later

 

12.1XV

Vulnerable; contact TAC

 

12.1YA

Migrate to 12.3 or later

 

12.1YB

Migrate to 12.3 or later

 

12.1YC

Migrate to 12.3 or later

 

12.1YD

Migrate to 12.3 or later

 

12.1YE

Migrate to 12.3 or later

 

12.1YF

Migrate to 12.3 or later

 

12.1YH

Migrate to 12.3 or later

 

12.1YI

Migrate to 12.2(2)YC or later

 

12.1YJ

Migrate to 12.1(22)EA2 or later

 

Affected 12.2-Based

Rebuild

Maintenance Release

12.2

 

12.2(27)

12.2B

Migrate to 12.3(4)T11 or later

 

12.2BC

Vulnerable; contact TAC

 

12.2BW

Migrate to 12.3 or later

 

12.2BX

Migrate to 12.3(7)XI3 -- Available 2/15/05

 

12.2BY

Migrate to 12.3(4)T11 or later

 

12.2BZ

Migrate to 12.3(7)XI3 -- Available 2/15/05

 

12.2CZ

Vulnerable; contact TAC

 

12.2DA

Vulnerable; contact TAC

 

12.2DD

Migrate to 12.3(4)T11 or later

 

12.2DX

Migrate to 12.3(4)T11 or later

 

12.2EW

12.2(18)EW2

 
 

12.2(25)EW

12.2JK

12.2(15)JK2

 
 

12.2MB

Migrate to 12.2(25)SW or later

 

12.2MC

Migrate to 12.3(11)T or later

 

12.2MX

Migrate to 12.3(8)T5 or later

 

12.2S

 

12.2(25)S

12.2(14)S13

12.2(18)S8

 

12.2(20)S7

 

12.2SE

12.2(20)SE3

 

12.2SU

12.2(14)SU2

 

12.2SW

Migrate to 12.2(25)SW

 

12.2SX

Migrate to 12.2(17d)SXB5

 

12.2SXA

Migrate to 12.2(17d)SXB5

 

12.2SXB

12.2(17d)SXB5

 

12.2SXD

12.2(18)SXD2

 

12.2SY

Migrate to 12.2(17d)SXB5

 

12.2SZ

Migrate to 12.2(25)S or later

 

12.2T

12.2(15)T15

 

12.2XA

Migrate to 12.3 or later

 

12.2XB

Migrate to 12.3 or later

 

12.2XC

Migrate to 12.3 or later

 

12.2XD

Migrate to 12.3 or later

 

12.2XE

Migrate to 12.3 or later

 

12.2XF

Vulnerable; contact TAC

 

12.2XG

Migrate to 12.3 or later

 

12.2XH

Migrate to 12.3 or later

 

12.2XI

Migrate to 12.3 or later

 

12.2XJ

Migrate to 12.3 or later

 

12.2XK

Migrate to 12.3 or later

 

12.2XL

Migrate to 12.3 or later

 

12.2XM

Migrate to 12.3 or later

 

12.2XN

Migrate to 12.3 or later

 

12.2XQ

Migrate to 12.3 or later

 

12.2XS

Migrate to 12.3 or later

 

12.2XT

Migrate to 12.3 or later

 

12.2XU

Migrate to 12.3 or later

 

12.2XW

Migrate to 12.3 or later

 

12.2XZ

Migrate to 12.3 or later

 

12.2YA

12.2(4)YA8

 

12.2YB

Migrate to 12.3 or later

 

12.2YC

Migrate to 12.3 or later

 

12.2YE

Migrate to 12.2S or later

 

12.2YF

Migrate to 12.3 or later

 

12.2YG

Migrate to 12.3 or later

 

12.2YH

Migrate to 12.3 or later

 

12.2YJ

Migrate to 12.3 or later

 

12.2YK

Migrate to 12.3T or later

 

12.2YL

Migrate to 12.3T or later

 

12.2YM

Migrate to 12.3T or later

 

12.2YN

Migrate to 12.3T or later

 

