# D-Bus D-Bus is a well-known **IPC** (Inter-Process Communication) protocol (and daemon) that helps applications to talk to each other. The use of D-Bus is great because it allows to implement discovery and signaling. The D-Bus session is by default addressed by environment variable `DBUS_SESSION_BUS_ADDRESS`. Using **systemd** variable `DBUS_SESSION_BUS_ADDRESS` is automatically set for user sessions. D-Bus usage is linked to permissions. D-Bus has already had several [security issues](https://www.cvedetails.com/vulnerability-list/vendor_id-13442/D-bus-Project.html) (mostly **DoS** issues), to allow applications to keep talking to each other. It is important to protect against this type of attack to keep the system more stable. Domain | Object | Recommendations --------------- | -------------- | ------------------------------------ Platform-DBus-1 | Security model | Use D-Bus as IPC. Platform-DBus-2 | Security model | Apply D-BUS security patches: [D-Bus CVE](https://www.cvedetails.com/vulnerability-list/vendor_id-13442/D-bus-Project.html)