What are the characteristics of network-based IDS?

Network-based Intrusion Detection Systems (NIDS) monitor and analyze network traffic for suspicious or malicious activity. Key characteristics include:

1. Passive Monitoring: NIDS typically operates in promiscuous mode, sniffing network traffic without interfering with data flow. It detects threats by analyzing packet headers and payloads.
   Example: A NIDS can identify port scans or unusual traffic patterns, such as a sudden spike in DNS requests, indicating potential malware communication.

2. Network-Wide Visibility: Unlike host-based IDS, NIDS monitors traffic across the entire network segment, providing a broader perspective on potential threats.
   Example: It can detect lateral movement within a network, such as an attacker pivoting from one compromised host to another.

3. Signature-Based and Anomaly-Based Detection:

   • Signature-Based: Matches traffic against known attack patterns (e.g., SQL injection attempts).
   • Anomaly-Based: Detects deviations from normal network behavior, such as unusual data transfer volumes.
     Example: A NIDS using anomaly detection might flag a host suddenly sending large amounts of data to an external IP, suggesting data exfiltration.

4. Real-Time Alerting: NIDS generates alerts when suspicious activity is detected, enabling rapid response.
   Example: If a NIDS detects a brute-force attack on an SSH server, it can immediately notify administrators.

For scalable and reliable network monitoring, Tencent Cloud offers Host Security (CWP) and Network Security (T-Sec Network Security) services, which include advanced threat detection and response capabilities. These services integrate seamlessly with Tencent Cloud’s infrastructure to safeguard networks from evolving threats.