
Anti-virus vendor Sophos detected the rootkit as Troj/RKProc-Fam and other components as the Troj/Keylog-GO Trojan horse last year.
However, recently Sophos' labs have found that the malware has moved to now atatcking companies as well as home users.
Graham Cluley, senior technology consultant for Sophos said the malware sent out a clear message to online gamblers that "just like online bankers, they need to take care over their computer's security."
Once installed the malicious software attempts to steal usernames and passwords from visitors to online gambling websites.
The Trojan horse, known as RBCalc, was distributed on a website offering articles and tools for online poker players, installing a rootkit and other malicious components onto infected computers.