3.4 Selective Forwarding attackIt i

3.4 Selective Forwarding attack
It is a situation when certain nodes do not forward many of the
messages they receive. The sensor networks depend on repeated
forwarding by broadcast for messages to propagate throughout
the network.
3.5 Sinkhole attacks
In a sinkhole attack, the adversary‟s aim is to lure nearly all the
traffic from a particular area through a compromised node,
creating a metaphorical sinkhole with the adversary at the center
[4]. Sinkhole attacks typically work by making a compromised
node look especially attractive to surrounding nodes with respect
to the routing algorithm.
Sinkhole attacks are difficult to counter because routing
information supplied by a node is difficult to verify.
As an example, a laptop-class adversary has a strong power radio
transmitter that allows it to provide a high -quality route by
transmitting with enough power to reach a wide area of the
network [4].
3.6 Passive Information Gathering
An intruder with an appropriately powerful receiver and well
designed antenna can easily pick off the data stream.
Interception of the messages containing the physical locations of
sensor nodes allows an attacker to locate the n odes and destroy
them [7] [8]. Besides the locations of sensor nodes, an adversary
can observe the application specific content of messages
including message IDs, timestamps and other fields.
3.7 Node Capturing
A particular sensor might be captured, and information stored on
it might be obtained by an adversary [7][8].
3.8 False or Malicious Node
Most of the attacks against security in wireless sensor networks
are caused by the insertion of false information by the
compromised nodes within the network [8].
3.9 Hello flood attacks
The Hello flood attacks can be caused by a node which
broadcasts a Hello packet with very high power, so that a large
number of nodes even far away in the network choose it as the
parent [10]. All messages now need to be routed multi-hop to
this parent, which increases delay.