Cybersecurity Blue Team Toolkit

CHAPTER 5Monitoring with OSSEC

WHAT YOU WILL LEARN IN THIS CHAPTER:

• Log‐Based Intrusion Detection Systems
• Agents
• Log Analysis

Open Source Security (OSSEC) is a free, open‐source, host‐based intrusion detection system (HIDS). Daniel Cid, the author of OSSEC, often refers to it in the log analysis portion of OSSEC as a log‐based intrusion detection system (LIDS). Log analysis for intrusion detection is the process of using the recorded events to detect attacks on a specific environment.

With the proper agents installed on your assets and logs being processed by OSSEC, you meet the criteria for another CIS control. CIS Control 6 is the maintenance, monitoring, and analysis of logs. You must ensure that logging is enabled locally on your systems and it is actively being monitored. Sometimes logging is the only record or evidence of a successful attack. Without solid logs, an attack may go undetected, and damage can be ongoing for months, if not years. Not only can a LIDS protect against an external threat, it also can protect against an internal threat such as detecting a user who is violating an acceptable use policy (AUP).

Log‐Based Intrusion Detection Systems

On your hosts across your network, it is vital to monitor the current state of a machine, check the files that are stored on that machine (the log files), and check to make sure that these files have not been changed. OSSEC operates on the principle that attackers who are successful at exploiting a vulnerability and ...