Dridex malware has been used in the past to steal financial information from users in a sophisticated manner. But Buguroo security researchers found that the malware itself was vulnerable to attacks, and this revelation led to more information about how dangerous it actually is.

How the Vulnerability Works

Dridex has been developed by the cybercrime group Evil Corp. The Trojan launches when a poisonous Office macro attached to a spam email gets clicked. Usually purporting to be an invoice, the malware spam then uses local DNS poisoning to launch a redirection attack.

This kind of attack employs replica sites that substitute for the intended destination, which are then used to collect personal and banking information. Since the user never touches the intended destination, that legitimate site will not know an attack has occurred.

Analyzing the JavaScript code responsible for stealing banking credentials allowed the researchers to determine the URL of a command-and-control (C&C) panel that was used by the malware’s operators. That represented a treasure trove of information for researchers.

“Using this information, in addition to the information obtained from our JavaScript analysis and searching the Intel Big Data from Buguroo Labs, we noticed some coincidences between this panel and others we already had detected in the past,” Buguroo said in its report.

“Looking deeply into the panel responses, we found that this panel version was vulnerable, and we were able to recover part of the compromised information.”

What Research Shows About Dridex

The recovered information included account numbers, names, last login dates, credit card numbers, card types and information on the issuing bank and country of origin. SecurityWeek noted that European and English-speaking countries were still the main targets, but they also found credit cards related to African and Latin American companies.

The researchers also estimated that the global cost of Dridex was around $20 million after just a 10-week period, assuming 1 out of 10 stolen credit cards can be used by the attackers and considering the $500 average of stolen money per account.

Buguroo further concluded that the Dridex malware is being used by different cybercriminal groups — not necessarily the developers of the first Dridex versions. It came to this conclusion because of the “exceedingly rare vulnerability of a C&C server to a basic attack,” which implies the current operators are not as sophisticated as the original developers.

This could mean that the Dridex mechanism was sold on the black market to others. These other cybercriminals may not be as technologically adept as the originators, hence the C&C vulnerability.

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