Atmos, the Citadel Trojan successor is in the wild

Security experts from the Heimdal Security firm are issuing an alert on the Atmos malware which is the successor of the dreaded Citadel Trojan.

Months ago, the author of the dreaded Citadel malware was sentenced to prison, but in the same period, a new improved variant resurged in the wild. The new strain of Citadel malware, called Atmos, is now targeting banks in France and it was also served with the Teslacrypt ransomware.

Atmos has been active since late 2015, but the experts have discovered it in the wild only recently.

Citadel was first spotted in 2011, its authors used the code of the ZeuS Trojan code to create the new threat.

“Dimitry Belorossov, a/k/a Rainerfox, has been sentenced to four years, six months in prison following his guilty plea for conspiring to commit computer fraud. Belorossov distributed and installed Citadel, a sophisticated malware that infected over 11 million computers worldwide, onto victim computers using a variety of infection methods.” stated the announcement issued by the FBI.

“In 2012, Belorossov downloaded a version of Citadel, which he then used to operate a Citadel botnet primarily from Russia. Belorossov remotely controlled over 7,000 victim bots, including at least one infected computer system with an IP address resolving to the Northern District of Georgia. Belorossov’s Citadel botnet contained personal information from the infected victim computers, including online banking credentials for U.S.-based financial institutions with federally insured deposits, credit card information, and other personally identifying information.”

The Citadel malware is a powerful data stealer, it was mainly used in banking frauds, but it has the ability to carry out a large number of fraudulent operations.

In the second half of 2012, security experts began to see Citadel variants designed to breach networks of  government and private companies.

On June 5 2013, the Microsoft Digital Crimes Unit announced that its experts were working with the FBI to shut down the Citadel botnet and to arrest its operators.

Today security experts at Heimdal security are issuing an alert on the Citadel successor, Atmos.

The researchers discovered that the new Citadel variant was heavily modified respect its predecessors. It utilizes the same web injection mechanisms implemented by ZeuS, a circumstance that leads the experts into belief that it was designed with the same intent.

The researchers confirmed that only a few sample was discovered in the wild targeting French banks.

Giving a look at the technical details shared by the Heimdal Security, we note that C&C servers are located in Vietnam, Canada, Ukraine, Russia, the US and Turkey and the overall Atom botnet is already composed of more than 1000 machines.

Below the list of Indicators of Compromise tied to the new Atmos Trojan:

http://iguana58[.]ru/plugins/system/anticopy/adobe[.]exe
http://tehnoart[.]co/sr[.]exe
http://3dmaxkursum[.]net/tmp/sys/config[.]exe
http://iguana58[.]ru/plugins/system/anticopy/adobe[.]exe
http://mareikes[.]com/wp-includes/pomo/svhost[.]exe
http://mareikes[.]com/wp-includes/pomo/server[.]exe

I invite you to read the Heimdal’s Alert, Atmos have to be considered a very dangerous threat, especially for the private industry.

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Pierluigi Paganini 

(Security Affairs – Atmos trojan, Citadel)