of course they cant protect you from all of the exploits/ransomwares.
its what they have said in their product information :
Protection
Complete Data Protection
Absolute power in the most efficient antivirus available today. Bitdefender Total Security 2018 works against all threats – from viruses, worms and Trojans, to ransomware, zero-day exploits, rootkits and spyware. Your data and your privacy are in good hands.