Backdoor.Yonsole has two variants (A and B) and follows in the footsteps of another retro piece of malware attacking the Master Boot Record area on hard-disk drives: the Zimuse worm. The most dangerous feature of the malware is the fact that it can overwrite the hard-drives Master Boot. area with 512 bytes of code, thus preventing the system from booting up. The BitDefender antivirus has also been updated with signatures to block and delete both versions.”]

