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Sophos: Citadel Malware Targeting Canadian Banks and POS Systems

According to a report from Sophos, the Citadel crime kit is branching out from its Zeus roots, and the criminals responsible for the botnet’s operations are opting to take quality over quantity when it comes to victims.

Citadel has been in operation for a while now, as the kit came about shortly after the source code for the Zeus malware was leaked to the web. Unlike other clones, however, Citadel has earned a reputation for being moneymaking system in the criminal underworld.

Citadel MalwareLike Zeus, Citadel targets financial data. Often, the goal is to take as much data as possible from a victim’s system. With the influx of data, a massive quantity if you will, the odds are in the criminal’s favor that they will hit pay dirt. However, Sophos says that a new variant of Citadel is being more selective.

“SophosLabs have been tracking one particular strain of Citadel that is much more specific about its targets, aiming to capture higher quality data at the sacrifice of quantity,” the security firm blogged

“The configuration file that this sample downloads shows that it is targeting a small number of financial institutions all based in Canada including one company that processes payments from Point Of Sale devices and credit and debit cards.”

The data is captured via screenshots and keylogging, and it would see the goal is to reach a higher level of return on each record obtained. While examining the sample, Sophos noted that the targeted design was named “test,” suggesting that similar operations are yet to come.

“It also highlights a worrying trend: that crimeware kit owners are becoming more adept at using the kits they have purchased, allowing them to tailor attacks for specific high return targets, meaning that a single breach could have devastating consequences for a victim organization.”

Last August, Trusteer discovered an attack utilizing Citadel that targeted an enterprise VPN belonging to a major international airport, which was targeting airport employees – not passengers – in order to steal the credentials needed to access the airport’s VPN and internal applications.

Last October, RSA researchers discovered that developers behind the Citadel Trojan had added a new feature known as "Dynamic Config" that enables botmasters to have quicker interactions with infected victims through browser injection technology.

Interestingly, in December 2012, SecurityWeek’s Brian Prince reported that RSA researchers discovered the Citadel Trojan was slowly being pulled from underground markets after a spat between Citadel's developer, known as "Aquabox", and a buyer led to him being banned from one of the largest online crime communities Citadel was ever a part of.

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Steve Ragan is a security reporter and contributor for SecurityWeek. Prior to joining the journalism world in 2005, he spent 15 years as a freelance IT contractor focused on endpoint security and security training.