https://www.cnbc.com/2018/12/20/microsoft-ie-emergency-patch-issued.html

Criminals are currently exploiting a newly found flaw in several popular versions of Microsoft's Internet Explorer browser, according to the company, security researchers at Google and the Department of Homeland Security.

Attackers can use the vulnerability to gain broad access to computer systems, according to the U.S. Computer Emergency Response Team (CERT). The flaw works by driving users to an infected website via a fraudulent "phishing" email, according to the CERT. Once there, you unknowingly download malware that grants the attacker rights to any system you are able to access, according to Microsoft.