Intrusion Detection System

INTRUSION DETECTION SYSTEM (IDS)

An Intrusion detection system (IDS) is software and/or hardware designed to detect unwanted attempts at accessing, manipulating, and/or disabling computer systems, mainly through a network, such as the Internet. These attempts may take the form of attacks, as examples, by crackers, malware and/or disgruntled employees. An IDS cannot directly detect attacks within properly encrypted traffic.

An intrusion detection system is used to detect several types of malicious behaviors that can compromise the security and trust of a computer system. This includes network attacks against vulnerable services, data driven attacks on applications, host based attacks such as privilege escalation, unauthorized logins and access to sensitive files, and malware (viruses, trojan horses, and worms).

Types of Intrusion-Detection systems

There are three main types of systems in which IDS can be used :                                           network, applications and hosts

Network intrusion detection system (NIDS)

It is an independent platform which identifies intrusions by examining network traffic and monitors multiple hosts. Network Intrusion Detection Systems gain access to network traffic by connecting to a hub, network switch configured for port mirroring, or network tap. An example of a NIDS is Snort.

Application protocol-based intrusion detection system (APIDS)

It consists of a system or agent that would typically sit within a group of servers, monitoring and analyzing the communication on application specific protocols. For example, in a web server with a database this would monitor the SQL protocol specific to the middleware/business logic as it transacts with the database.

Host-based intrusion detection system (HIDS)

It consists of an agent on a host which identifies intrusions by analyzing system calls, application logs, file-system modifications (binaries, password files, capability/acl databases) and other host activities and state. An example of a HIDS is OSSEC.