Over 10 different threat groups exploit Microsoft mail server flaws, researchers say Updated: Updated: March 11, 2021 17:00 IST The anti-virus software maker said threat actors potentially used Microsoft’s mail server flaws to install malware like web shells and gain backdoor entry into victims’ email servers. It has identified the presence of web shells on more than 5,000 unique servers in over 115 countries. Share Article Over 10 different threat groups exploit Microsoft mail server flaws. | Photo Credit: Reuters The anti-virus software maker said threat actors potentially used Microsoft’s mail server flaws to install malware like web shells and gain backdoor entry into victims’ email servers. It has identified the presence of web shells on more than 5,000 unique servers in over 115 countries.