12.2YO

Migrate to 12.2(17d)SXB5

 

12.2YP

Migrate to 12.3 or later

 

12.2YQ

Migrate to 12.3(4)T11 or later

 

12.2YR

Migrate to 12.3(4)T11 or later

 

12.2YS

Migrate to 12.3T or later

 

12.2YT

Migrate to 12.3 or later

 

12.2YU

Migrate to 12.3T or later

 

12.2YV

Migrate to 12.3(4)T11 or later

 

12.2YW

Migrate to 12.3(4)T11 or later

 

12.2YX

Migrate to 12.2(14)SU2 or later

 

12.2YY

Migrate to 12.3T or later

 

12.2YZ

Migrate to 12.2(25)S or later

 

12.2ZA

Migrates to 12.2(17d)SXB5 or 12.2(18)SXD2

 

12.2ZB

Migrate to 12.3T or later

 

12.2ZC

Migrate to 12.3T or later

 

12.2ZD

Migrate to 12.3 or later

 

12.2ZE

Migrate to 12.3 or later

 

12.2ZF

Migrate to 12.3(4)T11 or later

 

12.2ZG

Migrate to 12.3(4)T11 or later

 

12.2ZH

Migrate to 12.3(4)T11 or later

 

12.2ZI

Migrate to 12.2(25)S or later

 

12.2ZJ

Migrate to 12.3T or later

 

12.2ZK

12.2(15)ZK6

 

12.2ZL

Migrate to 12.3(7)T7 or later

 

12.2ZN

Migrate to 12.3T or later

 

12.2ZO

Migrate to 12.3 or later

 

12.2ZP

Vulnerable; contact TAC

 

Affected 12.3-Based

Rebuild

Maintenance Release

12.3

12.3(6d)

12.3(9c)

 

12.3(10a)

 
 

12.3(12)

12.3B

12.3(5a)B3

 

12.3BC

12.3(9a)BC1

 

12.3BW

Migrate to 12.3(7)T7 or later

 

12.3T

12.3(4)T11

 

12.3(7)T7

 

12.3(8)T5

 
 

12.3(11)T

12.3XA

Migrate to 12.3(7)T7 or later

 

12.3XB

Migrate to 12.3(8)T5 or later

 

12.3XC

12.3(2)XC3

 

12.3XD

12.3(4)XD4

 

12.3XE

12.3(2)XE1

 

12.3XF

Migrate to 12.3(11)T or later

 

12.3XG

Migrate to 12.3(11)T or later

 

12.3XH

Migrate to 12.3(11)T or later

 

12.3XI

12.3(7)XI3 - Available 2/15/05

 

12.3XJ

Vulnerable; contact TAC

 

12.3XK

Vulnerable; contact TAC

 

12.3XL

Vulnerable; contact TAC

 

12.3XN

Vulnerable; contact TAC

 

12.3XQ

12.3(4)XQ1 Release date not yet determined

 

12.3XR

Vulnerable; contact TAC

 

12.3XS

12.3(7)XS2

 

12.3XU

12.3(8)XU4

 

12.3XV

Migrate to 12.3(11)T or later

 

12.3XX

12.3(8)XX1

 

12.3YA

12.3(8)YA1

 

12.3YC

Vulnerable; contact TAC

 

12.3YD

Vulnerable; contact TAC

 

12.3YE

Migrate to 12.3(4)T11 or later

 

12.3YF

Vulnerable; contact TAC

 

12.3YH

Vulnerable; contact TAC

 

12.3YJ

Vulnerable; contact TAC

 

12.3YL

Vulnerable; contact TAC

 

Workarounds

The effectiveness of any workaround 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 is the most appropriate for use in the intended network before it is deployed.

The use of networking best practices techniques can greatly reduce the probability of a network infrastructure attack. Best practices that may reduce risk in this case include:

BGP MD5

Under normal circumstances, due to inherent security factors in the TCP protocol, such as sequence number checks, it is difficult, but possible to forge an appropriate packet to exploit this problem. Configuring your Cisco IOS device for BGP MD5 authentication greatly increases the work necessary to forge a valid packet from a remote peer. This will not protect your peering session if a valid BGP peer generates an invalid packet.

