Public proof-of-concept (PoC) exploits for ProxyLogon could be fanning a feeding frenzy of attacks even as patching makes progress. Microsoft has issued a one-click mitigation tool in light of the ongoing swells of attacks. The number of attacks against Microsoft Exchange Servers has increased tenfold in the wake of the disclosure of the proxyLogon group of security bugs. The most-attacked country has been the United States (accounted for 17 percent), followed by Germany (6 percent) and Russia (5 percent)
Source: https://threatpost.com/microsoft-exchange-cyberattacks-one-click-fix/164817/