Page 102 - From Smart Grid to Internet of Energy

Smart metering and smart monitoring systems Chapter 2 87

Authorization enables users, customers and devices to get right to access
specific resources and applications. The authorization control ensures pre-
vention of intentional attacks targeting system security and unauthorized
intrusions to the system. The authorization process is accomplished by
assigning specified roles to user types, devices, and several different privi-
leges are set. The AMI infrastructure will be exposed to violating attacks in
case of authorization control lacks. The digital certificates, PKI, and AES
algorithms can be used for authorizing users and devices through AMI sys-
tem [5, 18, 19].
The major vulnerabilities of AMI system are listed as unencrypted area net-
work traffic, bus sniffing, tampering, improper cryptography, denial-of-service
(DoS) attacks, and authentication weakness.

2.4.2.2 Security threats of AMI networks
The security threats targeting AMI networks are investigated regarding to each
network layer in seven-layer OSI model as a communication network. There-
fore, the layer attacks are listed as physical layer attacks, link layer attacks, net-
work layer attacks, transport layer attacks, application layer attacks besides IP
based and other specific attacks. PHY attacks include tampering, damaging or
breaking down of metering device and AMI infrastructure. These threats can be
coped with tamper resistant and damage-free devices transmitting alerts and
alarms during intrusion detection.
The link layer enables multicasting by allowing nodes to connect and dis-
connect to network, and security is enhanced by this way. MAC protocols
are in charge for channel allocating and deploying available resources to nodes.
The MAC layer attacks and intrusions are prevented by specified protocols that
are operating identification filtering. The network layer attacks mostly target
traffic flow by changing routing tables that are required to deliver transmitted
message to destinations. The attacker changes routing table to change original
traffic flow to a specific route and then generates modified message or informa-
tion to cause traffic jam. The major network layer attacks include DoS attacks,
routing black holes, and wormholes. The DoS attacks aim to cause disturbances
on network traffic and eavesdropping on transmitted data. The routing black
holes are based on hacking a single node and then directing all network traffic
to hacked node. The wormholes target to create tunneling to change network
direction to enable attacker to monitor network traffic. The IP is responsible
to sustain confidentiality and authorization in smart grid communication net-
works. Therefore, cyber-attacks against confidentiality target IP stacks for
spoofing, convergence and spying. Transport layer attacks are like IP attacks
since it is managed by TCP and UDP protocols. The security of AMI networks
can be ensured by use of data encryption methods as discussed earlier. The data
encryption is performed by using symmetric or asymmetric key cryptography
that transmitter and receiver uses the same key in symmetric cryptography