Port Scanning Port scanning can uncover a number of holes that a hacker could use for Exploits , In this short post i cant all types of port scans even though whatever i can i do for you Port Scanning is one of the most popular reconnaissance techniques attackers use to discover services they can break into. All machines connected to a Local Area Network (LAN) or Internet run many services that listen at well-known and not so well known ports. A port scan helps the attacker find which ports are available (i.e., what service might be listing to a port). Essentially, a port scan consists of sending a message to each port, one at a time. The kind of response received indicates whether the port is used and can therefore be probed further for weakness. Can I take legal action against port scanning? A Port scan is like ringing the doorbell to see whether someone’s at home. The police usually cant do anything about it. They have to wait until a crime is committed. The police might give it more consideration if the doorbell is repeatedly rung causing the homeowner to complain of harassment. Sometimes, if a computer system is affected too much by a port scan, one can argue that the port scan was, in fact, a denial-of-service (DoS) attack, which is usually an offense. The various techniques used in a port scan are summarized below. Port Scan – Port Numbers As you know, public IP addresses are controlled by worldwide registrars, and are unique globally. Port numbers are not so controlled, but over the decades certain ports have become standard for certain services. The port numbers are unique only within a computer system. Port numbers are 16-bit unsigned numbers.The port numbers are divided into three ranges: Well Known Ports (0 – 1023) Registered Ports (1024 – 49151) Dynamic and/or Private Ports (49152 – 65535) Well-Known Ports Ports numbered 0 to 1023 are considered well known (also called standard ports) and are assigned to services by the IANA (Internet Assigned Numbers Authority). Here are a few samples: echo – 7/tcp – Echo ftp-data – 20/udp – File Transfer [Default Data] ftp – 21/tcp – File Transfer [Control] ssh – 22/tcp – SSH Remote Login Protocol telnet – 23/tcp – Telnet domain – 53/udp – Domain Name Server www-http – 80/tcp – World Wide Web HTTP Non-Standard Ports By a non-standard port, we simply mean a port whose number is higher than 1023. In this range also, several services are “standard.” For example: wins – 1512/tcp # Microsoft Windows Internet Name Service radius 1812/udp # RADIUS authentication protocol Some malicious programs such as Trojans and Viruses have spread so wide that there are a number of ports that if found open, usually indicate that a system may have a virus. Wait for Port scan basic and advanced scanning methods
Posted on: Mon, 27 Jan 2014 02:54:07 +0000
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