Host-Based IDS

A host-based IDS (HIDS) resides on a particular computer or server and monitors activity only on that system. HIDS also called as system integrity verifiers as they benchmark and monitor the status of key system files and detect when intruder creates, modifies, or deletes files. It is efficient enough to monitor system configuration databases. Most of the HIDSs work on principle of configuration or change in management. The HIDS examines the files and logs for predefined events. The advantage of HIDS over NIDS is which it can be installed usually so that it can access information encrypted when traveling over network.

Advantages and Disadvantages of HIDSs

Advantages

-Can detect local events on host systems and detect attacks that may elude a network based IDS
- Functions on host system, where encrypted traffic will have been decrypted and is available for processing.
-Not affected by use of switched network protocols
-Can detect inconsistencies in how applications and systems programs were used by examining records stored in the audit logs.

Disadvantages

-Pose more management issues
-Vulnerable both to direct attacks and attacks against host operating system
-Does not detect multi host scanning, nor scanning of non-host network devices
-Susceptible to some denial of service attacks
-Can use large amounts of disk space
-Can inflict a performance overhead on its host systems