First released on January 2012 into the Russian-speaking underground, the Citadel crimeware became extremely popular with online criminals in a very short time due to the continuos updating and the possibility for customers to contact the developers and ask for new capabilities via the malware's CRM.
"Sold for $2,500 for a kit with added plugins going for an average of $1,000 each, Citadel developers are making good money with this banking Trojan," RSA researchers point out.
But, as many other malware developers before them, they seem increasingly concerned with the attention their malware and the criminals using it are getting from law enforcement agencies, and this could explain the announcement.
Still, it appears that existing customers will still get the upgrades, and be able to vouch for new customers.
"While this could be a marketing stint designed to create urgency and generate more sales, Citadelís developers could also be seeing the need to slow down sales. By selling less they can keep the Trojan from being all too widely-spread, which will invariably lead to more sampling and research and cause them the need to rework its evasion mechanisms," say the researchers.
"Additionally, more customers also means more support, more underground buzz, and eventually, like Zeus, SpyEye, and Carberp ó more cybercrime arrests linked with using Citadel."