Effective Measures against Spear Phishing Attacks

C.

Among the given options, end-user training would be the BEST protection against spear phishing attacks.

Explanation:

Spear phishing is a type of targeted phishing attack where the attacker sends personalized, fraudulent emails to specific individuals within an organization, pretending to be a trusted source or a known person to trick the recipient into revealing sensitive information, clicking on malicious links, or downloading malware.

While all the given options can provide some level of protection against spear phishing, end-user training would be the most effective because it directly targets the root cause of the problem, i.e., human behavior. The main reason why spear phishing attacks are successful is that they exploit the human element of cybersecurity. People tend to trust emails that appear to come from a known source or contain familiar information, and this can lead them to lower their guard and fall for the attacker's tricks.

By providing regular end-user training on how to identify and avoid phishing attacks, employees can learn how to recognize suspicious emails, understand the different tactics used by attackers, and know how to report any suspected phishing attempts to the appropriate personnel. This can significantly reduce the likelihood of successful spear phishing attacks and help the organization protect sensitive information and systems.

While email content filtering, acceptable use policies, and antivirus software can also help protect against spear phishing, they have limitations. Email content filtering can be bypassed by attackers who use social engineering techniques to craft convincing messages that appear legitimate. Acceptable use policies and antivirus software are important components of a comprehensive security program, but they are not specifically designed to address the human element of cybersecurity that spear phishing exploits.

In conclusion, while all the given options can provide some level of protection, end-user training is the BEST protection against spear phishing attacks as it directly addresses the root cause of the problem, i.e., human behavior, and empowers employees to become an active line of defense against phishing attacks.