TELECOM Digest OnLine - Sorted: Re: MIT's 5ESS: (was: NN0 Central Office Codes)

Re: MIT's 5ESS: (was: NN0 Central Office Codes)

Garrett Wollman (
Fri, 11 Nov 2005 23:38:46 UTC

In article <>, Joe Morris
<> wrote:

> Thread drift question: how common are successful hacking (old
> definition of the word "hack") attempts against MIT's 5ESS?

I've never heard of one, although that doesn't necessarily mean
anything, since I don't know the people who manage it. According to
the first hit on Google, it's located in E19, with extensions in 24
and NW12 (i.e., the usual places for network gear). I have no idea
where in E19 it is, or how well-secured those locations are -- but
phone blocks are exposed in a whole bunch of locations that are
probably easier to access. There's also the additional challenge that
many lines, particularly "class A" lines with unlimited access, are
ISDN lines using the AT&T proprietary BRI signalling to communicate
with 7506 desk phones. But telephone equipment is ancient history;
who would want to mess with that when there are *computers* around?!

One story I can tell, as it was relayed to me by a hacker who was
there: the original 7506es had a firmware bug. When the handset was
off-hook, the built-in clock stopped running (presumably because they
were using the same timer interrupt for the call timer). LCS was an
early adopter of the ISDN phones, and my colleague told me that AT&T
sent a technician to every office in the building to extract a ROM
from each phone and replace it with a fixed version. They tried to
get one of the buggy ROMs to hack on; I don't recall if they were
successful. (This would have been mid-1980s.)

> I'm having trouble imagining today's MIT students being able to resist
> the challenge of hacking into the switch and making it do
> "interesting" things.

But don't forget that hacking ethics would prevent them from doing
anything so interesting as to have an impact on public safety.

Garrett A. Wollman | As the Constitution endures, persons in every | generation can invoke its principles in their own
Opinions not those | search for greater freedom.
of MIT or CSAIL. | - A. Kennedy, Lawrence v. Texas, 539 U.S. 558 (2003)

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