[TUHS] attachments: MIME and uuencode

Paul Winalski paul.winalski at gmail.com
Mon Mar 13 04:33:36 AEST 2017

On 3/12/17, Doug McIlroy <doug at cs.dartmouth.edu> wrote:
> Allowing more or less arbitrary attachments was a real convenience.
> But allowing such stuff to serve as the message proper was
> dubious at best. Not only did it require recipients to obtain
> special software to read some messages; it also posed a
> security threat.
> I still use mailx precisely because it will only display plain text.

Back in the day plain ASCII wasn't really secure, either.  There were
bugs in the firmware of the VT100 and other smartish terminals that
would cause strange behavior if certain malformed control sequences
were received.  For example, causing the bell (actually a loud beep)
to sound continuously until the terminal was power-cycled.  There was
one sequence that stored bad data into the user preferences area of
the EPROM.  That bricked the terminal by causing it to go into a
reset/crash loop.  DEC ended up modifying VMS Mail to filter out ASCII
control characters by default when it displayed email messages.  You
could still display the unfiltered text, but you had to explicitly ask
for that to be done.

-Paul W.

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