What is email (electronic mail)?

Business email compromise (BEC). A BEC is an exploit in which the attacker gains access to a corporate email account and spoofs the owner's identity to defraud the company or its employees, customers or partners of money. In some cases, an attacker simply creates an account with an email address that's similar to one on the corporate network. A BEC is also referred to as a man-in-the-email scam.

Ransomware. Ransomware is a subset of malware in which the data on a victim's computer is locked, typically by encryption, and payment is demanded before the ransomed data is decrypted and access is returned to the victim. The motive for ransomware attacks is nearly always monetary, and unlike other types of attacks, the victim is usually notified that an exploit has occurred and is given instructions for how to recover from the attack. Payment is often demanded in a virtual currency -- such as bitcoin -- so that the cybercriminal's identity isn't known.

Email security
Email is designed to be an open and accessible platform that enables users to communicate with each other and with people or groups within an organization. As a result, it isn't inherently secure, and email security is vital. Email security describes the various techniques that individuals, organizations and service providers can use to protect sensitive information kept in email communications and accounts from unauthorized access, loss or destruction.
Organizations should implement the following best practices to ensure proper email security:
Password rotations. Individuals can proactively protect their accounts by creating strong passwords and changing them frequently.
Spam filters. Users should also create spam filters and folders to separate potentially malicious emails and junk mail, as well as install and run antivirus and antimalware software on their computers. Service providers should install firewalls and spam-filtering software apps to protect users from unrecognized, malicious or untrustworthy messages.