Microsoft Exchange Vulnerabilities – A Continuing Threat

In recent weeks, hackers have sought to exploit vulnerabilities that Microsoft has identified in its Exchange software that customers have loaded onto their Exchange Servers. These attacks started with a hacking group known as Hafnium and have since affected Microsoft users globally. Microsoft has also detected a new family of ransomware, known as DearCry, being deployed after the initial compromise of Exchange Servers.

To protect against future attacks, Microsoft is advising organizations to identify and update vulnerable on-premises Exchange Servers, and follow its mitigation and investigation advice without delay.

In early March, four Microsoft Exchange security vulnerabilities were identified. The four critical vulnerabilities are a server-side request forgery (CVE-2021-26855) used to authenticate as the Exchange Server, a unified messaging service (CVE-2021-26857) enabling the running of code as SYSTEM and two post-authentication arbitrary file writing