Cyber crime forum advertises financial malware that uses stealthy I2P communications

A new financial malware program that communicates with attackers over the I2P (Invisible Internet Project) anonymity network is for sale on a Russian cybercrime forum.

The malware is called i2Ninja and uses the I2P network as a C&C (command-and-control) channel, according to security researchers from Trusteer, who claim to have seen the announcement.

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I2P is a distributed peer-to-peer network that uses several layers of encryption to allow secure and anonymous communication, establishing what is known as a darknet, a separate network within the Internet. Like Tor, a similar but more popular darknet, I2P was designed to allow various services to run and be accessible only from within the network itself.

Anonymous websites running on .i2p pseudo-domains can only be accessed through EepProxy, a proxy program that connects a browser to the I2P network.

According to the announcement posted by the i2Ninja creator, the malware has most of the features found in other financial malware. For example, it can steal information entered into Web forms and inject rogue content into HTTP and HTTPS sessions in Internet Explorer, Firefox and Chrome. It can also steal log-in credentials from 33 FTP clients and some of the most popular online poker clients.

For botnet operators, using darknets like Tor or I2P provides considerable benefits. First, the traffic between the malware and the command server cannot be easily blocked by intrusion prevention systems or firewalls because it’s encrypted, said Dmitry Tarakanov, malware researcher at antivirus vendor Kaspersky Lab, Thursday via email.

Blocking this malicious traffic would mean blocking all I2P or Tor traffic because extracting the exact destination from such a network packet in order to only block connections to a particular address is impossible, Tarakanov said. In addition, by hiding their C&C servers inside the I2P or Tor networks attackers can make it much harder for security researchers to find and take down those servers, he said.

There have already been cases of malware using Tor as a C&C channel, like the case of the Mevade botnet, which was responsible for a significant increase in the number of Tor users in August.

It’s not clear whether i2Ninja has peer-to-peer capabilities like the Gameover or Hlux/Kelihos botnets in which infected computers can relay information and commands directly to each other. If that’s the case, it might be hard to take down botnets based on this malware, Tarakanov said.

It’s not known if i2Ninja is already being used to infect computers. Trusteer based its report on the cybercrime forum announcement and there are no sample hashes that would help antivirus companies search for the malware in their databases.

Since i2Ninja is being sold to other cybercriminals, it will probably be distributed using the usual methods for this type of malware: spam emails, drive-by-download attacks launched from websites infected with exploit kits and by direct installation through existing botnets, Tarakanov said.