Layer 3 Security Threats
At the network layer of OSI model, we find the Internet Protocol (IP) with ICMP being a part of the Internet Protocol. Layer 3 is vulnerable to multiple DoS attacks and privacy disclosure attacks.
Packet Sniffing
We discussed packet sniffing earlier in this chapter and how attackers in a switched network can sniff packets that don't belong to them. If the network is not switched (e.g. a Hub is used) packet sniffing becomes a lot easier.
Sniffing packets means capturing IP traffic using tools like dsniff, tcpdump, ethereal, etc. Because data from upper layers is encapsulated into IP packets, all the information from those layers can be disclosed when analyzing (decapsulating) IP packets.
Protocols like POP3, SMTP, SNMP, etc., ...
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