managed services expert continuously monitoring and maintaining your server, then it can easily leave you vulnerable to a data breach or malware infection. One of the largest compromises of on-premises assets happened between January and March of 2021 and is still causing problems for thousands of businesses around the world. Microsoft Exchange Server, which is the largest on-premises email solution, was the target of a major hack that began being detected in early January 2021. It took until March 2021 for Microsoft to develop and issue patches for the four vulnerabilities that were exploited during the hack. Up to now, it’s estimated that 250,000 organizations around the world, 30,000 of those in the U.S., have been impacted. Many of them are SMBs. Microsoft Exchange Server has approximately 78% of the on-premises email market share. Attacks were first perpetrated by a known state-sponsored Chinese hacking group called Hafnium. Once news of the vulnerabilities got out, soon many other cybercriminals were joining in and attacking as many Exchange Servers as possible before patches could be issued. When the four found vulnerabilities are used together, they allow a hacker to elevate themselves to administrative privileges on a server, write a file to any path, and run code. So, they can basically take over the Exchange Server. Victims that have their Exchange Server hacked can suffer:
Stolen email data
Use of their company domain for spam and phishing
Ransomware infection and ransom demand
Compromised usernames and passwords
Use of the server for nefarious activities
The planting of a “back door” that allows a hacker to remain in the system even after Microsoft’s patches have been applied.
Which Microsoft Email Solutions Were Impacted? If you use Microsoft 365 and Exchange Online, then you were not impacted by this breach. It only affected the on-premises email software in Microsoft Exchange Server. The impacted versions are:
Exchange Server 2010
Exchange Server 2013
Exchange Server 2016
Exchange Server 2019