A large number of Microsoft Exchange email servers in Europe, the United States, and Asia are currently vulnerable to remote code execution flaws due to their public internet exposure. These servers are running out-of-date software that is no longer supported, and as a result, they do not receive any updates or security patches. As a result, they are vulnerable to a variety of security issues, some of which have critical severity ratings.
Recent internet scans conducted by The ShadowServer Foundation have disclosed that nearly 20,000 Microsoft Exchange servers are presently accessible via the public internet and have reached the end of life stage. These statistics, however, may not be indicative of the whole picture. Yutaka Sejiyama, a Macnica security researcher, carried out additional research and identified over 30,000 Microsoft Exchange servers that have reached end-of-life status.
Sejiyama’s Shodan scans discovered nearly 30,635 unsupported Microsoft Exchange devices on the public web. There were 275 Exchange Server 2007 instances, 4,062 Exchange Server 2010 instances, and a whopping 26,298 Exchange Server 2013 instances.