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| Phrack Seventeen |
| 07 April 1988 |
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| File 9 of 12 : Data-Tapping Made Easy |
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| --FEATURE ARTICLES AND REVIEWS- |
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| TAPPING COMPUTER DATA IS EASY, AND CLEARER THAN PHONE CALLS ! |
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| BY RIC BLACKMON, SYSOP OF A FED BBS |
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| Aquired by Elric of Imrryr & Lunatic Labs UnLtd |
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| Note from Elric: This file was written by the sysop of a board for computer |
| security people (run on a CoCo), as far as I know the board no longer exists, |
| it was being crashed by hackers too much... (hehe). |
| --------------------- |
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|
| FOR SEVERAL YEARS, I ACCEPTED CERTAIN BITS OF MISINFORMATION AS |
| TECHNICALLY ACCURATE, AND DIDN'T PROPERLY PURSUE THE MATTER. SEVERAL FOOLS |
| GAVE ME FOOLISH INFORMATION, SUCH AS: A TAP INTERRUPTS COMPUTER DATA |
| TRANSMISSIONS; DATA COULD BE PICKED UP AS RF EMANATIONS BUT IT WAS A MASS OF |
| UNINTELLIGIBLE SIGNAL CAUSED BY DATA MOVING BETWEEN REGISTERS; ONE HAD TO BE |
| IN 'SYNC' WITH ANY SENDING COMPUTER; DATA COULDN'T BE READ UNLESS YOU HAD A |
| DIRECT MATCH IN SPEED, PARITY & BIT PATTERN; AND ONLY A COMPUTER OF THE SAME |
| MAKE AND MODEL COULD READ THE SENDING COMPUTER. THIS IS ALL PLAIN SWILL. IT |
| IS IN FACT, AN EASIER CHORE TO TAP A COMPUTER THAN A TELEPHONE. THE TECHNIQUE |
| AND THE EQUIPMENT IS ALMOST THE SAME, BUT THE COMPUTER LINE WILL BE MORE |
| ACCURATE (THE TWO COMPUTERS INVOLVED, HAVE ERROR CORRECTING PROCEDURES) AND |
| CLEARER (DIGITAL TRANSMISSIONS HAVE MORE DISTINCT SIGNALS THAN ANALOG |
| TRANSMISSIONS). |
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| FIRST, RECOGNIZE THAT NEARLY ALL DATA TRANSMISSIONS ARE SENT IN CLEARTEXT |
| ASCII SIGNALS. THE LINES CARRYING OTHER BIT-GROUPS OR ENCIPHERED TEXTS ARE |
| RARE. SECOND, THE SIGNAL APPEARS ON GREEN AND RED (WIRES) OF THE PHONE LINE |
| ('TIP' AND 'RING'). THE DATA IS MOST LIKELY ASYNCHRONOUS SERIAL DATA MOVING |
| AT 300 BAUD. NOW THAT 1200 BAUD IS BECOMING MORE CHIC, YOU CAN EXPECT TO FIND |
| A GROWING USE OF THE FASTER TRANSMISSION RATE. FINALLY, YOU DON'T NEED TO |
| WORRY ABOUT THE PROTOCOL OR EVEN THE BAUD RATE (SPEED) UNTIL AFTER A TAPED |
| COPY OF A TRANSMISSION IS OBTAINED. |
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| IN A SIMPLE EXPERIMENT, A TAPED COPY OF A DATA TRANSMISSION WAS MADE |
| WITH THE CHEAPEST OF TAPE RECORDERS, TAPPING THE GREEN AND RED LINES BEYOND |
| THE MODEM. THE RECORDING WAS THEN PLAYED INTO A MODEM AS THOUGH IT WERE AN |
| ORIGINAL TRANSMISSION. AT THAT POINT, HAD IT BEEN NECESSARY, THE PROTOCOL |
| SETTINGS ON RECEIVING TERMINAL COULD HAVE BEEN CHANGED TO MATCH THE TAPE. NO |
| ADJUSTMENTS WERE NECESSARY AND A NICE, CLEAR ERROR-FREE DOCUMENT WAS RECEIVED |
| ON THE ILLICIT VIDEO SCREEN AND A NEAT HARD-COPY OF THE DOCUMENT CAME OFF THE |
| PRINTER. THE MESSAGE WAS INDEED CAPTURED, BUT HAD IT BEEN AN INTERCEPTION |
| INSTEAD OF A SIMPLE MONITORING, IT COULD HAVE BEEN ALTERED WITH A SIMPLE WORD |
| PROCESSOR PROGRAM, TO SUIT ANY PURPOSE, AND PLACED BACK ON THE WIRE. |
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| WERE I TO HAVE AN INTEREST IN INFORMATION ORIGINATING FROM A |
| PARTICULAR COMPANY, AGENCY, OR OFFICE, I THINK THAT I WOULD FIND IT FAR MORE |
| PRODUCTIVE TO TAP A DATA TRANSMISSION THAN TO TAP A VOICE TRANSMISSION, AND |
| EVEN MORE REWARDING THAN GETTING HARDCOPY DOCUMENTS. |
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| *SIGNIFICANT & IMPORTANT INFORMATION IS MORE CONCENTRATED IN A DATA |
| TRANSMISSION. |
| *SIGNIFICANT & IMPORTANT INFORMATION IS MORE EASILY LOCATED IN DATA |
| TRANSMISSIONS THAN IN MASSES OF FILES OR PHONE CALLS. |
| *TRANSMITTED DATA IS PRESUMED TRUE, AND WHEN ALTERATION IS DISCOVERED, |
| IT'S READILY BLAMED ON THE EQUIPMENT. |
| *THE LAWS CONCERNING TAPS ON UNCLASSIFIED AND NON-FINANCIAL COMPUTER |
| DATA ARE EITHER QUITE LACKING OR ABJECTLY STUPID. |
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| THE POINT OF ALL THIS IS THAT THE PRUDENT MANAGER REALLY OUGHT TO ENCRYPT ALL |
| DATA TRANSMISSIONS. ENCRYPTION PACKAGES ARE CHEAP (A 'DES' PROGRAM IS NOW |
| PRICED AT $30) AND ARE EASY TO USE. |
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| ------------------------------- |
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