Add CVE-2021-28480/28481 (vKEV)

[daffainfo]

PR Information

Microsoft Exchange Server Remote Code Execution Vulnerability (ProxyNotFound)

Template validation

• Validated with a host running a vulnerable version and/or configuration (True Positive)
• Validated with a host running a patched version and/or configuration (avoid False Positive)

[Akokonunes]

Hi @daffainfo

Thanks for the submission ! After reviewing, ProxyNotFound differs from ProxyLogon  the ProxyRequestHandler validates that Host == BackEndServer.Fqdn before proxying, making reliable remote detection without knowing the server's internal FQDN unfeasible. Due to this limitation, we've decided not to accept this as a bounty. We appreciate your effort!

Thanks again