Security firm F-Secure says there has been a spike in web shells being detected following the release of proof-of-concept attack code for the ProxyLogon flaw. The flaw is one of four zero-day flaws patched by Microsoft in early March. Microsoft has released a patch for the flaw, but half of in-use on-premises Exchange servers remain unpatched. Security experts warn that patching alone does not guarantee server security because attackers could have breached networks before any updates were installed.”]
Source: https://www.bankinfosecurity.com/ms-exchange-flaw-causes-spike-in-trdownloader-gen-trojans-a-16236