Financially-motivated actors have tried to trick the employees of at least six Russian banks into installing a piece of malware, Symantec reported on Monday.
According to the security firm, the attackers have been using a Trojan dubbed Ratopak, which allows them to open a backdoor on the infected machine and steal data. The threat is capable of logging keystrokes, stealing clipboard data, downloading other malware, and allows hackers to view and control the victim’s screen.
Ratopak has been distributed via fake Central Bank employment emails in what Symantec calls a narrow, targeted attack aimed at the staff of Russian financial institutions. The attack took place in December, but a similar operation was also spotted in October, researchers said.
In an effort to increase their chances of success, cybercriminals registered a domain (cbr.com.ru) that is similar to the official domain used by Russia’s Central Bank (cbr.ru).
The fake emails contain a link to the attacker’s domain, which is set up to serve an archive file that stores a version of Ratopak signed with stolen certificates. Once it infects a computer, the malware checks for the presence of a virtual machine and ensures that the compromised device’s language is set to Russian or Ukrainian before conducting any malicious activity.
Researchers said many of the infected computers had been running accounting and document management software designed to allow users to securely exchange documents with government organizations for tax purposes.
One piece of software running on many of the infected devices is an accounting application from Russian company SBIS. The firm’s accounting program is referred to as “buh,” a word that means “accountant” in Russian. The attackers have been using URLs that contain this string in an effort to avoid raising suspicion.
“While there is no conclusive evidence of the attacker’s goal, the attacks appear to be financially motivated. The specificity of the targets−employees at certain banks using accounting software to send the government tax information−certainly points towards this goal,” Symantec researchers said in a blog post. “By using Ratopak, which can open a backdoor and log keystrokes, the attackers could position themselves to steal money, either by controlling the compromised computer or using the employees’ stolen login credentials. Any goal beyond that, including what the attackers may have wanted with government tax information, is currently unknown.”
Symantec is not the only security firm to spot attacks launched by this actor. In April 2015, ESET published a report on the activities of the same group, which it had been monitoring since late 2014.
The attacks observed by ESET, whose experts dubbed the malware “Buhtrap,” also targeted the accounting departments of Russian businesses. At the time, the cybercrooks delivered the malware using bogus emails that appeared to carry invoices and service contracts.
Cybercriminals target Russian banks
There are several major cybercrime rings in Russia that specialize in hacking banks. One of the most notorious groups, known as Carbanak and Anunak, reportedly stole $1 billion from 100 banks in Russia and other countries.
The activities of this group, which also targets accounting departments, were exposed by Kaspersky Lab and Fox-IT in February 2015. The cybercrooks took a five-month break after the security firms published their reports, but now they’re back in what Kaspersky calls Carbanak 2.0.
In February, at its 2016 Security Analyst Summit (SAS), Kaspersky Lab detailed the activities of two other groups that hit many Russian banks. One of them, known as Metel and Corkow, infected the targeted organizations’ corporate networks and altered systems so that they could withdraw large amounts of cash from ATMs without actually taking money from accounts.
Another cybercrime ring, dubbed GCMAN, hacked the systems of various banks in an effort to transfer money from the breached companies to various e-currency services. In one case, the attackers deployed a script designed to automatically send $200 to such services every minute.