Chapter 30 ADP

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.

Decoy Port Scans

Decoy port scans are scans where the attacker has spoofed the source address. These are some decoy scan types:

•TCP Decoy Portscan

•UDP Decoy Portscan

•IP Decoy Portscan

Distributed Port Scans

Distributed port scans are many-to-one port scans. Distributed port scans occur when multiple hosts query one host for open services. This may be used to evade intrusion detection. These are distributed port scan types:

•TCP Distributed Portscan

•UDP Distributed Portscan

•IP Distributed Portscan

Port Sweeps

Many different connection attempts to the same port (service) may indicate a port sweep, that is, they are one-to-many port scans. One host scans a single port on multiple hosts. This may occur when a new exploit comes out and the attacker is looking for a specific service. These are some port sweep types:

•TCP Portsweep

•UDP Portsweep

•IP Portsweep

•ICMP Portsweep

Filtered Port Scans

A filtered port scan may indicate that there were no network errors (ICMP unreachables or TCP RSTs) or responses on closed ports have been suppressed. Active network devices, such as NAT routers, may trigger these alerts if they send out many connection attempts within a very small amount of time. These are some filtered port scan examples.

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TCP Filtered Portscan

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UDP Filtered Portscan

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IP Filtered Portscan

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TCP Filtered Decoy

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UDP Filtered Decoy

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IP Filtered Decoy

 

Portscan

 

Portscan

 

Portscan

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ZyWALL USG 100/200 Series User’s Guide