Denial of Service in Sensor
Networks
Szymon Olesiak
Outline
Denial of Service (DoS)- description
 Underwater Sensor Networks (UWSN) special features
 Review of DoS attacks
 Important DoS attacks in UWSN
 Conclusions

DoS in Sensor Networks
Disrupt communication and cooperation
between nodes
 Decrease availability of the whole
network
 Waste precious resources (power)

Why Denial of Service so dangerous
Cheap
 Hard to detect
 Often precede the “real” attack
 Deadly for sensor nodes

Why care about it now?
Security integrated at every layer
 Have to ensure security at design time
 UWSN at its initial stage
 Adding security after the protocol is
“stable”

UWSN constraints
Not able to secure their communication
medium
 Low speed of the transmission (1500 m/s)
 Low data rate (5-20 kb/s)
 Limited bandwidth (around 30 KHz)
 High mobility (3-6 km/h)
 Environment 3D vs. 2D
 Physical constraints (pressure, corrosion)

Types of DoS
Physical Layer
 Jamming
 Tampering
Link Layer
 Collision
 Exhaustion
Types of DoS (Cont.)
Network Layer
 Neglect and greed
 Homing
 Misdirection
 Black holes
 Wormhole
Transport Layer
 Flooding
 Desynchronization
DoS in Physical Layer
1) Jamming
Constantly sending noise into channel
• Even if temporary, can be dangerous
•
Workaround: Switch to lower duty cycle
• Defense:
- Spread spectrum
- Try to alert other nodes about the attack
•
DoS in Physical Layer
2) Tampering
• Physically compromising sensor node
• Destruction or turning into a malicious
node
• Workaround: Complete failure of the
node, once compromised
• Defense: Hide the node
DoS in Link Layer
1) Collision
• Inducing a collision in section of the
transmitted packet
• Defense: No fully-effective found, because
of the initial assumption that nodes
should cooperate to avoid corruption of
others’ packets
DoS in Link Layer
2) Exhaustion
• Induce retransmissions
• Induce redundant traffic
Defense: Authentication
DoS in Network Layer
1) Neglect and greed
• Refuse to forward packets
• Give priority to its own traffic
Defense: Redundant paths
Dos in Network Layer
2) Homing
• Finding a privileged node and
compromising it
Defense: Encrypt message headers
Dos in Network Layer
3) Misdirection
• Send packets in different direction then
intended by the source node
Defense: Routing table updates, allowed
only by authorized nodes.
Dos in Network Layer
4) Black holes
• Advertising zero-cost links to itself
Defense:
- Redundant paths
- Authorization of updates of routing
tables
Dos in Network Layer
5) Wormholes
• Eavesdrop a packet and then release it in
remote location in the network
Defense: Geographic forwarding
DoS in Transport Layer
1) Flooding
• Flood a node with connection requests
Defense: Require authentication to create a
connection
DoS in Transport Layer
2) Desynchronization
• Forge message with sequence numbers or
flags that cause retransmission
Defense: Authenticate all the messages
Attacks Strongly Influencing UWSN
Jamming
- Limited bandwidth
- Simple and cheap to perform
 Collision
- The environment itself causes enough
errors

Attacks Strongly Influencing UWSN
Homing
- We will need to have some privileged
node, with greater computation power
 Wormhole
- The difference in propagation delay
between radio waves and sound

Conclusions
Security has to be considered at the
design time of protocols on every layer
 We will need to have a solution that will
attempt to provide defense from multiple
DoS attacks
 The security vs. energy efficiency trade-off

References (1)
Anthony D. Wood, John A. Stankovic
Denial of Service in Sensor Networks
• Anthony D. Wood, John A. Stankovic
A Taxonomy for Denial-of-Service Attacks in
Wireless Sensor Networks
• John Heidemann, Wei Ye, Jack Wills, Affan Syed
and Yuan Li
Research Challenges and Applications for
Underwater Sensor Networking
•
References (2)
Ian F. Akyildiz, Dario Pompili, Tommaso Melodia
State of the Art in Protocol Research for
Underwater Acoustic Sensor Networks
• Zhong Zhou, Jun-Hong Cui, and Amvrossios
Bagtzoglou
Scalable Localization with Mobility Prediction for
Underwater Sensor Networks
• John A. Stankovic
Research Challenges for Wireless Sensor
Networks
•
Thank you!