Vulnerability Development mailing list archives

Re: SV: Modern hw-killing virus feasible


From: Lynn Crumbling <lynn () X HJSOFT COM>
Date: Thu, 8 Mar 2001 20:12:30 -0500

While I'm sure it's not permanently damaging, it's entirely possible to
alter something, that a reboot can not fix: S registers. Yes, some apps do
fully initialize the modem, setting S register values at program-load. But
most of those only set dialing speed or x3/x4 (detect dial tone). To top
things off, you don't need to be Administrator to write modem
configurations to NVRAM and many modems I've seen have it (obviously
those that don't, aren't at risk). Alas, I don't have an S register list
handy, so there may not even be any that render the modem unusable. But
if I remember correctly, you can do many things with them, including set
CCITT or Bell, adjust dialing speed...

for times = 1 to 20
        $i = random number 0 to 15
        $j = random number 0 to 255
        ats[$i] = $j
next
write current config as default  [at&W1?]
atz [just for kicks]

....would wreak complete havok on the values...

--

- Lynn

Lynn Crumbling, Sr. System Analyst
Analytical Design Solutions, Inc.


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