Single-hop and Multi-hop MANET Security

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Single-hop and Multi-hop MANET Security

• S. Srinivasan
• Professor of CIS
• University of Louisville
• Louisville, Kentucky, USA

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Outline

• Mobile Ad hoc Network (MANET)
• Single-hop Networks
• Multi-hop Networks
• Current models
• Denial of Service (DoS)
• Selfish node
• Routing
• Our research
• Open research areas involving MANET

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MANET

• MANET is a temporary network
• No central server
• Infrastructure-free
• Comparison with wired network
• Trust establishment

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MANET Diagram
Wireless network
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MANET Security

• Principal aspects are
• Confidentiality
• Integrity
• Vulnerabilities are
• Malicious nodes
• Covert channels
• Eavesdroppers

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Single-hop Networks

• Base Station (BS) plays a critical role
• BS is involved in communication with every Mobile
  Node (MN)
• BS takes care of channel assignment for RTS
  (Request To Send) and CTS (Clear To Send) packets
• Usual MAC protocol is slotted ALOHA (GSM uses
  this for access requests)

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Single-hop Networks
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Single-hop Networks

• Usually 7 frequencies are reused
• Neighboring cells use different frequencies
• Within each cell dedicated single channels are
  used for each direction of traffic

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Multi-hop Networks

• Extends coverage area of single-hop networks
• Mobile node to mobile node connections allowed
• More demands placed on MAC protocols than
  single-hop networks
• Multi-hop networks can provide connection-oriented
  service by partitioning available bandwidth to
  multiple channels

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Multi-hop Networks
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Multi-hop Networks
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Multi-hop Networks

• Common protocols used are the Floor Acquisition
  Multiple Access (FAMA) class of protocols
• 802.11 DCF (Distributed Coordination Function)
  protocol is very cost effective and mature. This
  is actually a CSMA/CA.
• Typically the transmission range of a mobile
  device is not a constraint but the traffic a cell
  can support is

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Multi-hop Networks

• Policy of not reusing a channel in adjacent cells
  works in single-hop networks
• In multi-hop networks, sharing of data and
  control channel in the entire service area is
  preferable
• Benefits of multi-hop networks over single-hop
  networks are
• robustness
• higher bandwidth availability
• spatial reuse

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Multi-hop Networks

• Robustness comes from not having a single path
  such as via an Access Point (AP)
• Example email
• Bandwidth is higher at shorter range
• Less power is required to transmit over shorter
  distances
• Since multiple paths exist to the network over
  multiple nodes, there is no bottleneck of an AP

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Current Models

• Denial of Service (DoS)
• Malicious nodes and selfish nodes cause DoS
• Yi et al (2002) discuss Mobile Certification
  Authority (MOCA) protocol for MANETs using PKI
• MOCA distributes Certificate Authority
  functionality to selected nodes based on trust

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Current Models

• Avoine et al (2002) discuss their fair key
  exchange model called Guardian Angel
• Uses probabilistic techniques without any trusted
  third party for key exchange

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Current Models

• Selfish nodes
• Buttyan et al (2003) show using simulation how
  selfish nodes fail to participate in packet
  forwarding
• Buttyan study shows that every node spends 80 of
  energy for packet forwarding
• A nuglet counter is used here to keep track of
  selfish node behavior. It is a tamper resistant
  hardware security module attached to a node.
  Detects selfishness in packet forwarding.

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Current Models

• Nuglet counter is decreased when it originates a
  packet and increased when it forwards a packet
• Nodes that participate in the ad hoc network must
  maintain a positive nuglet counter
• If n is the number of intermediate nodes to the
  destination, then the originator can send the
  packet if its nuglet counter is gt n. In that
  case the nuglet counter is decreased by n.
  Otherwise, the node cannot send its packet
• When the node forwards one packet for others then
  its nuglet counter is increased by one

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Current Models

• Michiardi et al (2002) have developed the CORE
  (Collaborative Reputation) model for monitoring
  behavior of neighboring nodes for selfish
  behavior
• Each node monitors the behavior of neighboring
  nodes for a specific function. If performance
  matches expected behavior then observation is
  positive.
• One node sends a probing message to a node one
  hop away. If the message is acknowledged within
  the timeout period then the neighbor did the
  forwarding.
• Lack of positive values would result in node
  getting isolated

