[NEWS] Nortel VPN Router Malformed Packet DoS
SecuriTeam <[email protected]>
| Newsgroups | gmane.comp.security.securiteam |
|---|---|
| Message-ID | <[email protected]> |
The following security advisory is sent to the securiteam mailing list, and can be found at the SecuriTeam web site: http://www.securiteam.com - - promotion The SecuriTeam alerts list - Free, Accurate, Independent. Get your security news from a reliable source. http://www.securiteam.com/mailinglist.html - - - - - - - - - Nortel VPN Router Malformed Packet DoS ------------------------------------------------------------------------ SUMMARY NTA Monitor have discovered a denial of service (DoS) vulnerability in the Nortel VPN Router products (which were previously known as Nortel Contivity) while performing a VPN security test for a customer. The vulnerability allows attackers to send a single malformed IKE packet that in turn will cause the Nortel VPN router to crash. DETAILS Vulnerable Systems: * Nortel VPN router models 1010 * Nortel VPN router models 1050 * Nortel VPN router models 1100 * Nortel VPN router models 600 * Nortel VPN router models 1600 * Nortel VPN router models 1700 * Nortel VPN router models 2600 * Nortel VPN router models 2700 * Nortel VPN router models 4500 * Nortel VPN router models 4600 * Nortel VPN router models 5000 Immune Systems: * Nortel VPN software version V5.05_200 or later The vulnerability is triggered by sending a single IPSec IKE packet with a malformed ISAKMP header. On receipt of this malformed packet, the VPN router will crash immediately. The crash occurs every time such a malformed packet is sent. Sometimes the affected VPN router will automatically reboot (which takes about five minutes), but sometimes it will stay down indefinitely and require manual intervention to restart it. In tests, the VPN router automatically rebooted around 80% of the time, and needed to be manually reset on the remaining 20%. The VPN router does not log the malformed packet, even if the logging level is turned up to maximum. This is probably because the packet causes the router to crash before it has a chance to log it. It is not normally possible to block public inbound access to the IKE service on the VPN router, because it is required for remote access IPSec operation. As IKE uses the UDP transport protocol, the attacker may forge the packet's source IP address to avoid identification, or to prevent the victim from blocking the traffic with ingress filtering. In addition, current IDS/IPS systems will probably not be able to detect the attack, because the malformed packet looks very similar to a normal IKE packet. It is possible for attackers to detect and fingerprint Nortel VPN routers using the IKE fingerprinting techniques that we have previously published in VPN security white papers. Therefore users should not assume that their VPN router is invisible just because it's not published in the DNS and is not running any TCP services. Vendor Status: The vendor has released a fix located at: <http://www130.nortelnetworks.com/cgi-bin/eserv/cs/main.jsp> http://www130.nortelnetworks.com/cgi-bin/eserv/cs/main.jsp ADDITIONAL INFORMATION The information has been provided by <mailto:[email protected]> Roy Hills . The original article can be found at: <http://www.nta-monitor.com/news/vpn-flaws/nortel/nortel-client/> http://www.nta-monitor.com/news/vpn-flaws/nortel/nortel-client/ ======================================== This bulletin is sent to members of the SecuriTeam mailing list. To unsubscribe from the list, send mail with an empty subject line and body to: [email protected] In order to subscribe to the mailing list, simply forward this email to: [email protected] ==================== ==================== DISCLAIMER: The information in this bulletin is provided "AS IS" without warranty of any kind. In no event shall we be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages.