# Clone Node Detection Attacks and Mitigation Mechanisms in Static Wireless Sensor Networks
## 3 Cybersecurity Attacks in Wireless Sensor Networks
### Classification of WSNs Attacks and Security Issues  
Attacks on a sensor network can be classified into three main categories:  
1. Identity attacks,
2. Routing attacks and,
3. Network intrusion. In the first category, as its name says, the carried action intends to steal the identities of legitimate nodes performing in the sensor network. Based on the carried action, we can say that the identity attacks are _Sybil_ attack and _Clone node_ attack. In a Sybil attack, the wireless sensor network is destabilized by a malicious node (illegitimate node), which forges a large number of fake identities to create confusion and perturb the network's protocols. On the other hand, a _node replication attack_ is defined as an attempt by the attacker to add one or more nodes to the WSN that use a similar ID as another node in the network. Sometimes there is a confusion of differentiation between the Sybil and replication attacks. A clear definition can be summarized as:  
In Sybil attacks, a single node exists with thousands of identities, while in node replication attacks (or node clone attacks), multiple nodes are present with the same identity. Routing attack: this category of attack intends to place the villain nodes on a routing path from a source to the sink that may attempt to discard legitimate data packets. This type of attack is usually called a _sinkhole attack_ since it is dealing with the sink (base station). Some people even call the routing attack \"_false routing information attack, wormholes, and selective forwarding attack_\". The attacker generates a large range of influence, which will attract all traffic destined for the sink from nodes that may be few leaps away from the illegitimate node, which is known as a _sinkhole attack_. _False routing attack_ can be defined as the injection of fake routing control packets into the network system. In the _wormhole attack_, two or more pernicious, spiteful conspiring nodes produce a higher-level virtual tunnel in the network, which is used to send packets between the tunnel endpoints. The compromised node (illegitimate) may refuse forward or forward selective packets at some points; hence, this situation is called _selective forwarding attack_. Network intrusion: as its name says, it is any action that penetrates the network without authorization. Wireless Sensor Network Specific Security Issues  
All the attacks mentioned in the previous section are considered as some security issues that WSN may suffer. In addition to that, there is a novel attack introduced against the sensor networks named _HELLO flood attack_. In this attack, the nodes can be induced by the attacker to trust that he is its nearby neighbor. Thus, in this situation, this can send fake data with high transmission power. Plenty of packets request nodes to distribute, broadcast or spread HELLO packets by presuming that they are neighbor nodes. The result is that, when a node reaches such a packet, it will assume that the packet is within the radio interval of the sender. Acknowledgment Spoofing: In this attack, the goal is to prove to the sender that a non-working node (dead node) still exists or to prove that a weak link is strong. That being said, an attacker can eradicate data that are transferring to these non-working nodes, or the weak links. The attacker can even eavesdrop on packets, which are sent to the living nodes, and can pinpoint which nodes are weak or dead. Jamming attack: This type of attack is one of the severe threats to wireless sensor networks using the IEEE 802.15.4 standard. In the WSNs system, a jammer is considered as an entity or someone who is intentionally and deliberately trying to pry into the transmission and reception of the wireless communications physically. This attack is a kind of DoS attack, which stops other nodes (legitimate nodes) from using the channel to communicate by keeping that channel busy. (For more information, please see [10, 11] for a general view about attacks and countermeasures in sensor networks).