1, 2, 3 Owned: New Microsoft Exchange Vulnerabilities

This report details the ProxyShell chained vulnerabilities in Microsoft Exchange (CVE-2021-34473, CVE-2021-34523, CVE-2021-31207) that enable unauthenticated remote code execution and mailbox export-based payload delivery; it documents active exploitation and ransomware deployment (LemonDuck, LockFile), notes large numbers of potentially affected hosts, and provides patching and detection guidance (including an Nmap script) for defenders.