What are screen locker trojans and how do they differ from ransomware?

Screen locker trojans are a specific type of malicious software that blocks a user's full access to the operating system or specific device functions, but does not encrypt the actual files on the hard drive. Unlike classic ransomware, which mathematically transforms documents, photographs, and databases using cryptographic algorithms, lockers typically create a graphical interface over all windows demanding a ransom. They often mimic official messages from law enforcement or government agencies, claiming alleged legal violations and blocking the desktop, task manager, and key combinations.

Technically, the implementation of lockers is simpler than creating advanced ransomware. Attackers can use legitimate screen locking mechanisms or modify registry keys responsible for launching the operating system shell, such as the explorer.exe file. Due to the absence of a complex encryption process, access recovery in most cases happens much faster and easier. If the user's files remain untouched, removing the lock does not require finding a unique decryptor or paying money to the attackers, making this type of threat less destructive to data.

To combat screen locker trojans, standard methods of emergency system recovery are used. The main way to clean an infected PC is booting into safe mode with command prompt support or using external bootable drives with antivirus rescue tools. After booting, specialists check system startup, look for suspicious executable files, and restore modified system registry keys. Regular backups of system configurations and the use of reliable protection tools with behavioral analysis are also effective prevention measures.