My routers are all affected by the recent IOS vulnerability. I have implement the access-list recommonded by Cisco on my Internet router. I also have a internal router but i have not apply any work around on this router as there are a lot of application/service within my LAN. If i were to implement the access-list, i will need to test all the service. As i will be having a major network migration in a month time, i was thinking to upgrde the IOS than.
How vulnerable is my internal router when i have the internet router put up with the recommanded access-list. How does the specifically crafted IPv4 packets work? Furthermore, my internal router is private ip address. Will the specifically crafted IPv4 packets slip throught my Internet router and reach my internal router since i already have the 1st level block and assuming that there won't be any internal DoS.
The packet must have a destination address of the router. If your router is using non-routable addresses you are only vulnerable from the inside of your network. The access-lists only block seldom used protocols. If you are not sure if they are in use on your network create the access-list on the router and do not apply it to an interface, then after a few days type "show ip access-list" and look for hits on that access-list.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...