It was found that D-BUS message bus service / messaging facility did not update the byte-order flag of the message properly by swapping the byte order of incoming messages into their native endiannes. A local, authenticated user could use this flaw to send a specially-crafted message to a system service (like Avahi or NetworkManager), using the system bus, potentially leading to disconnect of such a service from system bus (denial of service).

References: [1] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=629938 [2] https://bugs.freedesktop.org/showbug.cgi?id=38120

Upstream patches: [3] http://cgit.freedesktop.org/dbus/dbus/commit/?h=dbus-1.2&id=6519a1f77c61d753d4c97efd6e15630eb275336e (in upstream v1.2.28 version)

[4] http://cgit.freedesktop.org/dbus/dbus/commit/?h=dbus-1.4&id=c3223ba6c401ba81df1305851312a47c485e6cd7 (in upstream v1.4.12 version)

The dbus-daemon in D-Bus 1.2.x through 1.4.x, 1.6.x before 1.6.20, and 1.8.x before 1.8.4, sends an AccessDenied error to the service instead of a client when the client is prohibited from accessing the service, which allows local users to cause a denial of service (initialization failure and exit) or possibly conduct a side-channel attack via a D-Bus message to an inactive service.