So word spread pretty quickly about the wireshark bugs being thrown around Defcon 20 CTF. After I got my hands on acme pharms packet capture I quickly set out to recover the evil packets and weaponize them :)
After unpacking the tarball I found a pcap file that crashed my Wireshark(version 1.8.1), sf1-37.pcap
My copy of Wireshark was compiled without any debug information so I quickly grabbed the latest source from http://www.wireshark.org and recompiled it. After opening the pcap again in a Wireshark session running under gdb I got the name of the source file and even the offending line of code.
The source of the crash is a division by zero. Perfect for crashing Wireshark.
I wanted to examine this packet in Wireshark so I needed to write a patch and recompile.
I rewrote the line
I was able to quickly hunt down the offending packets in wireshark. There are several hundred of them. They are easily identifiable because wireshark says they need l337:
I exported the first one that caught my fancy to see if I could induce a wireshark crash with a single packet.
As it turns out, you can. Sweet. This makes my life easy, I can strip out the application layer data from this packet to write a POC.
Writing a script to exploit this bug is easy. I used scapy, a third party packet crafting python library to build an IPv6 packet with one argument for a destination IPv6 address and send it.