Networking/Computing Tips/Tricks

I want to continue my articles on IPv6 Security with an example of IPv6 Fragmentation.  Needing some training on IPv6 or IPv6 Security - check out our courses here.

That said, one way to possibly bypass any security functions in a router or firewall may be to send fragmented packets through the device.  This has been shown to work in defeating RA Guard for example.  You can read more about that here.

Now, getting IPv6 packets with any extension headers on them at all to pass across the Internet is darned near impossible.  See the RFC that reported these findings here.

So to observe this phenomena, in our IPv6 Security class we use a closed lab system.  Then we use an IPv6 attack tool to create the packets and blast them at end user systems/servers/routers to see what happens!

Using Wireshark, here is a brief view of what the attack looks like:

IPv6Fragmentation.pcapng 001

We can see the Fragmentation Extension header indication: Next Header = 44

Then we see the fragmentation header present.  What is cool (kudos to Wireshark here), is that as with IPv4 the Wireshark Expert annotates the dissection with an indication/hyperlink to the point of reassembly, and then actually does the reassembly, like the end user station would do, to verify the fragmentation process.

What could this attack do?  Well, it depends.  It simply could be a throughway past any detection systems.  It could consume CPU, leading to a Denial of Service.  It could indicate that the network is tossing these type of extension headers, which means we may want to create a more complex packet to get into the network.

You will note we are using our IPv6 default profile - it can be found in our profile repository here.

And, if you would like a copy of this .pcap-ng file for your own self study, you can download it here.

 

Comments powered by CComment

Find by Tag

4G Networks 5G Networks 6LoWLAN 6LoWPAN 802.11 802.11ah 802.11ax 802.11ay 802.11az Addressing Analysis Ansible Architecture ARP AToM Baseline BGP Bloom's Taxonomy Broadband Cable cat CellStream Cellular Central Office Cheat Sheet Chrome Cisco Cloud CMD Coloring Rules Computer Consulting Customer Support Data Center Data Networking DHCPv6 DNS Docker Documentation Dublin-Traceroute dumpcap ECMP Ethernet Ethics Evaluation Field Operations Fragmentation G-MPLS GeoIP Git GNS3 Google GQUIC Hands-On History Home Network ICMP ICMPv6 IEEE 802.11p IEEE 802.15.4 India Interface Control Internet IoT IPsec IPv4 IPv6 IRINN IS-IS L2VPN L3VPN LDP Linux LLN LoL M-BGP MAC Macro Microsoft mininet Monitoring MPLS mtr MTU Multicast Name Resolution Netcat Netmiko NetMon netsh Networking Network Science nmap Npcap NSE Observations Online School OpenFlow OSPF OSPFv2 OSPFv3 OSX OTT Paris-Traceroute Parrot PIM PMTU Policy POTS POTS to Pipes PPP Profile Programming Project Management PW3E Python QoS QUIC Remote Desktop Requirements Resume RIP Routing RPL RSVP Rural SDN Security Service Provider Small Business SONET Speed SS7 SSH SSL Subnetting SYSCTL T-Shark TCP TCP/IP Telco Telecom 101 Telecommunications Telephone termshark Testing TLS Tools Traceroute Traffic Engineering Training Travel Tunnel Ubuntu Utility Video Virtualbox Virtualization VoIP VRF VXLAN Wi-Fi Wi-Fi 4 Wi-Fi 5 Wi-Fi 6 Windows Winpcap Wireless Wireless 5G Wireshark Wireshark Tip WLAN Writing Zenmap ZigBee

Twitter Feed