Incorrect access control mechanisms in Citrix Receiver Desktop Lock 4.5 allow an attacker to bypass the authentication requirement by leveraging physical access to a VDI for temporary disconnection of a LAN cable. NOTE: as of 20161208, the vendor could not reproduce the issue, stating "the researcher was unable to provide us with information that would allow us to confirm the behaviour and, despite extensive investigation on test deployments of supported products, we were unable to reproduce the behaviour as he described. The researcher has also, despite additional requests for information, ceased to respond to us."