Zeus, also known as Zbot, is a notorious Trojan which infects Windows users and tries to retrieve confidential information from the infected computers. Once it is installed, it also tries to download configuration files and updates from the Internet. The Zeus files are created and customized using a Trojan-building toolkit, which is available online for cybercriminals. Zeus has been created to steal private data from the infected systems, such as system information, passwords, banking credentials or other financial details and it can be customized to gather banking details in specific countries and by using various methods. Using the retrieved information, cybercriminals log into banking accounts and make unauthorized money transfers through a complex network of computers. Zbot/Zeus is based on the client-server model and requires a Command and Control server to send and receive information across the network. The single Command and Control server is considered to be the weak point in the malware architecture and it is the target of law enforcement agencies when dealing with Zeus. To counter this weak point, the latest variant of Zeus/Zbot have included a DGA (domain generation algorithm), which makes the Command and Control servers resistant to takedown attempts. The DGA generates a list of domain names to which the bots try to connect in case the Command and Control server cannot be reached. Zeus/Zbot, known by many names including PRG and Infostealer, has already infected as many as 3.6 million systems in the United States. In 2009, security analysts found that the Zeus spread on more than 70,000 accounts of banks and businesses including NASA and the Bank of America.

Zeus Gameover is a variant of the Zeus family – the infamous family of financial stealing malware – which relies upon a peer-to-peer botnet infrastructure.

The network configuration removes the need for a centralized Command and Control server, including a DGA (Domain Generation Algorithm) which produces new domains in case the peers cannot be reached. The generated peers in the botnet can act as independent Command and Control servers and are able to download commands or configuration files between them, finally sending the stolen data to the malicious servers. Zeus Gameover is used by cybercriminals to collect financial information, targeting various user data from credentials, credit card numbers and passwords to any other private information which might prove useful in retrieving a victim’s banking information. GameOver Zeus is estimated to have infected 1 million users around the world.

Ice IX is a modified variant of Zeus, the infamous banking Trojan, one of the most sophisticated pieces of financial malware out there.

This modified variant is used by cybercriminals with the same malicious purpose of stealing personal and financial information, such as credentials or passwords for the e-mail or the online bank accounts. Like Zeus, Ice IX can control the displayed content in a browser used for online banking websites. The injected web forms are used to extract banking credentials and other private security information. Ice IX, the modified version of Zeus, improved a few Zeus capabilities. The most important one is a defense mechanism to evade tracker sites, which monitor at present most Command and Control servers controlled by Zeus.

Bugat is another banking Trojan, with similar capabilities to Zeus – the notorious data-stealing Trojan – which is used by IT criminals to steal financial credentials.

Bugat targets an infected user’s browsing activity and harvests information during online banking sessions. It can upload files from an infected computer, download and execute a list of running processes or steal FTP credentials. Bugat communicates with a command and control server from where it receives instructions and updates to the list of financial websites it targets. The collected information is sent to the cybercriminal’s remote server. Cybercriminals spreads the malware mostly by inserting malicious links in the e-mails they send to the targeted users. When a user clicks a malicious link, he is directed to a dangerous website where the Bugat executable downloads on the system.

Shylock is a banking malware, designed to retrieve user’s banking credentials for fraudulent purposes.

As soon as it is installed, Shylock communicates with the remote Command and Control servers controlled by the cybercriminals, sending and receiving data to and from the infected PCs. Similar to Zeus Gameover, this malware makes use of a (DGA) Domain generation algorithm which is used to generate a number of domain names that can be used receive commands between the malicious servers and the infected systems.

The Trojan is delivered mostly through drive-by downloads on compromised websites and via malvertising, where malicious code is inserted in adverts that are then placed on legitimate websites. Another popular method of spreading this financial malware is by inserting malicious JavaScript into a web page. This technique produces a pop-up which pushes the user to download a plugin, apparently necessary for the media display on the website.

Torpig is a sophisticated type of malware program designed to harvest sensitive information, such as bank account and credit card information from its victims.

The Torpig botnet – the network of compromised PCs – which are under the control of cybercriminals are the main means for sending spam e-mails or stealing private information or credentials for the online bank accounts. Torpig also uses a DGA (domain generation algorithm) to generate a list of domains names and locate the Command and Control servers used by hackers. Users are typically infected through drive-by downloads; a web page on a legitimate website is modified to ask the user for JavaScript code from a web location controlled by the IT criminals. The infected computers run phishing attacks to obtain sensitive data from its victims.

This malware encrypts your data and displays a message which states that your private information can be decrypted for a sum of money in a limited period of time. Though CryptoLocker can be removed by various security solutions, there isn’t any way yet to decrypt the locked files. CryptoLocker is one of the nastiest pieces of malware ever created. It’s not just because it takes money from you or because it can access your private data, but once it manages to encrypt your information, there is no way for you to decrypt those files. This ransomware is so dangerous because the affected users have their private information disclosed (and taken advantage from) and they also lose the files without having any chance of recovering them. CryptoLocker is a ransomware Trojan which can infect your system in different ways, but usually this happens through the means of an apparently legitimate e-mail attachment, from a well-known company or institution. Because it spreads through e-mail attachments, this ransomware is known to target companies and institutions through phishing attacks.