To download Oracle Audit Vault and Database Firewall, go to the Software Delivery Cloud, select 'Oracle Database' from the 'Product Pack' drop-down menu, and choose 'Linux x86-64' as your platform, the click on the 'Go' button.

Note that you also need the iso image of Oracle Linux 5 Update 8 64 bit: Go to edelivery.oracle.com/linux, select 'Oracle Linux' from the drop-down menu and choose 'x86 64 bits' and select 'Oracle Linux 5 Update 8 64 bit' to download.