Protecting your Privacy with FreeBSD and Tor Christian Brffer - - PowerPoint PPT Presentation

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Protecting your Privacy with FreeBSD and Tor Christian Brffer - - PowerPoint PPT Presentation

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Protecting your Privacy with FreeBSD and Tor Christian Brffer brueffer@FreeBSD.org MeetBSD Warsaw, Poland November 18, 2007 Overview Who needs anonymity anyway? Anonymization concepts T or FreeBSD What else to take

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SLIDE 1

Protecting your Privacy with FreeBSD and Tor

Christian Brüffer

brueffer@FreeBSD.org

MeetBSD – Warsaw, Poland

November 18, 2007

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SLIDE 2

MeetBSD 2007 2

Overview

  • Who needs anonymity anyway?
  • Anonymization concepts
  • T
  • r
  • FreeBSD
  • What else to take care of?
  • Demonstration
  • Summary
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SLIDE 3

MeetBSD 2007 3

Overview

  • Who needs anonymity anyway?
  • Anonymization concepts
  • T
  • r
  • FreeBSD
  • What else to take of?
  • Demonstration
  • Summary
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SLIDE 4

MeetBSD 2007 4

Who needs anonymity anyway?

  • Journalists
  • Informants, whistleblowers
  • Dissidents (China, Myanmar...)
  • Socially sensitive information (abuse, AIDS)
  • Law enforcement (anonymous crime

reporting, tips, surveillance...)

  • Companies (research competition...)
  • Military (covert operations...)
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SLIDE 5

MeetBSD 2007 5

Who needs anonymity anyway?

  • You?

– EU data retention directive

  • connection data gets stored for 6 – 24 months
  • phone, SMS, IP, e-mail, dial-in data
  • (finally we'll be safe from all those terrorists!)

– which interests do you have? – who do you talk to?

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SLIDE 6

MeetBSD 2007 6

Who needs anonymity anyway?

  • Criminals

– already do illegal stuff – no problem doing more illegal stuff to get

anonymity

  • identity theft
  • renting bot-nets
  • creating bot-nets
  • cracking one of the thousands of insecure

computers in the net

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SLIDE 7

MeetBSD 2007 7

Who needs anonymity anyway?

  • Very different groups
  • All with the same goal

anonymity needs diversity

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SLIDE 8

MeetBSD 2007 8

Overview

  • Who needs anonymity anyway?
  • Anonymization concepts
  • T
  • r
  • FreeBSD
  • What else to take care of?
  • Demonstration
  • Summary
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SLIDE 9

MeetBSD 2007 9

Anonymization concepts

  • Proxy

(Source: http://www.at-mix.de )

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SLIDE 10

MeetBSD 2007 10

Anonymization concepts

  • Proxy

– fast – simple – single point of failure

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SLIDE 11

MeetBSD 2007 11

Anonymization concepts

  • Mix

(Source: http://www.tm.uka.de/itm )

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SLIDE 12

MeetBSD 2007 12

Anonymization concepts

  • Mix cascade

(Source: http://sarwiki.informatik.hu-berlin.de )

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SLIDE 13

MeetBSD 2007 13

Anonymization concepts

  • MIX cascade

– slow

  • public key encryption
  • mixing

– distributed trust – one MIX secure

connection anonymous

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SLIDE 14

MeetBSD 2007 14

Overview

  • Who needs anonymity anyway?
  • Anonymization concepts
  • Tor
  • FreeBSD
  • What else to take care of?
  • Demonstration
  • Summary
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SLIDE 15

MeetBSD 2007 15

T

  • r
  • The Onion Router
  • Open source, BSD license
  • TCP-overlay network
  • Provides SOCKS interface
  • Available on many platforms:

– Windows, Linux, MacOS X – FreeBSD, OpenBSD, NetBSD – Solaris, other UNIX systems

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SLIDE 16

MeetBSD 2007 16

T

  • r
  • Aims to combine positive attributes of

proxies and mixes

– speed (fast)

