It started when he changed my name in my outlook address book to be spelt wrong. This really annoyed me, so I repeated the favour on his machine, except I put in an extra name into his address book (his middle name which he doesn't like).
So then he changed my name in the bug-logging software so that everyone would see it. And then he logged into my work's webmail and sent emails to everyone that looked like they were coming from me.
So I couldn't take all of this lying down.
I then changed his computer so that when he entered google.com it actually took him to yahoo.com. Very annoying when you want to check gmail or search for anything.
After changing the file on his computer I had to wait another 2 more days for him to reboot for the change to take effect. And then one day... all of a sudden.. I hear.. "hey, google's been hacked!"
Queue incessant giggling from my corner of the office.
So how did I do it?
Well, you need to edit this file:
I did a "ping www.yahoo.com", which gave me yahoo's IP address.
Then I added the following two lines to his hosts file:
I first tried this on my machine, and it didn't work. I tried a "ipconfig /flushdns" but it still wasn't taking me to yahoo.
However, if you try to go to gmail.google.com it brought up an error message, because firefox thought that the security certificate was coming from yahoo. So I figured that was enough of a problem for my collegue to deal with.
The next thing that I needed to do was to edit that file on his machine. Fortunately we all have domain admin privileges, so I could just browse to his machine and edit the file. However, I couldn't remember the name of his machine. So I looked at an email that I got previously from him, and had a look at the header info. Buried in there somewhere was his machine name + ip. Bingo!