While the WannaCry ransomware that compromised Britain’s NHS hospitals has gotten lots of attention lately, Proofpoint researchers identified a new kind of ransomware that may cost its victims more. The criminals behind the NHS attack were asking for a $300 payment, but this new Jaff ransomware is demanding $3,300 — more than 10 times as much.

Sailing With Necurs

Jaff ransomware uses the same spam methods that were effective for Dridex and Locky. The use of the Necurs botnet to deliver the poisoned spam email is a signature trait of this long-standing criminal group, so it is no surprise that Jaff uses the Necurs ship to sail on the network seas.

SecurityWeek noted that Necurs had been quiet for the first three months of 2017, and it only recently returned to activity when it started redistributing Locky.

Jaff follows the group’s previous distribution of Dridex and Locky into the ransomware arena. But there are a few notable changes in Jaff, which suggested that the actors tweaked the underlying code, perhaps hoping to gain evasive maneuverability against hash-based identification programs.

Researchers have yet to determine how the release of this new ransomware will affect the distribution of the older Locky variant. But the existence of multiple changes proves the malware authors are always seeking to improve or change their own code and, ultimately, the ransomware itself.

Poisoned PDF at the Center of Jaff Ransomware

Both Locky and Jaff infect victims through a similar malicious PDF attachment delivered by Necurs. When opened, the PDF executes a Word document that contains malicious macros. Social engineering is used to convince the end user to open the PDF.

The same actors previously released the Necurs-delivered Bart ransomware, which was a variant of Locky, SecurityWeek claimed. That malware did not require an active command-and-control (C&C) server to encrypt a victim’s files.

These actors are willing to try anything that might add to their coffers. Because cybercriminals are so vigilant in their schemes, users must be trained to identify suspicious-looking documents and act as the first line of defense when it comes to ransomware.