Does spyware exist for ubuntu?

Someone I know said he had put spyware on my computer. Is he talking crap? I've been using Ubuntu 12.04 for nearly 3 years now and I've never seen any type of spyware, remote keyloggers or RATS (remote access tools) and likewise, backdoors. I've searched several Ubuntu forums and nothing. Other than that Amazon thing. If they even exist, are there antivirus scanners to find, identify and remove them?

There is spyware for every operating system. It is more prevalent for windows than any other operating system because it is used more. There are around 40 known spyware applications for Linux. It is not common but it can happen. As for antivirus this is a list that may help you. Best of luck!

http://opensource-sidh.blogspot.com/2011/10/top-5-anti-virus-for-ubuntu-free.html?m=1

If your friend is familiar with programming, it is possible that he has written a custom spyware script. That is quite easy under Linux, and a common prank to play on unsuspecting friends. Because it is custom, no antivirus program may be able to find it.

Some common places to hide such scripts are the startup files in your home directory, ~/.bashrc etc.

The most straight-forward and reliable way to find such a script would be to run a compare against your latest backup before the incident.

Spyware also exists in browser apps (like those for chrome) so even if you are absolutely sure you have nothing local installed that contains spyware, if you use untrusted webapps, you can be exposed.

Yes, there is spyware-like behavior in several Unix applications.

I worry most about all the applications sending auto-update and metadata lookup requests, often with information about your computer and network activity.

You can use a tool like Wireshark to detect any suspicious network activity and track it down to which applications are sending information. If the upload is not encrypted, Wireshark will even show you the content.