Describe different types of intrusions such as sql pl/sql, xml, and other injections.

Intrusion means unauthorized and harmful activities happening in your system. Any irregularities in the system is considered as intrusion and therefore monitored by administrators and can be detected using Intrusion Detection System.

Examples of Intrusion attacks in a network are:

Denial of Service (Dos) - denial of service means flooding the system causing it to crash and unable to respond to a service request. Normally, a DoS attack is facilitated by numbers of hosts sending enormous request to a victim computer. The requests can be in a form of code that would flood the system and making it to unresponsive.  Man in the Middle Attack (MiM) - a hacker would be in the middle of the communication between a client computer and a server computer. The hacker can mimic IPs within the network and steal information then sends it to the intended receiver.  SQL Injection - For websites that runs database like SQL, a code by the hacker can be added to the website and making him gained access to the database information successfully.