Vulnerability Note VU#929656

BGP implementations do not properly handle UPDATE messages

Overview

BGP implementations from multiple vendors including Juniper may not properly handle specially crafted BGP UPDATE messages. These vulnerabilities could allow an unauthenticated, remote attacker to cause a denial of service. Disrupting BGP communication could lead to routing instability.

I. Description

The Border Gateway Protocol (BGP, RFC 4271) is a widely used inter-Autonomous System routing protocol. BGP communication among peer routers is critical to the stable operation of the internet. Multiple vendors BGP implementations do not properly handle specially crafted BGP UPDATE messages. A vulnerable BGP implementation could drop sessions when processing crafted UPDATE messages. A persistent attack could lead to routing instability (route flapping). To affect a BGP session, an attacker would need to succesfully inject a specially crafted packet into an existing BGP session or the underlying TCP session (179/tcp). In other words, the attacker would need to have a valid, configured BGP session or be able to spoof TCP traffic.

This vulnerability was first announced as affecting Juniper routers. Further investigation indicates that other vendors are affected by the same or similar issues. Please see the Systems Affected section below.

II. Impact

A remote attacker could cause a denial of service by injecting a specially crafted BGP UPDATE message into a legitimate BGP session. An attacker with a configured BGP session could attack targets several BGP hops away, or an attacker could spoof TCP traffic.

III. Solution

Upgrade

Upgrade your BGP software as appropriate. Please see the Systems Affected section below for information about specific vendors.

In order to send a specially crafted BGP UPDATE message, an attacker must have or spoof a valid BGP connection. The following workarounds and other BGP security techniques may provide some defense against spoofed connections, however spoofed connections may not be a realistic threat scenario, and the more correct resolution is to upgrade.

Authenticate BGP Traffic

Use TCP MD5 to authenticate BGP traffic (RFC 2385). Only allow BGP traffic from authorized peers. It is generally recognized that TCP MD5

Restrict BGP Access

Restrict BGP network access to authorized peers. If possible, run BGP on management networks, not transit networks. More information about BGP security (including secure BGP configuration templates) is available from the Team Cymru Reading Room.

Systems Affected

Vendor	Status	Date Notified	Date Updated
3com, Inc.	Unknown	2007-12-13	2007-12-13
ACCESS	Not Vulnerable		2008-05-20
Alcatel	Unknown	2007-12-13	2007-12-13
AT&T	Unknown	2007-12-13	2007-12-13
Avaya, Inc.	Unknown	2007-12-13	2007-12-13
Avici Systems, Inc.	Vulnerable	2007-12-13	2008-04-28
Century Systems Inc.	Vulnerable		2008-04-28
Charlotte's Web Networks	Unknown	2007-12-13	2007-12-13
Check Point Software Technologies	Unknown	2007-12-13	2007-12-13
Cisco Systems, Inc.	Not Vulnerable	2007-12-13	2008-05-06
D-Link Systems, Inc.	Unknown	2007-12-13	2007-12-13
Data Connection, Ltd.	Unknown	2007-12-13	2007-12-13
Extreme Networks	Vulnerable	2007-12-13	2009-06-08
F5 Networks, Inc.	Unknown	2007-12-13	2007-12-13
Force10 Networks, Inc.	Not Vulnerable	2007-12-13	2008-02-22
Foundry Networks, Inc.	Not Vulnerable	2007-12-13	2008-04-28
Fujitsu	Not Vulnerable		2008-04-28
GNU Zebra	Not Vulnerable		2008-05-20
Hitachi	Vulnerable	2007-12-13	2008-08-12
Hyperchip	Unknown	2007-12-13	2007-12-13
IBM Corporation	Unknown	2007-12-13	2007-12-13
Ingrian Networks, Inc.	Unknown	2007-12-13	2007-12-13
Intel Corporation	Unknown	2008-04-08	2008-04-08
IP Infusion, Inc.	Not Vulnerable	2008-02-22	2008-05-20
Juniper Networks, Inc.	Vulnerable	2008-01-16	2008-05-01
Lucent Technologies	Unknown	2007-12-13	2007-12-13
Luminous Networks	Unknown	2007-12-13	2007-12-13
Multinet (owned Process Software Corporation)	Unknown	2007-12-13	2007-12-13
Multitech, Inc.	Unknown	2007-12-13	2007-12-13
NEC Corporation	Vulnerable		2008-06-06
Network Appliance, Inc.	Not Vulnerable	2007-12-13	2007-12-14
NextHop Technologies, Inc.	Unknown	2007-12-13	2007-12-13
Nokia	Unknown	2008-04-08	2008-04-08
Nortel Networks, Inc.	Unknown	2007-12-13	2007-12-13
OpenBSD	Unknown	2008-02-22	2008-02-22
Quagga	Not Vulnerable	2008-02-22	2008-04-28
Redback Networks, Inc.	Unknown	2007-12-13	2007-12-13
Riverstone Networks, Inc.	Unknown	2007-12-13	2007-12-13
Sun Microsystems, Inc.	Not Vulnerable	2008-02-22	2008-04-28
Wind River Systems, Inc.	Unknown	2007-12-13	2007-12-13
Yamaha Corporation	Vulnerable		2008-04-28
ZyXEL	Unknown	2007-12-13	2007-12-13

References

http://www.kb.cert.org/vuls/id/415294
http://tools.ietf.org/html/rfc4271
http://www.iana.org/assignments/bgp-parameters
http://tools.ietf.org/html/rfc2385
http://tools.ietf.org/html/rfc2439
http://secunia.com/advisories/28100/
http://nvd.nist.gov/nvd.cfm?cvename=CVE-2007-6372
https://www.juniper.net/alerts/viewalert.jsp?actionBtn=Search&txtAlertNumber=PSN-2007-12-008&viewMod%20e=view
http://isc.sans.org/diary.php?storyid=3748
https://puck.nether.net/pipermail/juniper-nsp/2007-December/009294.html
https://puck.nether.net/pipermail/juniper-nsp/2007-December/009299.html
http://jvn.jp/cert/JVNVU929656/index.html
http://osvdb.org/show/osvdb/39157
http://www.securityfocus.com/bid/26869
http://www.frsirt.com/english/advisories/2007/4223
http://securitytracker.com/alerts/2007/Dec/1019100.html
http://www.team-cymru.org/?sec=13&opt=28
http://secunia.com/advisories/30028/

Credit

Thanks to members of the Juniper Security Incident Response Team for help in preparing this document.

This document was written by Art Manion.

Other Information

Date Public:	2007-12-12
Date First Published:	2008-05-06
Date Last Updated:	2009-06-09
CERT Advisory:
CVE-ID(s):	CVE-2007-6372
NVD-ID(s):	CVE-2007-6372
US-CERT Technical Alerts:
Metric:	24.49
Document Revision:	57

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Produced 2008 by US-CERT, a government organization
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