This Metasploit module allows remote attackers to execute arbitrary code on Exchange Server 2019 CU10 prior to Security Update 3, Exchange Server 2019 CU11 prior to Security Update 2, Exchange Server 2016 CU21 prior to Security Update 3, and Exchange Server 2016 CU22 prior to Security Update 2. Note that authentication is required to exploit this vulnerability. The specific flaw exists due to the fact that the deny list for the ChainedSerializationBinder had a typo whereby an entry was typo’d as System.Security.ClaimsPrincipal instead of the proper value of System.Security.Claims.ClaimsPrincipal. By leveraging this vulnerability, attacks can bypass the ChainedSerializationBinder’s deserialization deny list and execute code as NT AUTHORITYSYSTEM. Tested against Exchange Server 2019 CU11 SU0 on Windows Server 2019, and Exchange Server 2016 CU22 SU0 on Windows Server 2016.Read More