Some Thoughts on "Garbage Picking"

Garbage picking is the art of finding things that someone else has thrown away.

Hackers on time-sharing systems are long familiar with the technique of asking the operating system for some memory or mass storage space that has not yet been zeroed out, and then dumping out whatever was in there to the screen or printer.  Things like password files and system programs are always updated or backed up from lime to time, and that's when a "garbage copy" will be created.  The alert hacker will find this if he or she looks hard enough.

You can even do some garbage picking with your own microcomputer!  Occasionally, when a software house creates a disk, it copies over an entire disk, not just the programs that they happen to be selling on that disk.  You might find old copies of the vendor's programs sitting in there, or all kinds of other stuff.

For those of you without computers, there are other ways you can join in on the fun.  Many a tale has been told on the local bulletin boards about the enterprising phone phreaks who snuck around to their local phone company's central office early one morning and snooped through the Dumpsters.  In the old mechanical switching areas, you might find wires, relays, and other bits and pieces that an electronics hobbyist would enjoy.  In areas served by electronic switching, computer printouts are more likely, and you might even find the garbage hoppers locked to prevent pholks like you from snooping around.  Remember,

other people's garbage is sometimes considered their private property.  Be sure to check with your local authorities on the legalities of digging into large corporations' back yards before you find out what the rules are the hard way.  One person who almost got into trouble over this was a New York City sculptor who was poking through the trash cans around Richard Nixon's townhouse and got picked up by the SS (Secret Service).  He told the judge that he was planning to make a sculpture of the former president out of garbage, and he wanted to use the real stuff.  The judge, obviously, a man of refined artistical tastes, allowed the sculptor to poke through the garbage without molestation.

Other kinds of garbage' picking require some more technical knowledge and a bit of construction ability.  One possibility that could keep you project builders busy is a crosstalk amplifier.  For those of you who aren't familiar with the term, crosstalk (on your telephone) is when you hear another conversation usually very faintly) underneath a phone conversation that you're having.  If you build an amplifier that can filter out the background noise and amplify only the narrow bandwidth where the voice is transmitted through the phone lines, you might be able to make out what the folks are saying, for all the good it will do you.

But there are other things you can hear in this electronic garbage heap.  Suppose one day you hear crosstalk of a modem conversation? If you could amplify it and feed it into your computer, you would be able to monitor someone else's entire computer session.  Suppose you hear someone entering in Touch-Tone codes to some local call extender?  All you have to do is build yourself a tone decoder (you can find schematics for these things in any RadioShack) and figure out what the person entered.  Obviously, once you are able to amplify the crosstalk to a reasonable level, your best bet is to tape-record the material so that you can experiment with the best way to feed it into the computer or tone decoder that will be further deciphering it.

There have been tales told of one enterprising phreak who built a tone decoder and then called up his favorite call extender.  He then called some "dead" line (such as the silent half of a loop line somewhere; other possibilities could be a disconnected number [you hear silence after the recording finishes] or even your own phone, if you have a second line you can use) and turned on his tape recorder.  It wasn't too long before he heard the crosstalk of someone else using the extender, and he picked up ten new codes inside of a week!

Of course, he needed a working code to sign onto the thing in the first place, but there are some extenders where you can "hold the line open" by hitting some key every now and then.  The nice thing about this kind of hacking is that you only need to make one phone call to find things out, while standard hacking requires a separate phone call for each attempt at a new code.  No system in existence could detect a fellow with a tape recorder and a tone decoder listening in, although it's certainly possible that someday, someone could design their phone circuits to be 100% free of crosstalk.

That's all we have for now on the subject of garbage picking.  If you come up with any more places where an inquisitive person might find some interesting information lying around, be sure to write in and let us know.  Please include your method of "digging up" the garbage, and suggestions to all those other people out there who will try to duplicate your results.