Intrusion Prevention System (IPS)


An intrusion prevention system (IPS) is a security appliance or software that combines detection capabilities with functions that can actively block attacks.

  • provides an active response to any network threats that it matches
  • preventative measures:
    • end the session by sending a TCP reset packet to the attacking host
    • apply a temporary/permanent filter on the firewall to block the attacker’s IP address
      • called shunning
    • advanced measures:
      • throttling bandwidth to attacking hosts
      • applying complex firewall filters
      • modifying suspect packets to render them harmless
      • redirect traffic to honeypot or honeynet
  • may be able to run a script or third-party program
    • to perform some other action not supported by the IPS software itself
  • commonly built into firewall appliances and proxy servers
  • IPS-enabled firewall is inline with the network
    • means all traffic passes through it
      • single point of failure if there is no fault tolerance mechanism
  • must be able to:
    • handle with high bandwidths
    • process each packet very quickly to avoid slowing down the network

Types

Detection Types

Tools

  • Snort
    • uses a rule-driven language, which combines the benefits of signature, protocol, and anomaly-based inspection methods, providing robust detection capabilities
    • open-source
  • Suricata
    • high-performance open source IDS/IPS/NSM engine
    • designed to take full advantage of modern hardware
    • deliver higher performance and scalability than Snort
    • can function as an IDS or an IPS
    • compatible with Snort rulesets
  • Security Onion
    • is a Linux distribution designed for intrusion detection, network security monitoring, and log management
    • includes many tools to provide a complete platform for network security
      • Snort
      • Suricata
      • along with a host of other tools
    • provides a holistic view of network activity
    • enables correlating data from different tools to obtain a comprehensive understanding of the network’s security posture