Wireless Sensor Networks: Security issues, implications and future directions

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Wireless Sensor Networks Security issues,
implications and future directions

• Chetan Nanjunda
• Wireless Systems Security - Project

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Background Sensor devices

• small hardware devices
• 8-16 bit, 4-8MHZ CPU
• sense the surrounding environment
• light, sound, movement, chemicals..
• perform some computation
• supported by a small OS
• relay information
• 8-15Kbps

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Background Sensor networks

• A collection of sensor devices spanning a
  geographical area
• Stationary sensor networks
• Sensors do not move after deployment
• Mobile Adhoc sensor networks
• Sensors are expected to move around

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Applications Issues

• Military sensor networks
• to detect and gain as much information as
  possible about enemy movements, explosions, and
  other phenomena of interest.
• Wireless traffic sensor networks
• Wireless surveillance sensor networks
• for providing security in shopping malls, parking
  garages, and other facilities.
• Wireless parking lot sensor networks
• to determine which spots are occupied and which
  are free.

• Self configurable
• Scalable
• Limited battery power
• Ability to be easily deployed
• Cost
• Size
• Reliability

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Military Sensor networks Security Analysis -
Assets

• Tactical advantage
• Sensor sensing ability
• Self configuration
• Sensor processing ability
• Scalability
• Protocols, security procedures
• Small size
• Response time to event
• Accuracy of information
• Authenticity of sensor network
• Authenticity of information
• Tiny OS
• Node, link reliability

• Sensor device, hardware
• Sensor network connectivity
• Battery power
• Communication bandwidth
• Command Node
• Services offered by application
• Information
• Location of sensors, cmd node
• Encryption Information (like key)
• Personnel using sensor network
• Sensor communication ability
• All Soldiers lives
• Vehicles, aircraft, weapons and artillery

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Security Analysis Perpetrators

• Enemy- jammers, bombs, direction finders, intel
• Traitor- sensor designer, deployer or a traitor
  sensor
• Nature
• Virus writer
• Foreign government
• Other wireless network operators
• Users bombs, vehicles (running over the
  sensors)
• Thieves
• Black market
• Press
• Hackers
• Terrorist
• Sensor protocol designers (disgruntled employees)

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Security Analysis - Threats

• Jamming
• Sensor destruction due to- bombs, vehicles/people
  running over, nature
• Node, link failure
• False information
• Unanticipated attack from enemy
• Sensor failure because of battery drain out
• Delay in important information
• Network failure
• Sensor down because of virus/ other attack
• Loss of valuable information
• Battery drain because of unnecessary flooding of
  packets
• Information (tactical) leak to adversary (enemy)
• Enemy attacks the min cut of the network to
  break the network
• Zeroing out of encryption keys during battery
  replacement
• Traitor sensor acting as command center
• Jammer jamming the command center

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Security Analysis Existing Safe Guards

• Encryption
• Power aware routing
• Connectionless network
• Self configuring deployment techniques
  configuration mode, operational mode
• Antijam- DSSS
• Authentication codes sensor node, data and
  route
• Using large number of dispersed sensors
• Event driven OS to conserve power
• Redundant command centers
• A group of sensors acting as command centers
  increases reliability
• Conservative routing algorithms (minimum spanning
  trees) to reduce flooding and conserve batteries
• Hard casing the sensors to protect them against
  bombs
• Periodic network reliability check operations

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Security Analysis - Vulnerabilities

• Low bandwidth- congestion problem
• Single even creates a lot of redundant data in a
  small location more collisions
• No virus protection/ Firewall
• Exploding batteries
• Link/node failures cause information loss
• Operating environment heat, sand, rain, bombs
• Command center (if exists) is a single point of
  failure
• In spanning tree based routing a single link
  failure results in network failure

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Security Analysis - Additional Controls

• Advanced batteries technology
• Better processing power in sensors
• Use of redundant links to increase network
  reliability
• Antivirus software/firewall
• Adaptive communication range (power control)
• Random backoff mechanisms to reduce collisions
• Power aware protocols coordination between
  protocols at different layers
• Power aware encryption/authentication

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Major security issues

• Security issues with routing
• minimum cost spanning tree
• single link failure partitions the network
• connection less
• calculating new routes is expensive
• Security issues with scheduling
• single event generates multiple simultaneous
  responses
• increases probability of collisions
• adversary with dummy events can choke the
  network, generate false alarms

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Some potential solutions

• incorporate multiple disjoint paths
• improve the reliability
• additional packets
• random back off before transmitting
• reduces probability of collisions
• increases delay
• time division based technique
• avoids collisions
• time slot assignment difficult
• requires synchronization

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Future directions for military sensor networks

• evolving battery technologies
• cost and size of sensors going down
• expect the sensor networks to grow dense
• higher bandwidth and capacity
• defense communities (e.g. DARPA, NIST) working on
  it.

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Questions ?
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• Thank You!!