From zdnet.com
Email is incredibly useful, which is why we all still use it. But chief among its downsides (along with getting caught in a group-cc’d message hell) is that email remains one of the most common routes for hackers to attack businesses.
Around one in every hundred messages sent is a malicious hacking attempt. That might not seem like a large figure, but when millions of messages are sent every day, it adds up — especially when it just takes one employee to fall victim to a phishing message and potentially lead to a whole organisation being compromised.
For example, the cyber attack against the Democratic National Committee that led to thousands of private emails being exposed in the run up to the US Presidential election started with just one successful phishing email, while countless espionage and malware campaigns have also gained entry to organisations via an email-based attack.