Rating:

The task is a usb pcap where two files were transfered. The trick was to take
each odd packet number and take 0x708 of each to create the first file, use the
even for the 2nd file. We were left with two Libreoffice ods file. In the 2nd
one, we found a table and a weird alphabetic suite which used against the table
give us the flag.

Original writeup (http://duksctf.github.io/NDH2016-catch-me-if-you-can/).