ZyXEL ISG50-PSTN User Guide - Page 422

Chapter 26 ADP 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. • TCP Filtered Portscan • UDP Filtered Portscan • TCP Filtered Decoy Portscan • UDP Filtered Decoy Portscan • TCP Filtered Portsweep • UDP Filtered Portsweep • ICMP Filtered Portsweep • TCP Filtered Distributed Portscan • IP Filtered Distributed Portscan • IP Filtered Portscan • IP Filtered Decoy Portscan • IP Filtered Portsweep • UDP Filtered Distributed Portscan 422 ISG50 User's Guide