Wireless sensor networks consist of distributed autonomous devices that can monitor various environmental conditions. Securing these networks is challenging due to constraints on sensors' processing, memory, and battery power. Attacks on wireless sensor networks can target security mechanisms or routing mechanisms. Common attacks include denial of service through jamming, spoofing and altering information in transit, replication attacks, and physical node destruction. Effective security schemes must provide data confidentiality, integrity, and freshness given sensors' limitations. Developing efficient detection of compromised nodes reporting false data while ensuring holistic security in wireless sensor networks remains an important research challenge.

1. SECURITY IN WIRELESS
SENSOR NETWORKS
BY
RABIA ASHRAFI
M.TECH(CSE)

2. Wireless Sensor Networks
• A wireless network consisting of spatially
distributed autonomous devices.
• Basic idea is to wide spread the tiny sensing devices
which are capable of sensing some.
• Can monitor temperature, pressure, humidity, soil
makeup, vehicular movement, noise levels, lighting
conditions, the presence or absence of certain kinds
of objects or substances, mechanical stress levels on
attached objects, and other properties .

3. Issues to concentrate on
• The routing strategies get more preference, the
security issues are yet to receive extensive focus.
• Explore the security issues and challenges, discuss
crucial parameters that require extensive
investigations.
• Talk about cryptography, steganography and other
basics of network security

4. • Discuss various types of threats and attacks against
wireless sensor network .
• Discuss related work and proposed schemes
concerning security in WSN and introduce the view
of holistic security in WSN.
Cont’d

5. Security Schemes in Wireless Sensor
Networks
• Authentication, integrity, privacy, no repudiation, and
anti-playback.
• For secure transmission of various types of
information over networks, several cryptographic,
steganography and other techniques are used.

6. Cryptography
• Encryption-decryption techniques meant for the
traditional wired networks are not capable in WSN.
• Wireless sensor networks consist of tiny sensors
which really suffer from the lack of processing,
memory and battery power.
• Applying any encryption scheme requires
transmission of extra bits.

7. Steganography
• Cryptography aims at hiding the main content of a
message, steganography aims at hiding the present
existence of the message.
• Steganography is the art of covert communication by
embedding a message into the multimedia data
(image, sound, video, etc.).
• Objective of steganography is to modify the carrier in
a way that is not perceptible and hence, it looks just
like ordinary message.

8. Securing wireless sensor networks is not directly related to
steganography and processing multimedia data (like audio,
video) with the inadequate resources of the sensors is difficult.

9. Security Threats and Issues in Wireless
Sensor Networks
• Wireless networks are usually more open to various
security threats as unguided transmission medium is
more open to security attacks than those of the
guided transmission medium.

10. Attacks in Wireless Sensor Networks
Attacks against wireless sensor networks could be
broadly considered from two different levels of
views.
1. The attack against the security mechanisms
2. Against the basic mechanisms (like routing
mechanisms).

11. Denial of Service
• A standard attack on wireless sensor networks is to
jam a node or set of nodes.
• Jamming, the transmission of a radio signal that
interferes with the radio frequencies being used by
the sensor network.
• Two forms: constant jamming, and intermittent
jamming.

12. • Constant jamming involves the complete jamming of
the entire network. No messages are able to be sent or
received.
• If the jamming is only intermittent, then nodes are
able to exchange messages periodically, but not
consistently.
• Can have a detrimental impact as the messages may
be time sensitive.
Cont’d

13. Transport Layer
Attacks :
• Transport layer susceptible to flooding.
• Flooding can be as simple as sending many
connection requests to a susceptible node.
Prevention :
• Resources must be allocated to handle the connection
request.
• Eventually a node’s resources will be exhausted, thus
rendering the node useless.

14. Attacks on Information in transit
• In a sensor network, sensors monitor the changes of
specific parameters or values and report to the sink
according to the requirement.
• While sending the report, the information in transit
may be altered, spoofed, replayed again or vanished.

16. Sybil Attack
• In such a situation, a node can pretend to be
more than one node using the identities of
other legitimate nodes .
• This type of attack where a node forges the
identities of more than one node is the Sybil
attack.
• Degrades integrity of data, security and
resource utilization that the distributed
algorithm attempts to achieve.

17. Black hole/Sinkhole Attack
• Malicious node acts as a black hole to attract all the
traffic in the sensor network.
• Attacker listens to requests for routes then replies to
the target nodes that it contains the high quality or
shortest path to the base station.

18. Hello Flood Attack
• Uses HELLO packets as a weapon to convince the
sensors in WSN.
• Attacker with a high radio transmission range and
processing power sends HELLO packets to a number
of sensor nodes.
• Sensors are thus persuaded that the adversary is their
neighbor.
• Victim nodes try to go through the attacker.

19. Wormhole Attack
• Attacker records the packets (or bits) at one location
in the network and tunnels those to another location.
• The tunneling or retransmitting of bits could be done
selectively.
• Attack does not require compromising a sensor in the
network rather, it could be performed even at the
initial.

20. Time correlation attack
• Adversary generates events and monitors to whom a
node sends its packets.
• To generate an event, the adversary could simply
generate a physical event that would be monitored by
the sensor(s) in the area (turning on a light, for
instance).

21. Node Replication Attacks
• Attacker seeks to add a node to an existing sensor
network by copying (replicating) the node ID of an
existing sensor node .
• Packets can be corrupted or even misrouted.

22. Physical Attacks
• Sensor networks typically operate in hostile outdoor
environments.
• The small form factor of the sensors, both of these
together with the unattended and distributed nature
of their deployment make them highly susceptible to
physical attacks, i.e., threats due to physical node
destructions.

23. Security Schemes for Wireless Sensor
Networks
• Gives an analysis of secure routing in wireless sensor
networks and studies how to design secure distributed
sensor networks
• It studies Denial of service attacks against different
layers of sensor protocol stack.
• JAM presents a mapping protocol which detects a
jammed region in the sensor network and helps to
avoid the faulty region to continue routing within the
network.

24. Data Confidentiality
• A sensor network should not leak sensor readings to its
neighbors.
• In many applications nodes communicate highly sensitive
data, e.g., key distribution, is extremely important to build a
secure channel in a wireless sensor network.
• Public sensor information, such as sensor identities and
public keys, should also be encrypted to some extent to
protect against traffic analysis attacks.
• The standard approach for keeping sensitive data secret is to
encrypt the data with a secret key that only intended
receivers possess, thus achieving confidentiality.

25. Data Integrity
• With the implementation of confidentiality, an
adversary may be unable to steal information.
• This doesn’t mean the data is safe. The adversary can
change the data, so as to send the sensor network into
disarray.
• Thus, data integrity ensures that any received data has
not been altered in transit.

26. Data Freshness
• Need to ensure the freshness of each message.
• Informally, data freshness suggests that the data is
very much recent, and it ensures that no old messages
have been replayed.
• This requirement is especially important when there
are shared-key strategies.

28. Conclusion
• Most of the attacks against security in wireless sensor
networks are caused by the insertion of wrong
information by the nodes which are agreed or
compromised within the network.
• For defending the inclusion of these false reports by
compromised nodes, a mean is required for detecting
these false reports.
• However, developing such a detection mechanism and
making it efficient represents a great research
challenge.
• Again, ensuring the holistic security in wireless sensor
network is one of the major research issue.

29. THANK YOU