  • session keys
  • TCP multiplexing

– distributed trust

  • Design goals: deployability, usability,

flexibility, simplicity

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SLIDE 17

MeetBSD 2007 17

T

  • r

(Source: http://www.torproject.org )

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SLIDE 18

MeetBSD 2007 18

T

  • r

(Source: http://www.torproject.org )

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SLIDE 19

MeetBSD 2007 19

T

  • r

(Source: http://www.torproject.org )

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SLIDE 20

MeetBSD 2007 20

T

  • r
  • Exit policies (for nodes)

– control which TCP connections can exit your

node

– default policy blocks SMTP, NNTP and some

  • thers

– allows the rest (HTTP, SSH...) – reject everything: middleman- or entry-node

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SLIDE 21

MeetBSD 2007 21

T

  • r
  • Hidden Services

– Services with no published IP address – Cannot be physically found – Can be provided anywhere connection to T

  • r

network is possible

– Resist Denial of Service – Resist censorship – Addresses: duskgytldkxiuqc6.onion

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MeetBSD 2007 22

T

  • r

(Source: http://www.torproject.org )

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SLIDE 23

MeetBSD 2007 23

T

  • r

(Source: http://www.torproject.org )

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SLIDE 24

MeetBSD 2007 24

T

  • r
  • Legal issues

– may be forbidden in some countries – crypto restrictions (Great Britain, “RIPA”) – special laws (Germany, “hacker paragraph”) – destination servers have Exit-Node IP in their

logs

  • node operator has to answer if there is trouble
  • server may get ceized (happened before)
  • ...
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SLIDE 25

MeetBSD 2007 25

Overview

  • Who needs anonymity anyway?
  • Anonymization concepts
  • T
  • r
  • FreeBSD
  • What else to take care of?
  • Demonstration
  • Summary
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SLIDE 26

MeetBSD 2007 26

FreeBSD

  • Well suited for T
  • r (node) operation
  • Operational security

– Jails (jail(8)) – Disk/swap encryption (geli(8), gbde(4)) – audit(4) – mac(4) framework

  • Hardware crypto(4) acceleration
  • Well maintained T
  • r-related ports
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SLIDE 27

MeetBSD 2007 27

FreeBSD

  • Important ports

– security/tor – security/tor-devel – www/privoxy – net-mgmt/vidalia – security/trans-proxy-tor

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SLIDE 28

MeetBSD 2007 28

Overview

  • Who needs anonymity anyway?
  • Anonymization concepts
  • T
  • r
  • FreeBSD
  • What else to take care of?
  • Demonstration
  • Summary
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SLIDE 29

MeetBSD 2007 29

What else to take care of?

  • Name resolution

– Some applications bypass configured proxy

(hi Firefox < version 1.5!)

  • Cookies, web-bugs, referrer

– Disable cookies/referrer or better use Privoxy

  • Connection Exit-Node <-> Destination

– Not encrypted! Use secure protocols

  • Services that require registration

– T

  • r cannot help you there
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SLIDE 30

MeetBSD 2007 30

Overview

  • Who needs anonymity anyway?
  • Anonymization concepts
  • T
  • r
  • FreeBSD
  • What else to take care of?
  • Demonstration
  • Summary
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SLIDE 31

MeetBSD 2007 31

Overview

  • Who needs anonymity anyway?
  • Anonymization concepts
  • T
  • r
  • FreeBSD
  • What else to take care of?
  • Demonstration
  • Summary
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SLIDE 32

MeetBSD 2007 32

Summary

  • T
  • r useful for stealthy net usage
  • Can be used to provide resilient services
  • FreeBSD a very good choice as a platform

All this very much needed in light of recent laws etc T

  • r website: http://www.torproject.org
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SLIDE 33

MeetBSD 2007 33

Questions?

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SLIDE 34

MeetBSD 2007 34

Thank you for your attention!