A variant of the ZeuS banking trojan is targeting mobile phone users who rely on their handsets to get enhanced, two-factor authentication from ING Bank Slaski in Poland, a security blogger said on Monday.
The ZeuS man-in-the-mobile attacks appear to similar to those that hit Spain in September, researchers from antivirus provider F-Secure said. Both attacks attempt to steal so-called mTANs, short for mobile transaction authentication numbers, which an increasing number of European banks are using to provide enhanced authentication to online customers. Financial institutions send the one-time passwords in text messages. The secondary passcodes are needed to login to online accounts.
The ZeuS Mitmo injects a fraudulent field into webpages that prompts users for their cellphone number and the type of handset they use. The criminals behind the operation then send the user an SMS message containing a link to malware that's customized to their Symbian or Blackberry phone. The malware automatically sends all mTANs sent to the handset to the ZeuS operators.
Security blogger Piotr Konieczny, who wrote about the attacks here, said the malware doesn't target iPhones. There was no mention of Android-based phones.
The attacks are a potent reminder of the cat-and-mouse game that's regularly played between criminal enterprises and the financial institutions they prey on. ING tuned to mTANs as a means to combat keyloggers ZeuS and other trojans use to compromise their customers' accounts. ZeuS is now attempting to strike back with a mobile version of the malware.
Google recently introduced one-time passwords that are similar to mTANs except they are used to provide two-factor authentication for Gmail account holders. ®