Taiwan-based network-attached storage maker QNAP warned customers on Thursday to secure their devices against attacks pushing DeadBolt ransomware payloads.

“According to the investigation by the QNAP Product Security Incident Response Team, the attack targeted NAS devices using QTS 4.3.6 and QTS 4.4.1, and the affected models were mainly TS-x51 series and TS-x53 series,” the NAS maker said.

In April, QNAP also urged NAS users to disable Universal Plug and Play port forwarding on their routers to prevent exposing them to attacks from the Internet.

With QNAP devices also being targeted by other ransomware families such as Qlocker and eCh0raix, all owners should immediately take the above measures to secure their data from future attacks.

First spotted in attacks targeting QNAP NAS devices in late January, DeadBolt ransomware hijacks the QNAP device’s login page to display a screen stating, “WARNING: Your files have been locked by DeadBolt.”

DeadBolt ransomware returned in February in another campaign targeting ASUSTOR NAS devices and allegedly using a zero-day vulnerability.