400 Banks On Trojan Hit List

Over at Symantec they are warning users of a new Trojan virus that is targeting over 400 banks. According to the post the Trojan can intercept transactions between two parties to gather personal information. In the statement it reads:

This Trojan downloads a configuration file that contains the domain names of over 400 banks. Not only are the usual large American banks targeted but banks in many other countries are also targeted, including France, Spain, Ireland, the UK, Finland, Turkey — the list goes on.

The ability of this Trojan to perform man-in-the-middle attacks on valid transactions is what is most worrying. The Trojan can intercept transactions that require two-factor authentication. It can then silently change the user-entered destination bank account details to the attacker’s account details instead. Of course the Trojan ensures that the user does not notice this change by presenting the user with the details they expect to see, while all the time sending the bank the attacker’s details instead. Since the user doesn’t notice anything wrong with the transaction, they will enter the second authentication password, in effect handing over their money to the attackers. The Trojan intercepts all of this traffic before it is encrypted, so even if the transaction takes place over SSL the attack is still valid. Unfortunately, we were unable to reproduce exactly such a transaction in the lab. However, through analysis of the Trojan’s code it can be seen that this feature is available to the attackers.

The Trojan does not use this attack vector for all banks, however. It only uses this route when an easier route is not available. If a transaction can occur at the targeted bank using just a username and password then the Trojan will take that information, if a certificate is also required the Trojan can steal that too, if cookies are required the Trojan will steal those. In fact, even if the attacker is missing a piece of information to conduct a transaction, extra HTML can be added to the page to ask the user for that extra information. (In the example below the user is asked to enter their encryption key, in addition to the regular information.)

As always your best line of defense is to make sure your anti-virus program has the latest updates. You may also wish to check with your banking institution to see what other safeguards they may recommend as well. Be safe.

Full report is here.

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