Researchers have spotted a malvertising campaign that is delivering two payloads to victims: the Vidar information stealer and GandCrab ransomware.

Near the end of 2018, Malwarebytes Labs began tracking a malvertising campaign delivering a variety of payloads. Researchers analyzed the infection chain and traced it to the Fallout exploit kit. They observed this package downloading what they thought was the Arkei stealer, but a closer look revealed the malware to be Vidar, a customizable stealer of passwords, credit card details and digital wallet credentials.

At that point, Malwarebytes analysts looked into Vidar’s command-and-control (C&C) server, discovering that the attacks were retrieving GandCrab ransomware from that location. This sequence of events enables threat actors to first steal victims’ personal and financial information before extorting them for the return of their encrypted data.

A Busy Few Months for the Fallout Exploit Kit

The Fallout exploit kit has been busy over the past few months. In September 2018, FireEye observed the exploit kit targeting users in Japan, Korea, the Middle East, Southern Europe and other countries in the Asia-Pacific region. In that campaign, Fallout infected victims with GandCrab ransomware.

This package of exploits didn’t waste time in diversifying its payloads. Researchers at McAfee observed Fallout exposing users to Kraken ransomware in October 2018. That same month, Palo Alto Networks detected a campaign in which the exploit kit delivered Azorult malware, another threat capable of stealing important information.

How to Block GandCrab and Other Malvertising Payloads

As it continues to evolve, the Fallout exploit kit will likely begin delivering even more payloads. Security professionals should therefore help protect their organizations by consistently leveraging the four steps of vulnerability assessment to keep software up-to-date. Organizations should also help defend against ransomware like GandCrab by using an endpoint management solution to monitor their IT assets for suspicious activity.