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Chapter 15 Security
15.3.4 Port Scanning
An attacker scans device(s) to determine what types of network protocols or
services a device supports. One of the most common port scanning tools in use
today is Nmap.
Many connection attempts to different ports (services) may indicate a port scan.
These are some port scan types:
• TCP Portscan
• UDP Portscan
• IP Portscan
An IP port scan searches not only for TCP, UDP and ICMP protocols in use by the
remote computer, but also additional IP protocols such as EGP (Exterior Gateway
Protocol) or IGP (Interior Gateway Protocol). Determining these additional
protocols can help reveal if the destination device is a workstation, a printer, or a
router.
15.3.5 ICMP Flood Attack
Flood attacks saturate a network with useless data, use up all available
bandwidth, and therefore make communications in the network impossible.
15.3.6 Smurf Attack
A smurf attacker (A) floods a router (B) with Internet Control Message Protocol
(ICMP) echo request packets (pings) with the destination IP address of each
packet as the broadcast address of the network. The router will broadcast the
ICMP echo request packet to all hosts on the network. If there are numerous
hosts, this will create a large amount of ICMP echo request and response traffic.
If an attacker (A) spoofs the source IP address of the ICMP echo request packet,
the resulting ICMP traffic will not only saturate the receiving network (B), but the
network of the spoofed source IP address (C).
Figure 124 Smurf Attack
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P-794H User's Guide
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