Security in wireless ad hoc sensor network (without physical access)

Question

I want to know without taking physical access, what are the methods that can steal the data in a node.

1. When talking about eavesdropping, how can an attacker sniff the packets? Do they need to listen to that node or listen to channel?
2. Is there any other way to get nodes data?
3. What happens when impersonation attacks happen? Can an attacker get all the data of particular node?
4. How can encryption can be used to secure communication? And is there any way to protect keys? If a hacker gets the key does that mean he gets the all?

Answer 1

Here you are talking of just an ad-Hoc wireless connection with/without internet connectivity is an important aspect which is unclear. Considering it to be with an Internet Connectivity then the usual WEP key is completely vulnerable. WPA-2 is preferred alternative. Also node data can be theft only if specific ports are left open. So that has nothing much to do with network here; instead iptables or firewall must me secured. On similar lines even if the key is lost to the hacker that doesn't guarantee he can take all your node data.

Answer 2

To answer question 1, it is the channel that is listened in on, and nodes can be identified by their MAC addresses. The information gathered from such channel listening on unencrypted data is limited, of course, by the communication done, at first, but information gathered can then be used for subsequent attacks on the endpoints.

Answer 3

1. If the nodes are communicating via 802.11, a wifi card in monitor mode + e.g. wireshark will be enough to capture all data within the wireless link range. If the data is not encrypted, the attacker can see it immediately.

2. Well one could e.g. start an attack on the routing protocol and try to trick the nodes to send all data via our node or a node we have previously compromised. Now you could take a look in data that is passing by. Take a look at this paper.

3. This pretty much depends on the routing protocol, the attacker might get some/all data.

4. If you gather the data from the sensors in a central point, you can encrypt the data with the public key of the entity that is collecting the data. This way only this entitiy could read it. If a key is compromised, you have to assume that all data is compromised as well.

Some more general info about attacks on wireless sensor networks can be found here.