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Chapter 7. Intrusion Detection. Objectives. In this chapter, you will: Understand intrusion detection benefits and problems Learn about network intrusion detection Learn about host intrusion detection Recognize the importance of honeypots Learn how operators analyze and respond to events.
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Chapter 7 Intrusion Detection
Objectives In this chapter, you will: • Understand intrusion detection benefits and problems • Learn about network intrusion detection • Learn about host intrusion detection • Recognize the importance of honeypots • Learn how operators analyze and respond to events
Intrusion Detection Overview • Layered detection to proactively monitor networks and systems • 1st layer: Network monitoring • 2nd layer: System (host) monitoring • 3rd layer: Trending and analysis • 4th layer: Current news and information
Intrusion Detection Overview • Recording activity to provide another mechanism with monitoring • IDS • Network device logging (e.g., firewalls, routers, etc.) • System logging
Intrusion Detection Overview • Distraction and setting traps to entice attackers for monitoring purposes • Emulating OS or applications • Delaying network responses • Displaying deceptive error messages • Restricting the number of connections • Restricting the time allowed for connections • Running all applications as a non-privileged user
Intrusion Detection Overview • False positives are biggest problem for IDS • Some solutions include: • Filtering • Summation of events • Rule modification
Network Intrusion Detection • Sensors • Hardware devices • Software applications • Commercial vendors: Cisco, Enterasys, ISS • Freeware: Snort
Network Intrusion Detection • Sensor placement • Use multiple sensors • Do not overwhelm sensors with traffic • Place at every Internet access point • Place at every extranet access point • Place on both sides of a firewall • Do not flood network with NIDS traffic
Network Intrusion Detection • Sensor deployment • Determine placement • Configure sensor • Place sensor on network • Upload latest signatures • Test sensor for a period of time • Place sensor in production • Continue to patch and update signatures
Network Intrusion Detection • Other NIDS components • NIDS manager • NIDS database • NIDS console
Host Intrusion Detection • Sensors • Software application • Commercial vendors: Cisco, Enterasys, ISS, Tripwire, Symantec • Freeware: Tripwire, LIDS
Host Intrusion Detection • Placement • Use on critical systems • Watch resource utilization • Deploy infrastructure where sensor software can be easily updated
Host Intrusion Detection • Deployment • Install HIDS software • Configure HIDS software • Test software for a period of time • Place sensor in production • Continue to patch and update signatures
Honeypots • Various flavors: • Secure system that alerts whenever security controls are bypassed • Insecure systems that alerts whenever activity takes place • Emulates another OS • Modifies network communication to trap or slow down attackers
Analyzing IDS Monitoring and Responding to Events • Operator must determine if event is real threat: • Understand network or system “personality” • Correlate events • Bring in analyst for further investigation • Hand-off to incident management team
Summary • Network IDS provides the first layer in detective defenses by monitoring network activity. • Host IDS and honeypots offer a second layer of defenses in monitoring the activity on the systems themselves. • Data collection and analysis provide another layer to help organizations determine trending of attacks. • Finally, current news provides organizations with critical information on newly discovered attacks.
Summary • Intrusion detection systems can record malicious activity, distract attackers from real targets, and stall would-be attackers to buy response time. • The single biggest problem with IDS technologies is the false positives generated. • Using filtering, summarization, and rule modification, organizations can effectively lessen the number of false positives received. • NIDS sensors are an essential part of intrusion detection because they can view all traffic on a particular network segment.
Summary • HIDS sensors are useful for detecting attacks against a specific computer. • Honeypots are extremely flexible and useful in watching attackers in action. Additionally, honeypots can distract attackers away from real data targets. • Proper monitoring is comprised of two components of equal importance: intrusion detection devices and operators who are trained to analyze and respond to events.