2 ms·

Oh, it's entirely possible in principle (I don't know about the details of T1 in this specific case). Many years ago, there used to be a vulnerability with a l

Oh, it's entirely possible in principle (I don't know about the details of T1 in this specific case). Many years ago, there used to be a vulnerability with a lot of modems where you could send a ping packet to a machine connected via dialup, and the machine would send back a response that its modem would interpret as telling it to hang up the call: https://seclists.org/bugtraq/1998/Sep/192 https://seclists.org/bugtraq/1998/Sep/192 The OSI model is an abstraction that can be broken by implementation bugs or design flaws, not an immutable law of the universe. EDIT: I see that some of the Twitter replies beat me to mentioning this.

myself248 2y ago
Hayes figured out how to make that impossible: The "guard time" interval. When you want to interact with the modem, you have to send _nothing_, not a single character, for a whole second before sending +++ and then another whole second of nothing. Only then would the modem place you into command mode. That way, +++ could happily appear in payload but never mess with the modem, because there'd be other payload either side of it. Of course they patented this, and anyone who licensed the patent was likewise immune, but the manufacturers who didn't, could easily be plonked like this. My first "hack" involved a BBS scripting language that involved a delay command... ;)