VMware vSphere Data Protection (VDP) 5.1, 5.5 before 5.5.9, and 5.8 before 5.8.1 and the proxy client in EMC Avamar Data Store (ADS) and Avamar Virtual Edition (AVE) 6.x and 7.0.x do not properly verify X.509 certificates from vCenter Server SSL servers, which allows man-in-the-middle attackers to spoof servers, and bypass intended backup and restore access restrictions, via a crafted certificate.