Bank data-stealing Trojan infects hundreds of thousands of PCs - researcher

A "tremendous" amount of financial data has been stolen by a Trojan that has infected hundreds of thousands of corporate and personal PCs, according to information security specialist SecureWorks.

Clampi, also known as Ligats, Ilomo or Rscan, has spread across Microsoft networks in a "worm-like fashion" and is "one of the largest and most professional thieving operations on the Internet" says Joe Stewart, director of malware research at SecureWorks' counter threat unit.

Once it has infected a PC, the Trojan monitors Web sessions to see if one of 4500 targeted sites are visited. If a victim uses one of these sites - which include those of banks, credit card companies, stock brokerages and insurance firms - it captures sensitive information such as usernames, passwords and PINs.