Reply to post: Re: So easy to fix...

Dongle bingle makes two MEELLION cars open to exploit

Anonymous Coward
Anonymous Coward

Re: So easy to fix...

CAN is a broadcast bus (think of it as a distributed memory region). Only one node is permitted to "write" to a location by sending a message with a particular identifier value (unless you get in to the use of more complex higher-level protocols), but any node is permitted to "read" it be receiving messages with that identifier.

All nodes participating in (active) bus communications transmit, even if it's just to say "received" or "that message was not valid when it got here". However, a device like this (assuming it's directly connected to the CAN bus, which is not always the case if it does via the OBDU connector) does not (and should not) send acknowledge bits, error frames or anything else as it is not part of the design and it's failure modes have not been considered.

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