Recent research shows that cyber-attackers are exploiting recently discovered severe vulnerabilities in Microsoft Exchange servers, tracked as ProxyLogon. According to CheckPoint Research, defenders are now in a race with malicious actors to thwart attacks against unpatched on-premise Microsoft Exchange servers with the US the country most affected, seeing 17% of all exploit attempts, followed by Germany, the UK, the Netherlands and Russia.
Microsoft’s initial reports suggested that the Chinese APT group named Hafnium was exploiting ProxyLogon. The ProxyLogon vulnerabilities enable attackers to read emails from a physical, on-premise Exchange server without authentication – Office 365 and cloud instances are not affected – and by chaining additional vulnerabilities, can take over their victim’s mail server, posing a critical security risk.
The rapid adoption of this new exploitation method by several APTs indicates that a large number of threat actors are eagerly waiting to leverage the critical vulnerabilities in popular products. Go patch your Microsoft Exchange servers before it’s late. Further, experts recommend removing web shells, changing credentials, and looking for malicious activity in case of potential infections.