Russia-linked hackers have exploited several flaws in the Exim mail transfer agent (MTA) Hundreds of thousands of servers are still unpatched. The U.S. National Security Agency (NSA) has issued an advisory on the vulnerability. NSA recommends patching Exim servers immediately by installing version 4.93 or newer. In May, RiskIQ experts identified more than 900,000 vulnerable servers in May. Experts noticed that many servers were updated in May, but there are still thousands of vulnerable servers.”]
Source: https://securityaffairs.co/wordpress/104209/hacking/russia-apt-exim-flaws.html