The number of new ransomware samples more than doubled in the first quarter of this year, a new study by McAfee Labs shows. New ransomware increased by 118%, while the most prevalent strains were Dharma (aka Crysis), GandCrab and Ryuk.

McAfee detected 504 threats per minute in the first three months of 2019, while criminals uploaded over 2.2 billion stolen account credentials on the dark web. The most common attack vector was malware, followed by account hijacking. New malware samples rose by 35%, but those targeting Mac OS actually decreased by 33%. Other notable trends are the rise of targeted campaigns and of fileless attacks.

Read more: New ransomware grows 118% as cybercriminals adopt fresh tactics and code innovations