This talk presents the current knowledge on Direct Memory Access attacks aiming to unlock a user logon session. The Input Output Memory Management Unit (IOMMU) functioning and its integration within the main operating systems (Windows, macOS and Linux) is firstly addressed. Then, the existing DMA attacks using an external peripheral on a switched on computer are explained with a particular focus on IOMMU bypassing on macOS until 10.12.4 version. These attacks give an access to a valid logon session even if the computer is locked. This research was performed in order to prepare the upcoming french RAPID project by Synacktiv: DMArvest.
 Only Intel VT-d technology will be discussed in this document