Wireless Ad Hoc & Sensor Networks Wireless Ad Hoc & Sensor - PowerPoint PPT Presentation

Outline Wireless Ad Hoc & Sensor Networks Wireless Ad Hoc & Sensor Networks • Introduction - Security • Security challenges in Ad Hoc Networks y g • Threats and Attacks • Security Solutions Security Solutions – Cryptography Schemes and Key Management • Cryptography functions yp g p y • Key management approaches • Key management in Ad Hoc Networks WS 2010/2011 WS 2010/2011 – Routing Protocols Security – Soft security mechanisms Prof. Dr. Dieter Hogrefe • Summary S Dr. Omar Alfandi 2 What is Security in Wireless Ad Hoc Networks (1/2) What is Security in Wireless Ad Hoc Networks (2/2) • Confidentiality • Non-repudiation – Protection of confidential information – Ensure that the originator of communications can’t deny it later communications can t deny it later from unauthorized user from unauthorized user Integrity Authentication • Authenticity • Integrity Integrity v Authentication – Verify and validate the identity claimed y y – Guarantee that information being g v v transferred (IP Headers, Source Route) by a node Confidentiality is not tampered  Cryptographic schemes : digital Confidentiality  Spread spectrum digest checksums  Spread spectrum, digest, checksums signature, certificates,… signature, certificates,… Accessibility A ibilit and encryption • Privacy Accessibility Privacy • Availability – Prevent not authorized disclosure of Privacy location of nodes, topology of network – Ensure the survivability of the network services despite of various attacks and traffic  Access control mechanisms  usually accomplished by encryption y p y yp 3 4

Security Challenges in Ad Hoc Networks Outline • Introduction • Shared broadcast radio channel • Security challenges in Ad Hoc Networks y g • Insecure operational environment Insecure operational environment • Threats and Attacks • Lack of central authority • Security Solutions Security Solutions • Lack of association Lack of association – Cryptography Schemes and Key Management • Limited resource availability • Cryptography functions yp g p y • Physical vulnerability • Physical vulnerability • Key management approaches • Key management in Ad Hoc Networks  Security in Ad Hoc networks is an y – Routing Protocols Security essential component for basic network functions like packet – Soft security mechanisms forwarding and routing forwarding and routing • Summary S 5 6 Threats and Attacks Outline • Major Attacks Classification • Introduction – Passive attacks • Security challenges in Ad Hoc Networks y g Misbehaving node obtains exchanged data or learns important • Threats and Attacks information by monitoring and listening without disrupting the operation of the communication. e.g.: p g • Security Solutions Security Solutions • Selfish node that does not forwarding packets of other nodes in – Cryptography Schemes and Key Management order to save energy, but expect others to forward its packet! • Cryptography functions yp g p y • Key management approaches – Active attacks • Key management in Ad Hoc Networks involves information interruption or modification and therefore – Routing Protocols Security disrupting the normal functionality of the Ad hoc Networks e.g.: • Malicious node that aims at damaging the communication and – Soft security mechanisms finally the whole network y • Summary S 7 8

Threats and Attacks Threats and Attacks Attacks according to protocol stack: Att k di t t l t k • Another Attacks Classification – External: attacks are carried on by nodes outside of the network – Internal: attacks are carried on by nodes inside the network attacks are carried on by nodes inside the network • Internal attacks are more severe than external attacks, Internal attacks are more severe than external attacks, since insider: – Has privileged access rights – Knows valuable and secret information 9 10 Physical Layer Attacks Network Layer Attacks • Eavesdropping: Wormhole attack • An attacker may directly send – Signals broadcast over airwaves can be easily intercepted with Route Request packets to Route Request packets to receivers tuned to the proper frequency. i t d t th f their destination through S 1 S 4 S 8 S 11 • Jamming: the wormhole. – malicious powerful transmitter sends random noise and as malicious powerful transmitter sends random noise and as • • When neighbors of the When neighbors of the S 12 S 5 S 2 S 6 S 9 destination node hear the useless signals making other nodes unable to communicate. request, they will forward it S 13 • Impersonating: p g and discard all other Route and discard all other Route S 10 S S S 3 S S 7 – fake messages and routing information can be injected into Request packets from that node. network. • • The result of this is that no The result of this is that no other paths except those through the wormhole can be found. found 11 12

Network Layer Attacks Network Layer Attacks Blackhole attacks • Byzantine attack – Attackers perform creating routing loops, forwarding packets • An attacker advertises itself as having good paths (e.g. through non-optimal paths, or selectively dropping packets th h ti l th l ti l d i k t shortest path) to destination • Information disclosure • It causes all nodes around it to route packets towards it – Attacker may leak confidential or important information such as Attacker may leak confidential or important information such as • Then it discards all the packets it is asked to forward information about network topology, nodes location or optimal route to unauthorized node • Resource consumption Intention of the attacker – An attacker can attempt to consume battery life by unnecessary • Hindering the path-finding request for route, or by forwarding unnecessary packets to the request for route or by forwarding unnecessary packets to the • Intercepting all data packets victim node 13 14 Network Layer Attacks (Routing Attacks) Network Layer Attacks (Routing Attacks) • Routing messages flooding attack: Rushing attack – Hello flooding, RREQ flooding, Ack flooding, … • attacker form a wormhole. • Routing table overflow attack: • the tunneled packets can propagate faster. – An attacker can simply send excessive route advertisements to • rushing can act as an effective DoS against on-Demand overflow the victim’s routing table (Proactive Routing Algorithms) overflow the victim s routing table.(Proactive Routing Algorithms) Routing Protocols. • Routing cache poisoning attack: D M – An attacker could broadcast spoofed packets with source route An attacker could broadcast spoofed packets with source route to X via itself; thus, neighboring nodes that overhear the packet may add the route to their route caches. • Packet replication: S – Adversary replicates stable packet . This consume additional bandwidth and battery power and cause confusion in routing bandwidth and battery power and cause confusion in routing process. 15 16

Transport Layer Attacks Multilayer Attacks Session hijacking: • That could occur in any layer of the protocol stack: – Denial of service (DoS): an adversary attempts to prevent • Adversary takes control over a session between two authorized users from accessing the service th i d f i th i nodes: • Jamming: malicious powerful transmitter sends random noise and – attacker spoofs the victim’s IP address as useless signals making other nodes unable to communicate – determines the correct sequence number that is expected by d t i th t b th t i t d b • SYN flooding: an adversary send a large number of SYN packets to the target a victim node – then performs a DoS attack on the victim p • Distributed DoS attack: several adversaries attack a service at the same time – thus the attacker impersonates the victim node and continues – Impersonation: adversary pretends to be another node the session with the target Assumed route – Device tampering: mobile device get damaged or stolen easily Device tampering: mobile device get damaged or stolen easily • Application layer attack: Repudiation: Denial of A B Actual route participation in all or part of communications participation in all or part of communications Attacker 17 Security Solutions Outline • Security is not a single layer issue but, it is a • Introduction Multi-Layer/ Cross-Layer issue • Security challenges in MANETs y g • Threats and Attacks • To have comprehensive security, major solutions are: • Security Solutions Security Solutions – Cryptography Schemes and Key Management – Cryptography Schemes and Key Management – Routing Protocols Security • Cryptography functions yp g p y – Soft security mechanisms Soft security mechanisms • Key management approaches • Key management in Ad Hoc Networks – Routing Protocols Security – Soft security mechanisms • Summary S 19 20