ICMP AND FTP KNOWLEDGE

ICMP 'Ping' (Internet Control Message Protocol) ICMP is one of the main protocols that make the Internet work. It standards for Internet Control Message Protocol. 'Ping' is one of the commands that can be sent to a computer using ICMP. Ordinarily, a computer would respond to this ping, telling the sender that the computer does exist. This is all pings are meant to do. Pings may seem harmless enough, but a large number of pings can make a Denial-of- Service attack, which overloads a computer. Also, hackers can use pings to see if a computer exists and does not have a firewall (firewalls can block pings).

If a computer responds to a ping, then the hacker could then launch a more serious form of attack against a computer.
FTP (File Transfer Protocol) FTP is a standard Internet protocol, standing for File Transfer Protocol. You may use it for file downloads from some websites. If you have a web page of your own, you may use FTP to upload it from your home computer to the web server. However, FTP can also be used by some hackers... FTP normally requires some form of authentication for access to private files, or for writing to files
FTP backdoor programs, such as-
Doly Trojan
Fore
Blade Runner
simply turn your computer into an FTP server, without any authentication.
rpc.statd
This is a problem specific to Linux and Unix. The problem is the infamous unchecked buffer overflow problem. This is where a fixed amount of memory is set aside for storage of data. If data is received that is larger than this buffer, the program should truncate the data or send back an error, or at least do something other than ignore the problem. Unfortunately, the data overflows the memory that has been allocated to it, and the data is written into parts of memory it shouldn't be in. This can cause crashes of various different kinds. However, a skilled hacker could write bits of program code into memory that may be executed to perform the hacker's evil deeds.