Ransomware attacks against individual endpoints are so passé. According to reports out this week from two security research teams, financially motivated cybercriminals are updating their ransomware playbooks in search of bigger payoffs from their victims. Increasingly, they're making more money by putting bigger game in the crosshairs, namely networked business assets such as file shares, servers, network hosts, and infrastructure-as-a-service cloud infrastructure.

A new study from researchers at Vectra shows that the biggest threat to enterprises from ransomware today is malicious encryption of shared network files. Whereas ransomware attacks against isolated endpoints should be no big deal to recover from with any modicum of backup procedures, ransomware targeting of file shares is much more likely to trigger "all-hands-on-deck" emergencies. First of all, attackers are able to do a lot more damage with minimal action by taking advantage of the scale of share volume availability to numerous local systems. It takes only a single access point to lock access to documents across numerous departments or divisions at a targeted organization.

"In a volume-sharing system, a single infected host could encrypt an entire networked volume, resulting in a global impact on the target organization's business and systems," the report explains.

What's more, in many instances, these shared volumes are themselves used as a part of backup procedures for other systems so recovery can become quite tricky without offline backups.

"The files must be recovered from the most recent cold backup if the ransom is not paid," the report says. "Backup systems attached to a network are also at risk, which is why cold offline backups are critical for recovery."

The potential risk — and payout for extortionary criminals — increases tremendously when ransomware attackers can successfully target cloud provider infrastructure and storage shares. The Vectra report points to several high-profile attacks against cloud hosting firms DataResolution.net and iNSYNQ as examples of the dynamic at play.

"The fallout from ransomware attacks against cloud service providers is far more devastating when the business systems of every cloud-hosted customer are encrypted," says Chris Morales, head of security analytics at Vectra. "Today's targeted ransomware attacks are an efficient, premeditated criminal threat with a rapid close and no middleman."

According to Vectra's study, the volume of these attacks is on the decline, but that could simply be a factor of criminals getting more discriminating and more effective with ransomware targeting. There are plenty of new and effective ransomware techniques and malware families deluging enterprises with these network-centric attacks. For example, in the past month, there have been two waves of attacks specifically targeted against enterprise storage devices from QNAP Network and Iomega.

And just this Monday, the industry saw more evidence of the evolution of the ransomware strain MegaCortex, which targets important files on servers and network hosts and is tied to attacks that have asked for as much as $5.8 million from large organizations. New analysis out from researchers with Accenture iDefense shows a version 2 of MegaCortex floating around that shifts this from a very manual ransomware tool to something with automated self-execution features.

"The authors of MegaCortex v2 have redesigned the ransomware to self-execute and removed the password requirement for installation. The changes suggest that the malware authors traded some security for ease of use and automation," writes Leo Fernandes, senior manager for malware analysis and countermeasures at Accenture iDefense. "Potentially, there could be an increase in the number of MegaCortex incidents if actors decide to start delivering it through email campaigns or dropped as a secondary stage by other malware families.

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