Ransomware attackers in the past year have begun to launch small, targeted campaigns, seeking a better return on their investment of time and money.
Cybercriminals are expanding beyond ransomware "spray and pray" attacks delivered by spam, and focusing instead on specific industries, geographies, or companies of a particular size with ransomware phishing campaigns, according to security experts.
"For most of 2016, ransomware campaigns were sent by spam. On some days, tens of millions of emails were sent out," says Patrick Wheeler, director of threat intelligence for Proofpoint. He says spray and pray campaigns were designed to infect as many machines as possible with the expectation that a certain percentage of the victims would pay the ransom.
Ransomware will mostly involve targeted campaigns in the future because attackers know they can get more money with this method, says Anton Ivanov, lead malware analyst with Kaspersky Lab. Attackers behind ransomware campaigns have gone as far as creating special teams with specific developer skills to penetrate networks and language skills to write phishing emails that appear more convincing, too, he says.
Financial organizations, higher-education institutions, and healthcare, manufacturing, and technology companies, are some of the industries that have been hit this year with targeted ransomware campaigns.
"We find when ransomware targets specific verticals, it is usually healthcare and higher education. We don't know why these verticals, but maybe because there is a large user base," says Wheeler.
A previously undocumented strain of the Defray ransomware was used in one attack against healthcare companies and educational institutions, while another Defray attack targeted manufacturing and technology companies, according to a Proofpoint report.
PetrWrap, a Petya-based ransomware variant, targeted financial organizations across the globe, according to Kaspersky.
Wheeler says the Philadelphia ransomware authors initially targeted healthcare companies, while Petya's authors concentrated on regions within Germany during the spring. Other ransomware campaigns also targeted specific geographies: Serpent's authors focused their campaign on the Netherlands then Belgium, while Crysis targeted German organizations, he says.
Company size also factors into targeted ransomware attacks. Mamba ransomware authors target large organizations with more than 1,000 endpoints, Ivanov says, citing the high-profile attack against the San Francisco Municipal Transportation Agency as one example.
"They are focusing on big organizations because with ransomware, [the payout] is based on how many endpoints you can compromise," Ivanov says, adding that Mamba is still active and targeting organizations in the Middle East.
Meantime, while the Philadelphia and Petya authors started out with targeted campaigns, their strategy eventually shifted. "Once ransomware goes global, it is not used as a targeted campaign. That's what happened with Philadelphia and Petya," Wheeler says.
Philadelphia targeted healthcare companies before it later become a commodity and was sold as a ransomware-as-a-service (RaaS), a situation similar to Petya, which initially targeted companies in Germany, explains Wheeler.
Defending against targeted or spray-and-pray ransomware attacks is similar: each require backing up data frequently, dedicating a team to analyze the organization's endpoint security and activity, and ensuring all control processes are in place on the network, Ivanov says.
"Targeted ransomware attacks will continue to evolve," Ivanov warns, so companies need to take steps to reduce the impact.
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