Qlocker is a ransomware malware. Malware in this category makes data inaccessible (mainly by encrypting it) and demands a ransom to regain access. In the case of Qlocker, it affects victims' files by storing them in password-protected 7zip archives. The original extensions of the compromised files are replaced with the ".7z" extension. Qlocker tends to target exclusively QNAP-branded network-attached storage (NAS) devices. Once the data is locked, the ransomware drops ransom notes - "!!!READ_ME.txt" - in the affected folders.