Ransomware prevalent in cloud-based malware

Cloud-based filesharing, collaboration and social networking applications are ransomware delivery vehicles, according to a report released today

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Cloud-based filesharing, collaboration and social networking applications are common vectors for malware infections, a large portion of of which are ransomware delivery vehicles, according to a report released today.

Javascript exploits and droppers, Microsoft Office macros, and PDF exploits make up 43.7 percent of the total detected cloud malware, said Jamie Barnett, CMO at Netskope, the company that released the report.

"These are typical ransomware delivery vehicles," she said.

Cloud-based applications such as Dropbox can be used to spread malware in a couple of different ways. Attackers can upload the infected files to the cloud service, then share them with victims. Since there are many legitimate users of these services, they are not typically blocked by enterprises.

In addition, if an employee has an infected file that they save in a file-sharing system used throughout a company, the infection can spread to other users.

"At least one out of every 10 enterprises has malware in their cloud storage applications," said Barnett.

Slack made Netskope's top 20 enterprise cloud apps list for the first time since the company began gathering this data in 2014, but it is too early to tell how much malware is coming through this platform.

"We have not been scanning for it yet," Barnett said. "We recently released our Netskope for Slack capability and we haven't yet been scanning for malware in a meaningful way. But we have seen other collaboration apps similar to Slack that have delivered malware."

Slack is a popular new collaboration app that has previously been adopted by individual users and teams, but is now seeing enterprise deployment.

"We're starting to see enterprises standardizing on it and rolling out Slack for their entire organizations," she said.

The average enterprise now has a total of 977 cloud apps, up from 935 last quarter, and 95 percent of them are not enterprise ready.

The worst category was cloud-based marketing applications, where 97 percent of the cloud apps used were not appropriate for the enterprise.

The most secure category was cloud storage, where only 77 percent of cloud apps were not enterprise ready.

According to Netskope, companies are more likely to take the time to do their due diligence before sanctioning a cloud storage application.

As new cloud apps come out, especially new niche applications for specific corporate functions, such as human resources, the total number of cloud applications in an enterprise increases, Barnett said. However, this is offset by enterprises restricting the use of some cloud applications in favor of enterprise-grade alternatives.

Ironically, some kinds of restrictions can actually lead to an increase in the variety of cloud apps that are used.

Say, for example, a company decides to block Dropbox.

"This would often create the opposite of the intended outcome, as it forced people to go and use applications that were far riskier, like Megashare, applications that typically weren't meant for enterprise use," she said.

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