The Citadel trojan is being pulled underground with fears of a law enforcement crackdown.
Citadel, built on the shoulders of Zeus, was one of the most advanced and quality trojans available with a sale price of around $2500.
It was famous for being the first crimeware kit to include a Customer Relationship Management (CRM) module where clientele could request new features from Citadel’s team of software developers.
Citadel’s creators have now announced the trojan will be pulled from the public Russian underground market, to be likely only sold to users whose reputation existing customers have vouched for.
“By selling less they can keep the trojan from being all too widely-spread”, RSA’s research labs wrote.
Selling on the open market attracts law enforcement and gives white hat researchers access to reverse-engineer the software, forcing Citadel’s developers to tweak its functions.
Citadel’s developers were accessories to the crimes committed by their botmaster customers but RSA points out that those behind other crimeware kits like Spyeye and rival Ice have to date escaped arrest.
“…we are seeing the Citadel’s team already taking measures to go deeper underground for their own safety.”
That anti-emulator would detect sandboxes and, rather than terminate operation like other trojans, would mimic normal functionality but fake connection to botnets in hopes of throwing researchers off the scent.