This can be configured as shown in the following example:

router(config)# router bgp 
 router(config-router)# neighbor <IP_address> password <enter_your_secret_here>

It is necessary to configure the same shared MD5 secret on both peers and at the same time. Failure to do so will break the existing BGP session and the new session will not get established until the exact same secret is configured on both devices. For a detailed discussion on how to configure BGP, refer to the following document:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_configuration_guide_chapter09186a00800ca571.html

Once the secret is configured, it is prudent to change it periodically. The exact period must fit within your company security policy but it should not be longer than a few months. When changing the secret, again it must be done at the same time on both devices. Failure to do so will break your existing BGP session. The exception is if your Cisco IOS software release contains the integrated CSCdx23494 ( registered customers only) fix on both sides of the connection. With this fix, the BGP session will not be terminated when the MD5 secret is changed only on one side. The BGP updates, however, will not be processed until either the same secret is configured on both devices or the secret is removed from both devices.

Infrastructure Access Control Lists (iACLs)

Although it is often difficult to block traffic transiting your network, it is possible to identify traffic that should never be allowed to target your infrastructure devices and block that traffic at the border of your network. Infrastructure ACLs are considered a network security best practice and should be considered as a long-term addition to good network security as well as providing some added protection for this specific vulnerability. The white paper entitled "Protecting Your Core: Infrastructure Protection Access Control Lists" presents guidelines and recommended deployment techniques for infrastructure protection ACLs:

http://www.cisco.com/warp/public/707/iacl.html

Workarounds for IOS XR

Users of Cisco IOS XR can avoid exposure to this vulnerability by not enabling 'debug bgp' at a level of 'warning' or anything more verbose and not logging bgp neighbor state changes.

Obtaining Fixed Software

Cisco has made free software available to address this vulnerability for affected customers. 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/public/sw-license-agreement.html, or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml.

Do not contact either "psirt@cisco.com" or "security-alert@cisco.com" for software upgrades.

Customers with Service Contracts

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 using Third Party Support Organizations

Customers whose Cisco products are provided or maintained through prior or existing agreement 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 without Service Contracts

Customers who purchase direct from Cisco but who do not hold a Cisco service contract and customers who purchase through third-party vendors but are unsuccessful at obtaining fixed software through their point of sale should get their 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

Have your product serial number available and give the URL of this notice as evidence of your 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 special localized telephone numbers and instructions and e-mail addresses for use in various languages.

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 discovered by Cisco during internal testing.

Status of this Notice: Final

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.


Distribution

This advisory will be posted on Cisco's worldwide website at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20050126-bgp .

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-teams@first.org (includes CERT/CC)
  • bugtraq@securityfocus.com
  • vulnwatch@vulnwatch.org
  • cisco@spot.colorado.edu
  • cisco-nsp@puck.nether.net
  • full-disclosure@lists.netsys.com
  • 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 History

Revision 1.5

2005-March-21

Updated the IOS Software 12.2T available repaired release information in the IOS release table in the Software Versions and Fixes section.

Revision 1.4

2005-February-09

Modifications and additions to the Details section.

Revision 1.3

2005-February-04

Modifications to Software Versions and Fixes Table, Summary, Affected Products, and Details sections.

Revision 1.2

2005-February-01

Additional rebuilds added to 12.2S

Revision 1.1

2005-January-29

Added IOS XR as affected. Minor syntax changes. Modified 12.2ZA migration path.

Revision 1.0

2005-January-26

Initial public release.

Cisco Security Procedures

Complete information on reporting security vulnerabilities in Cisco products, obtaining assistance with security incidents, and registering to receive security information from Cisco, is available on Cisco's worldwide website at http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html. This includes instructions for press inquiries regarding Cisco security notices. All Cisco security advisories are available at http://www.cisco.com/go/psirt.