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Anonymity in MANETs Threats and Mitigations

Roy Friedman, Neer RoggelTechnion, Israel Institute of Technology

Computer Science Department{roy,nroggel}@cs.technion.ac.il

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Outline

• What are MANETs?

• Anonymity scenarios

• Attackers and threats

• Our approach: IP hopping

• Limitations and future work

• Open discussion

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What is a MANET?

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5

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What are MANETs?

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What are MANETs?

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Anonymity Scenarios

• Battlefield– Units in motion– Sensor network

• Content sharing– Oppressive regime– Rights protected content

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Attacker Capabilities

• Eavesdropping• Geolocating a node• Device fingerprinting• Generating traffic• Man in the middle• Node compromise• Worm holes

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Threats to Anonymity

• Irrefutably implicating a node• Distorting route construction• “Chattering laptops”• Attacks on timing• Traffic analysis

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Traffic Analysis

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Traffic Analysis Example

A B M D E

K

P

O

L

AB

D

EK

O

P

L

IP1IP2

IP3

IP4IP5

IP7

IP8

IP6

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Our Approach

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Simple Example

A

BM

D

E

K

PO

L

( ) ( )iX K KIP E X E i

IP1IP2

IP3

IP4IP5

IP7

IP8

IP6

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IP Hopping

• Step 1: agree on shared information

A B M D E

Axg A Bx xg A B Mx x xg A B M Dx x x xg

E D M B A

Exg E Dx xg E D Mx x xg E D M Bx x x xg

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IP Hopping

• Step 2: derive temporary addresses

A B M D E E D M B Ax x x x x x x x x xg K g

(2 )iA KIP E i (2 1)i

E KIP E i

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IP Hopping

• Step 3: use temporary addresses

A

B

M

D

E

[Ai,B,M,D,Ei]

[Ai,B,M,D,Ei]

[Ai,B,M,D,Ei]

[Ai,B,M,D,Ei]

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Traffic Analysis Revisited

A B M D E

K

P

O

L

IP1IP2

IP3

IP4IP5

IP7

IP8

IP6

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Limitations

• Routing efficiency– Discovery, maintenance

• In-band agreement

• Network services– Authentication, service discovery, address

binding, address assignment

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Future Research Directions

• More IP information leaks

• Better routing mechanisms

• TCP stream information leaks

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Discussion

• How can we tell the network to help us find someone we are looking for without telling the network who it is we are looking for?

• Once the route is known, how do we ensure that all nodes along the way are capable of receiving the packet and forwarding it?