Security in Computing (3rd Edition)

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1 Network Security War Stories CS 161/194-1 Anthony D. Joseph September 7, 2005 September 7, 2005 CS161 Fal 2005 Joseph/Tygar/Vazirani/Wagner 2 About Me • Joined faculty in 1998 – MIT SB, MS, PhD • Contact info – adj @ cs.berkeley.edu – http://www.cs.berkeley.edu/~adj/ • Research Areas: – Mobile/wireless computing, network security, and security testbeds • Office hours: 675 Soda Hall, M/Tu 1-2pm September 7, 2005 CS161 Fal 2005 Joseph/Tygar/Vazirani/Wagner 3 Outline • War stories from the Telecom industry • War stories from the Internet: Worms and Viruses • Crackers: from prestige to profit • Lessons to be learned September 7, 2005 CS161 Fal 2005 Joseph/Tygar/Vazirani/Wagner 4 Phone System Hackers: Phreaks • Earliest phone hackers? • 1870’s teenagers • 1920’s (first automated switchboards) • Mid-1950’s saw deployment of automated direct-dial long distance switches September 7, 2005 CS161 Fal 2005 Joseph/Tygar/Vazirani/Wagner 5 US Telephone System (mid 1950’s) A dials B’s number Exchange collects digits, assigns inter-office trunk, and transfers digits using Single or Multi Frequency signaling Inter-office switch routes call to local exchange Local exchange rings B’s phone September 7, 2005 CS161 Fal 2005 Joseph/Tygar/Vazirani/Wagner 6 Early 1970’s Phreaks • John Draper (AKA “Captain Crunch”) – Makes free long-distance calls by blowing a “precise” tone (2600Hz) into a telephone using a whistle from a cereal box… – Tone indicates caller has hung up L stops billing! – Then, whistle digits one-by-one • “2600” magazine help phreaks make free long-distance calls • But, not all systems use SF for dialing…
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2 September 7, 2005 CS161 Fal 2005 Joseph/Tygar/Vazirani/Wagner 7 Blue Boxes: Free Long Distance Calls • Once trunk thinks call is over, use a “blue box” to dial desired number – Emits MF signaling tones • Builders included members of California's Homebrew Computer Club: – Steve Jobs (AKA Berkeley Blue) – Steve Wozniak (AKA Oak Toebark) • Red boxes, white boxes, pink boxes, … – Variants for pay phones, incoming calls, … September 7, 2005 CS161 Fal 2005 Joseph/Tygar/Vazirani/Wagner 8 The Game is On • Cat and mouse game between telcos and phreaks – Telcos can’t add filters to every phone switch – Telcos monitor maintenance logs for “idle” trunks – Phreaks switch to emulating coin drop in pay phones – Telcos add auto-mute function – Phreaks place operator assisted calls (disables mute) – Telcos add tone filters to handset mics – … • The Phone System’s Fatal Flaw? – In-band signaling! – Information channel used for both voice and signaling – Knowing “secret” protocol = you control the system September 7, 2005 CS161 Fal 2005 Joseph/Tygar/Vazirani/Wagner 9 Signaling System #7 • “Ma Bell” deployed Signaling System #6 in late 1970’s and SS#7 in 1980’s – Uses Common Channel Signaling (CCS) to transmit
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This note was uploaded on 01/29/2008 for the course CS 194 taught by Professor Joseph during the Fall '05 term at University of California, Berkeley.

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Network security intro - Phone System Hackers: Phreaks...

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