irregular/vulnerable? early usb serial behavior
The librem 5 allows login over a serial usb connection, using a user account on the phone.
However, with repeated connection attempts during early boot it's possible to eventually get into the device before it seems to have properly initialized, and one sees (without doing anything!) what seems to be AT (modem?) commands getting printed into the session, and causing errors:
$ picocom -b 115200 /dev/ttyACM0
picocom v3.1
port is : /dev/ttyACM0
flowcontrol : none
baudrate is : 115200
parity is : none
databits are : 8
stopbits are : 1
escape is : C-a
local echo is : no
noinit is : no
noreset is : no
hangup is : no
nolock is : no
send_cmd is : sz -vv
receive_cmd is : rz -vv -E
imap is :
omap is :
emap is : crcrlf,delbs,
logfile is : none
initstring : none
exit_after is : not set
exit is : no
Type [C-a] [C-h] to see available commands
Terminal ready
PureOS pureos ttyGS0
pureos login: ATPassword:
AT
Login incorrect
ATPasswort: AT
Login incorrect
pureos Login: ATPassword:
Login incorrect
pureos Login:
The device ttyGS0, seems to be a device on the phone.