AWSN/19/Network security attacks/layer attacks

CLICK Here https://www.youtube.com/channel/UC-s9vNBHUJP3SEofXwrXccQ/?sub_confirmation=1 Layer wise Attacks in Wireless Sensor Networks  This section discusses about the WSN layer wise attack. Physical Layer Attacks Jamming  This is one of the Denial of Service Attacks in which the adversary attempts to disrupt the operation of the network by broadcasting a high-energy signal.  Jamming attacks in WSNs, classifying them as constant (corrupts packets as they are transmitted), deceptive (sends a constant stream of bytes into the network to make it look like legitimate traffic), random (randomly alternates between sleep and jamming to save energy), and reactive (transmits a jam signal when it senses traffic).  To defense against this attack, use spread-spectrum techniques for radio communication. Handling jamming over the MAC layer requires Admission Control Mechanisms. Radio Interference  Here, adversary either produces large amounts of interference intermittently or persistently. To handle this issue, use of symmetric key algorithms in which the disclosure of the keys is delayed by some time interval. Tampering or Destruction  Given physical access to a node, an attacker can extract sensitive information such as cryptographic keys or other data on the node.  One defense to this attack involves tamper-proofing the node’s physical package.  Self-Destruction (tamper-proofing packages) – whenever somebody accesses the sensor nodes physically the nodes vaporize their memory contents and this prevents any leakage of information. Data Link Layer Attacks Continuous Channel Access (Exhaustion)  A malicious node disrupts the Media Access Control protocol, by continuously requesting or transmitting over the channel. This eventually leads a starvation for other nodes in the network with respect to channel access.  One of the countermeasures to such an attack is Rate Limiting to the MAC admission control such that the network can ignore excessive requests, thus preventing the energy drain caused by repeated transmissions.  A second technique is to use time division multiplexing where each node is allotted a time slot in which it can transmit. Collision  This is very much similar to the continuous channel attack. A collision occurs when two nodes attempt to transmit on the same frequency simultaneously. When packets collide, a change will likely occur in the data portion, causing a checksum mismatch at the receiving end. The packet will then be discarded as invalid. A typical defense against collisions is the use of error-correcting codes. Unfairness  Repeated application of these exhaustion or collision based MAC layer attacks or an abusive use of cooperative MAC layer priority mechanisms, can lead into unfairness.  This kind of attack is a partial DOS attack, but results in marginal performance degradation.  One major defensive measure against such attacks is the usage of small frames, so that any individual node seizes the channel for a smaller duration only. Interrogation  Exploits the two-way request-to-send/clear-to-send (RTS/CTS) handshake that many MAC protocols use to mitigate the hidden-node problem.  An attacker can exhaust a node’s resources by repeatedly sending RTS messages to elicit CTS responses from a targeted neighbour node.  To put a defense against such type of attacks a node can limit itself in accepting connections from same identity or use Anti replay protection and strong link-layer authentication. Sybil Attack  In this attack, a single node presents multiple identities to all other nodes in the WSN. This may mislead other nodes, and hence routes believed to be disjoint with respect to node can have the same adversary node.  A countermeasure to Sybil Attack is by using a unique shared symmetric key for each node with the base station. Network Layer Attacks Sinkhole Attack  Sinkhole attacks normally occur when compromised node send fake routing information to other nodes in the network with aim of attracting as many traffic as possible. Hello Flood  This attack exploits Hello packets that are required in many protocols to announce nodes to their neighbors. A node receiving such packets may assume that it is in radio range of the sender.  A laptop class adversary can send this kind of packet to all sensor nodes in the network so that they believe the compromised node belongs to their neighbors. This causes a large number of nodes sending packets to this imaginary neighbour and thus into oblivion. Authentication is the key solution to such attacks. Such attacks can easily be avoided by verify bi-directionality of a link before taking action based on the information received over that link. Node Capture  Node capture attack is a serious attack through which an intruder can performs various operations on the network and can easily compromise the entire network. It is one of the hazardous attack in WSNs.