WSN Security (Draft)

1. WSN Security (Draft) Moh’d Abidalrahman

2. WSN Security • Too... many types of attacks!! With lots of (overlapping) details…. • In this presentation. We will have an overview of the most serious attacks. • Providing security mechanisms against these attacks is so difficult.

3. Why Security is difficult? • Sensor Node Constraints • Battery • CPU power • Memory • Networking Constraints and Features • Wireless • Ad hoc • Unattended • Sensor network protocols have not been designed with security as a goal

4. Outline • Passive Information Gathering • Subversion of a Node • False Node and malicious data • HELLO floods Attack. • Sinkhole attack. • Wormhole attack. • The Sybil Attack. • Denial of Service Attack.

5. Passive Information Gathering • An intruder with an appropriately powerful receiver and well designed antenna can easily pick off the data stream. • Interception of the messages containing the physical locations of sensor nodes (attacker can locate the nodes and destroy them). • An adversary can observe the application specific content of messages and use them an another type of attack • message IDs • Sequence numbers • timestamps • etc...

6. Subversion of a Node • A particular sensor might be captured. • Information stored on it (such as the security keys) might be obtained by an adversary. • How to exclude that node, and that node only, from the sensor network???

7. False Node and malicious data • Add a node to the system that feeds false data or prevents passing true data. • By spoofing, altering, or replaying routing information, adversaries may be able to • create routing loops • attract or repel network traffic • extend or shorten source routes • generate false error messages • partition the network • increase end-to-end latency • etc… • Can destroy the whole network or • Take it over (more dangerous)

8. HELLO floods attack • Protocols that use HELLO packets to announce to neighbors • Assumption: the sender of a received packet is within normal radio range • False! A powerful transmitter could reach the entire network. • Traffic from nodes in the range will be drawn through adversary. • Nodes far away from the adversary would be sending packets to no one. • The network is left in a state of confusion.

9. Sinkhole attacks • Goal is to attract nearly all the traffic from a particular area through a compromised node, creating a sinkhole with the adversary at the center. • Sinkhole attacks typically work by making a compromised node look “especially attractive” to surrounding nodes with respect to the routing algorithm.

10. Sinkhole attacks • For instance, an adversary could spoof or replay an advertisement for an extremely high quality route to a base station. • Each neighbouring node will forward packets destined for a base station through the compromised node. • They will propagate the attractiveness of the route as well. • Effectively, the adversary creates a large “sphere of influence” attracting all traffic destined for a base station from nodes several hops away from the compromised node.

11. Wormhole attacks • An adversary tunnels messages received in one part of the network over a low latency link and replays.

12. Wormhole Attack • The attacker can have no key material. All it requires is two transceivers and one high quality out-of-band channel • An adversary could convince nodes who would normally be multiple hops from a base station that they are only one or two hops away via the wormhole. • This can create a sinkhole: since the adversary on the other side of the wormhole can artificially provide a high quality route to the base station. • potentially all traffic in the surrounding area will be drawn through sinkhole if alternate routes are significantly less attractive.

13. The Sybil Attacks • A single node presents multiple identities to other nodes in the network. • Can be used to launch more advanced attacks: • Routing • Distributed Storage • Data Aggregation • Voting • Fair Resource Allocation • Misbehaviour Detection

14. The Sybil Attacks • Distributed Storage • Defeat replication and fragmentation mechanisms • Routing • Attack routing algorithm • Geographic routing • Evade misbehavior detection mechanisms

15. The Sybil Attacks • Data Aggregation • With enough Sybil nodes, an attacker may be able to completely alter the aggregate reading. • Voting • Depending on the number of identities the attacker owns, he may be able to determine the outcome of any vote. • Either claim a legitimate node is misbehaving or Sybil nodes can vouch for each other…

16. The Sybil Attacks • Fair Resource Allocation • Using Sybil attack, a malicious node can obtain an unfair share of any resource shard in per-node manner. • Consequently, cause DoS to legitimate node, and also give the attacker more resources to perform attacks. • Misbehavior Detection • Sybil nodes could “spread the blame” . • Even action is taken to revoke the offending nodes, the attacker can continue using new Sybil identities to misbehave.

18. Denial of Service Attacks • A denial of service attack is "any event that diminishes or eliminates a network‘s capacity to perform its expected function.“ • Musfeq will explain them in detail.