North American Network Operators Group

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remember the lesson of the sendsys bomb

  • From: Paul A Vixie
  • Date: Sat Jan 01 02:22:32 2000

at the 1988 usenix in san francisco, rick adams of uunet ran the uucp bof and
told a story of a forged sendsys message intended to melt somebody's inbox.
this was timed to coincide with a usenix, since most news admins would be at
the show rather than home watching their servers.  (shows did not have terminal
rooms at that time.)  thus the cats were away the mice were at play.

(sendsys, for those of you not in the news field, is a 'control message' that
used to be used to get a news-neighbor to send their "sys" file via e-mail;
this was used for debugging and early access controls on it were nonexistent.)

well, most of the news servers by that time were configured to mail all such
control messages to their local administrator, who could then approve them by
hand if they weren't stupid and abusive (which they almost always were).  so
the forger's intent of inundating some victim's inbox with thousands of "sys"
files from autoresponding systems seemed destined for some frustration.

except that so many admins were away and had set up "vacation" autoresponders
saying "hi, i'm at usenix, i'll be back on friday" and so few of these vacation
robots had enough intelligence to not autorespond to other robotic e-mail such
as "sendsys message received - approval required" that the news system ended
up melting the victim's inbox ANYWAY.

the lesson of the sendsys is that after a 24 or 36 hour period of continuous
wakefulness, sean and alan and the rest are going to have to SLEEP.  *that*
will be the time when some perfectly normal event like a route spew or heavy
flap or genetic IOS defect will make itself known, and *that* will be the time
when Y2K finally kicks us all in the head.  not because of the date change,
but because everybody stayed awake too long and upset their normal vigilence.