Abstract
Most of the applications of wireless sensor networks have critical tasks to be fulfilled; thus they must be secured. Recent studies focus on securing the communication between sensors and with the base station. An adversary can launch various types of attack on WSN depending on its ability and objective. These attacks can be broadly classified into two categories: 1) layer-dependent, and 2) layer-independent. Layer-dependent attacks are specific to communication protocol layers. They mostly target a node's functionality such as routing, availability, time synchronization, and data aggregation. Layer-independent attacks are not restricted to any communication protocol layers. These attacks can be launched independent of the communication protocol stack. In this chapter, we study the various attacks possessed by WSN and classify them based on their strength, action, security requirements and impact at different layers of WSN. We define metrics to evaluate the characteristic, behavior, and dependency of these attacks followed a discussion on various counter-measures to defend them.
Top2. Security Requirements In Wsn
In applications, such as military, wild-life monitoring, and traffic monitoring, it is possible to secure the base station (BS). However, the major challenge is to protect the tiny sensors that are deployed either in the enemy territory, open space, or in hazardous areas. Therefore, the sensor nodes and their sensed data must be secured. A number of sophisticated and highly efficient security architectures are available for traditional networks. However, these are unsuitable for WSN due to following reasons. Security in sensor networks is resource constrained and depends on deployment characteristics. Asymmetric key cryptography becomes expensive for sensor networks due to limited energy resources. In this case, symmetric cryptography is a better choice for faster computation. However, symmetric key cryptographic techniques lack versatility compared to their counterparts. Sensor nodes cannot be equipped with tamper-resistant hardware due to low-cost node constraint. Therefore, it is assumed that nodes are also prone to physical attacks. Sensor nodes rely on wireless medium to communicate among themselves. This makes the task of an adversary easier to eavesdrop on network communication. An attacker also can inject malicious information into the wireless network with a little effort.
It is also requires that security mechanism supports large scale networks. Most common security frameworks do not support large number of users. Considering all the above cases, a secured WSN must satisfy the following security requirements (Claycomb & Shin, 2011):
- 1.
Information confidentiality and privacy,
- 2.
Data integrity,
- 3.
Entity authentication,
- 4.
Key distribution and management,
- 5.
Secure routing,
- 6.
Resilience to node capture,
- 7.
Secure data aggregation, and
- 8.
Intrusion detection.
In the following subsections, we discuss the above security requirements in details.
Key Terms in this Chapter
Attacker Class (AC): This defines the type of attacking node i.e., either a mote class or laptop class type node is required to launch an attack.
NNDUT: This is defined as the number of nodes directly under threat when a single instance of an attack is launched in the network by an adversary.
Parent Attack (PA): This defines whether any prior attack needs to be launched before performing an attack. TSO: This defines the set of security objective(s) affected by launching an attack.