Little Suzie started learning C. She created
a simple program that echo’s back
whatever you input. Here is the binary file.
The vampire came across this service on
the internet. nc hack.bckdr.in 8002.
Reports say he found a flag. See if you can
get it.

Original writeup (http://geeksspeak.github.io/blog/2015/04/03/backdoor-ctf-2015-echo-writeup/).