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Explore the fundamentals of Intrusion Detection Systems (IDSs), covering event logging, alarm management, analysis methods, and data transfer modes. Learn about distributed IDSs, NIDS placement, and securing manager-agent communication for effective network security.
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Figure 10-4: Intrusion Detection Systems (IDSs) • IDSs • Event logging in log files • Analysis of log file data • Alarms • Too many false positives (false alarms) • Too many false negatives (overlooked incidents) • Log files for retrospective analysis by humans
Figure 10-4: Intrusion Detection Systems (IDSs) • Elements of an IDS (Figure 10-5) • Event logging • Analysis method • Action • Management
Figure 10-5: Elements of a Simple IDS Management: Configuration, Tuning Action: Alarms, Queries, Reports Analysis: Attack Signatures and Heuristics Logging (Data Collection): Individual Events are Time-Stamped Log is Flat File of Events
Figure 10-4: Intrusion Detection Systems (IDSs) • Distributed IDSs (Figure 10-6) • Managers • Agents • Distribution of functionality between agents and managers (analysis and action)
Log File FW Log Figure 10-6: Distributed IDS Manager Site Host IDS Agent Log File Transfer in Batch Mode or Real Time Internet Connection Agent Agent Agent Main Firewall Internal Switch-Based Network IDS Stand-Alone Network IDS
Figure 10-4: Intrusion Detection Systems (IDSs) • Distributed IDSs (Figure 10-6) • Batch versus Real-Time Data Transfer • Batch mode: Every few minutes or hours; efficient • Real-time: As events occur or shortly afterward; little or no data loss if attacker eliminates log file on agent’s computer
Figure 10-4: Intrusion Detection Systems (IDSs) • Distributed IDSs (Figure 10-6) • Secure manager-agent communication • Vendor’s automatic updates with secure communication • Network IDSs (NIDSs) • Capture packets • Stand-alone NIDS collects data for only its portion of the network • Switch or router NIDSs can collect data on all ports
Figure 10-4: Intrusion Detection Systems (IDSs) • Network IDSs (NIDSs) • NIDS placement • Between main firewall and internal or external network for relevant or all attacks • At internal points to detect internal mischief • Weaknesses • Blind spots in network where no NIDS data is collected • Cannot filter encrypted packets