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Current Models

• How selfish behavior is detected
• Each node selects a backoff value in the range
  0, CW where CW is contention window
  duration
• When channel is idle, the backoff counter is
  decremented by one after every time slot
• Counter is frozen when channel is busy
• Misbehaving nodes attempt to choose a backoff
  value in the range 0, CW/4 thereby they get
  quicker access to the bus
• This is controlled by the receiver monitoring the
  sender behavior by assigning a backoff value to
  sender

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Current Models

• Routing
• Main methods are
• AODV (Ad hoc On-demand Distance Vector)
• DSDV (Destination Sequenced Distance Vector)
• AODV is a reactive protocol
• DSDV is a proactive protocol
• DSDV maintains a dynamic routing table at all
  times

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Current Models

• Yang et al, ACM conf., 2002, have developed a
  unified method called Self Organized Security
  (SOS) scheme using AODV method
• SOS does not assume any prior trust arrangement
  among nodes
• Each node in the network needs a token to
  participate
• Tokens have expiration time stamp
• Well-behaving nodes gain longer time duration
  before renewal

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Taxonomy
Author Main Focus Research method Contribution Software Results
Yi Secure routing simulation Secure Aware routing metric, Secure routing protocol ns2 Secure AODV, secure route discovery
Avoine Fair key exchange analytical Probabilistic fair exchange protocol without third parties Cryptographic key exchange without trusted third parties
Buttyan Node cooperation in packet forwarding simulation Packet forwarding C Tamper resistant security module, robust packet forwarding
Michiardi Selfishness in MANET nodes simulation Detect selfish behavior through collaboration ns2 Lack of packet forwarding
Yang Routing and packet forwarding simulation Proactively isolate malicious nodes ns2 Prevents DOS attacks in network layer
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Our Research

• We are pursuing four different research threads
• Development of Threshold Index (TI) using fuzzy
  logic
• X xi is a sample space of significant
  parameters (e.g., packets lost, number of
  collisions)
• A (xi, µj(xi)), xi e X where µj is the
  grade of membership of xi

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Our Research

• m
• S wj yj
• j 1
• TI ---------------------------
• m
• S wj
• j 1
• where yj denotes the output value (weight)
  associated with the particular rule in the fuzzy
  set. Weight wj is min(µj(NC), µj(PL))

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Our Research

• Rule strength wj min(µj (xi)) where
• i e 1, 2, , n and n is the number of input
  metrics for each rule
• Given k membership values, m kn
• A sample fuzzy relation is shown next
• In the example, we use the weights to be 1, 5 or
  9 based on the firing rule corresponding to
  small, medium or large

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Fuzzy Relation
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Example
Rule(j) µj(NC) µj(PL) Wt. (yj) RuleStrength(wj) wjyj
1 0 0 1 0 0
2 0 0 1 0 0
3 0 0.5 5 0 0
4 0 0 1 0 0
5 0 0 5 0 0
6 0 0.5 9 0 0
7 1 0 5 0 0
8 1 0 9 0 0
9 1 0.5 9 0.5 4.5
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Our Research

• TI is used to classify the threat faced by mobile
  nodes.
• Classifications used are normal, uncertain and
  vulnerable
• Extensive simulation using ns2 software has been
  done
• Currently we are in the process of testing the
  scenarios using specialized hardware

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Our Research

• A second thread of research involving MANETs
  deals with multi-hop networks as opposed to
  single-hop networks
• Multi-hop networks involve not only laptops but
  also PDAs and cell phones
• Trust aspects play a key role identifying nodes
  for inclusion in the network

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Our Research

• One work is based on a general security control
  for a multi-hop network
• This is aimed at preventing attacks on paging and
  registration, also forging Foreign Agent (FA)
• Uses mobile IP security (provides continuous
  connectivity for mobile hosts)
• One protection method is to require all MNs to
  register
• Authenticate MN, FA, HA as a unit
• Allow only authenticated nodes to be in the
  multi-hop route

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Our Research

• Another work is based on secured
  macro/micro-mobility protocol for multi-hop
  cellular IP
• Macro-mobility refers to support between local
  domains for mobility of MNs
• Micro-mobility refers to support within a local
  domain for mobility of MNs
• Multi-hop paging cache is used to maintain
  location of MNs
• Multi-hop routing cache is used to maintain
  multi-hop routes

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Multi-hop Heterogeneous Network
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Simulation Result
P denotes a prime number indicating the number of
bits used for encryption in the elliptic curve
cryptosystem
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Our Research

• A third line of research involves mobility
  management
• Mobility management involves knowing what nodes
  are allowable in a network at a given time
• A fourth thread of research involves traceback of
  nodes. This will help in identifying malicious
  nodes.

