The programs are reportedly attacking computers across western Europe, grabbing online banking information and sending it back to a third party.
One of the programs hijacks passwords, while the other conceals itself behind a rootkit. Trojans are malicious programs that masquerade as harmless software.
Ramses Martinez, director at security firm iDefense, told CNET News that information is probably stored by web criminals or sold to gangs who then exploit it.
The two malicious Trojan horses have targeted banks in the UK, Germany and Spain. One program injects malicious HTML into fields when PC users visit a bank website, using a keylogger to hijack PIN codes and account numbers as they are entered.
The Trojan uses a flaw in Microsoft Internet Explorer and victims must visit a website in order for their system to become infected, according to Symantec.
The second malicious program is hidden alongside a rootkit and infects PCs, directing them to infected websites and accessing passwords and usernames that have been entered previously on the computer, Sana Labs warns.