Some stories about hacking the ATM.
In Lithuanian town Šiauliai students cheated the Swedbank ATM in quite easy way. They inserted their own cards into ATM, entered the sum which was available for those accounts, but when the ATM gave the cash they took only 1 note from the middle of the pack. The ATM thought that cash wasn't taken so it took them back and didn't decrease the account total sum. In that way student stoled about 13000 EUR.
Unfortunately the end of the story is not so wise. When the bank suspected the fraud they closed the account. Naive students went to the bank telling that they lost their cards, where they were arrested.
The source is article (in Russian, 18.03.2004) in Baltic internet portal. In the article comments is written that same system was actually applied earlier in Finland. And that this trick you can do only on the old models, the new ones decrease total sum anyway and the "forgotten" cash is going to the special compartment. Later workers count these "forgotten cash" and verify the info. If it match - then they increase the sum.
In the same comments is written one more interesting detail: if you request sum which is 10 times larger than you have in you account, then ATM is giving you cash sum which it has. In way like "ATM has only 10000 EUR".
And the newer one story about hacking the ATM in Estonia.
The left one is correct and the right one is with hacking devices on it:
Above the screen there is a camera which simply records the PIN code:
In the card reader area is an additional card reader, which copies some info from inserted card magnetic tape:
Later cheater copied info from the inserted card to the blank card and simply used the fake card and PIN code to take cash from random ATM.
Source articles (in Estonian): Postimees, Delfi.