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Open Research areas in MANET

• MOCA method could be extended to browsing
  neighboring nodes routing tables. Goal is to
  find multiple routes. This will help in avoiding
  flooding attacks.
• CORE method does not address attacks from active
  intruders. Nuglet counter could be better
  utilized for mutual provision of information
  services
• Guardian Angel method could be extended to
  include DoS or routing attacks

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Open Research areas in Multi-hop Networks

• Studies are available based on routing or
  selfish-node behavior that involve AODV (Ad hoc
  On demand Distance Vector) or DSDV (Destination
  Sequenced Distance Vector). A hybrid approach is
  a viable alternative for performance
  considerations.
• In Multi-hop cellular networks, we could find
  ways to improve the MAC protocols for faster
  throughput

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References

• Michiardi, P., and Molva, R., CORE A
  COllaborative REputation mechanism to enforce
  node cooperation in Mobile Ad Hoc Networks,
  Communication and Multimedia Security Conference,
  2002.
• Buttyán, L., and Hubaux, J., Stimulating
  Cooperation in Self-Organizing Mobile Ad Hoc
  Networks, Mobile Networks (MONET), 2003.
• Avoine, G. and Vaudenay, S., Cryptography with
  Guardian Angels Bringing  Civilization to 
  Pirates Report on a Working Session on Security
  in Wireless Ad Hoc  Networks, Levente Buttyan and
  Jean-Pierre Hubaux (eds.), ACM Mobile Computing
  and  Communications Review (MC2R), Vol. 6., No.
  4., 2002.
• Michiardi, P., Molva, R. Prevention of Denial of
  Service Attacks and selfishness in Mobile Ad Hoc
  Networks, Research Report RR-02-063 - January
  2002.

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References

• Ermanno Pietrosemoli, Mesh Networks
  http//wireless.ictp.trieste.it/school_2004/lectur
  es/ermanno/mesh.pdf
• Yi, S., Naldurg, P., Kravets, R., A
  Security-Aware Ad Hoc Routing Protocol for
  Wireless Networks, 6th World Multi-Conference on
  Systemics, Cybernetics and Informatics (SCI
  2002), 2002.
• S. Alampalayam, A. Kumar, S. Srinivasan, Mobile
  Ad hoc Network Security A Taxonomy, 7th IEEE
  Intl Conf. on Computer Communications Security,
  Phoenix Park, South Korea, Feb. 23-25, 2005.
• Yang, H., Meng, X., and Lu, S., Self-Organized
  Network Layer Security in Mobile Ad Hoc
  Networks, ACM MOBICOM Wireless Security Workshop
  (WiSe'02), Atlanta, 2002.

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References

• Y.D. Lin and Y.C. Hsu, Multihop Cellular A new
  architecture for wireless communications, IEEE
  InfoCom 2000, 1273-1282.
• R. Ananthapadmanabha, B. S. Manoj, and C. Siva
  Ram Murthy, Multi-hop Cellular Networks The
  architecture and routing protocols, 12th Intl
  Conf. on PIMRC, vol.2, Sept. 2001, G-78-G82.
• B. Xie, A. Kumar, S. Srinivasan, GSCP A General
  Security Control Protocol for Heterogeneous
  Multi-hop Network
• B. Xie, A. Kumar, S. Srinivasan, Secured
  Macro/Micro-Mobility Protocol for Multi-hop
  Cellular IP
• C. J. Fullmer and J. J. Garcia-Luna-Aceves,
  Floor Acquisition Multiple Access (FAMA) for
  Packet Radio Networks, ACM SIGCOMM 1995.