IDS/IPS

4.1 Map the provided events to source technologies

📘Cisco Certified CyberOps Associate (200-201 CBROPS)


1. What is IDS and IPS?

  • IDS (Intrusion Detection System):
    • This system monitors network or system traffic and detects suspicious activity.
    • It does not block attacks automatically. It just alerts the security team.
    • Think of it as a security camera for your network—it notices suspicious behavior but doesn’t physically stop anything.
  • IPS (Intrusion Prevention System):
    • IPS does everything an IDS does, but it can also block or prevent attacks automatically.
    • It acts like a network guard that can stop malicious traffic before it reaches the target system.

2. Types of IDS/IPS

  1. Network-based IDS/IPS (NIDS/NIPS):
    • Monitors network traffic on switches, routers, and firewalls.
    • Example technologies: Snort, Suricata, Cisco Firepower.
    • Detects attacks like:
      • Port scanning
      • Malware communication
      • DDoS attacks
  2. Host-based IDS/IPS (HIDS/HIPS):
    • Runs on individual servers or endpoints.
    • Monitors files, logs, system calls, and user activity.
    • Example technologies: OSSEC, Tripwire.
    • Detects attacks like:
      • Unauthorized file changes
      • Privilege escalation
      • Malware execution

3. How IDS/IPS works

IDS/IPS use signatures and anomaly detection methods:

  1. Signature-based detection:
    • Looks for known patterns of attacks.
    • Works like antivirus software.
    • Example: Detecting a specific malware payload or SQL injection pattern.
  2. Anomaly-based detection:
    • Learns what normal traffic looks like, then alerts when traffic deviates from the norm.
    • Example: If a server suddenly starts sending huge amounts of data, it could indicate data exfiltration.

4. Events Generated by IDS/IPS

When an IDS/IPS detects something suspicious, it generates events. Knowing these events helps map them to source technologies for exam purposes.

Common IDS/IPS events:

Event TypeDescription
Port scan detectedSomeone is scanning your network for open ports.
Malware signature detectedKnown malware has been found in network traffic or a file.
Brute force login attemptMultiple failed login attempts detected on a server.
Policy violationTraffic violates security rules (e.g., blocked protocol).
Suspicious packet anomalyUnusual traffic patterns detected (possible attack).

5. IDS vs IPS in Event Handling

  • IDS events:
    • Alert only (logs, notifications)
    • Example: “Suspicious TCP connection detected from IP 192.168.1.50”
  • IPS events:
    • Alert and take action (block, drop, reset connection)
    • Example: “Connection from 192.168.1.50 blocked due to known SQL injection pattern”

6. Why IDS/IPS is important in CyberOps

  • Helps detect attacks quickly and minimize damage.
  • Provides visibility into network traffic and endpoint behavior.
  • Supports incident response by giving logs and alerts for security analysts.
  • Maps events to specific technologies so analysts know where the attack came from.

7. Example Scenario in IT Terms (No Cars or Analogies)

Imagine you have a web server:

  1. NIDS monitors traffic coming to the web server. It detects a SQL injection attempt.
    • IDS generates an alert: “SQL injection detected from IP 10.0.0.5”
    • Security team investigates.
  2. If you have NIPS active:
    • IPS detects the same attack
    • Automatically blocks traffic from 10.0.0.5
    • Event logged: “Traffic blocked: SQL injection from IP 10.0.0.5”

This shows how IDS alerts vs IPS prevents attacks.


8. Key Points to Remember for the Exam

  • IDS detects attacks → logs & alerts only.
  • IPS detects and prevents attacks → blocks malicious traffic.
  • Types: Network-based (monitors traffic) and Host-based (monitors system activity).
  • Detection methods: Signature-based (known patterns) and Anomaly-based (behavior deviations).
  • Events help map attacks to IDS/IPS technology, which is critical for exam questions.
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