Growing Collaboration Among Criminal Groups Heightens Ransomware Threat for Healthcare Sector

Increased communication and collaboration among cybercrime groups is heightening the ransomware threat for the healthcare sector, according to the Cyber Threat Intelligence League (CTI League), a group that since last March has been functioning as a global volunteer emergency response center for healthcare organizations.

In a report Thursday summarizing its efforts over the past year, the CTI League says it expects ransomware attacks and activities like the trading and selling of databases containing protected health information (PHI) to increase this year. The group also expects an increase in "triple extortion" attacks involving the use of ransomware, data theft, and distributed denial-of-service (DDoS) attacks as leverage to extort money from healthcare entities.

CTI League says it observed increased demand in 2020 for backdoor access to healthcare networks — usually in the form of vulnerable Remote Desktop Protocol (RDP) services — and also an increase in the number of brokers leaking, acquiring, and selling that access. COVID-19-themed lures were and will continue to be a central part of phishing, social engineering scams, and information campaigns that seek to exploit fear and curiosity over the pandemic.

The central role that healthcare services play in fighting the global COVID-19 pandemic — and therefore their perceived increased susceptibility to extortion attempts — will continue to make hospitals and other healthcare services prime targets for cybercriminals in 2021, according to the CTI League report.

Sean O'Connor, leader of the CTI League's Dark team, says healthcare organizations should expect the ransomware landscape in 2021 to mirror last year's landscape in terms of increasing attacks, number of new ransomware groups, and new variants that will surface.

A lot of the activity is being driven by what O'Connor describes as a confluence of events. Among them is the proliferation of dark markets and supply chains offering ransomware-as-a-service that have significantly lowered barriers to entry for cybercriminals. Another major factor is the growing communication and collaboration within the cybercriminal ecosystem on ransomware attacks targeting the healthcare sector.

Rather than just competing with each other, ransomware groups increasingly appear willing to observe and learn from each other and to adapt and apply tactics and extortion methods that have worked for other groups. As one example, O’Connor points to the operators of REvil, one of the most prolific ransomware strains targeting healthcare organizations, openly complimenting and then using the triple extortion tactics used by the operators of DarkSide, another major ransomware threat.

CTI League researchers have also observed collaboration between groups on the use of initial access brokers and money-laundering services — such as Russia's Darknet market Hydra, O'Connor says. Groups have even begun copying each other's ransom notes, and some are picking up where others are leaving off, he says. When the operators of the Maze and Sekhmet ransomware families began tapering off operations, the Egregor family began increasing its victim count, he says. 

"Ransomware is a rapidly evolving threat due to the increased collaboration within the cybercriminal ecosystem," O'Connor notes. 

The CTI League's analysis of ransomware data over the past year identified Maze, Conti, Netwalker, REvil, and Ryuk as the top ransomware variants that impacted healthcare organizations. In total, these ransomware families impacted over 100 healthcare organizations around the world, with over two-thirds of the victims located in North America and Europe.

A CERT of Sorts
The CTI League presently comprises more than 1,500 cybersecurity experts from around the world who are working on a volunteer basis to help healthcare organizations deal with cyberthreats in the midst of the pandemic. It acts like a hub for collecting and disseminating threat and threat actor info to organizations in the sector and others, including law enforcement, government agencies, and telcos. Group members also lend their expertise in threat takedown efforts.

"In one year of the CTI League, we understand how vulnerable and, accordingly, how targeted the healthcare sector is," says Ohad Zaidenberg, founder and executive of CTI League.

Since launching last March, the CTI League has helped multiple healthcare organizations address ransomware threats, he says. As one example, he points to last October when a threat group encrypted computers belonging to 30 healthcare providers, causing severe disruptions in the process. CTI League volunteers used information on the attack released by the Department of Homeland Security's Cybersecurity and Infrastructure Security Agency (CISA) and its own intelligence to identify the adversary’s command-and-control infrastructure to track victims and warn potential targets. A 28-member task force also helped in lawful takedowns of the attacker’s infrastructure.

Zaidenberg compares the work his team is doing to that of a computer emergency response team (CERT) except that it is open to everyone. The goal is to "protect hospitals that can't afford to pay for protection, for hospitals and emergency services that don't know how to do it, and to assist law enforcement organization in their fight for the public safety," he says.