QNAP NAS devices are being targeted in attacks by the AgeLocker ransomware, which encrypts the device’s data, and in some cases, steal files from the victim. Ransomware is ransomware that utilizes an encryption algorithm called Age (Actually Good Encryption) designed to replace GPG for encrypting files, backups, and streams. When the ransomware encrypts files, it will leave behind a ransom note named HOW_TO_RESTORE_FILES.txt that tells the victim that their device was specifically targeted in the attack.
Source: https://www.bleepingcomputer.com/news/security/agelocker-ransomware-targets-qnap-nas-devices-steals-data/