______________________________________________________________________________ What is an Intrusion Detection System?  A system called an Intrusion Detection System (IDS) observes network traffic for malicious transactions and sends immediate alerts when it is observed.  It is software that checks a network or system for malicious activities or policy violations.  Each illegal activity or violation is often recorded either centrally using an SIEM (Security information and event management) system or notified to an administration.  IDS protects a computer network from unauthorized access from users, including perhaps insiders.  It uses machine learning techniques such a predictive model (i.e. a classifier) capable of distinguishing between ‘bad connections’ (intrusion/attacks) and ‘good (normal) connections’. Working of Intrusion Detection System  An IDS (Intrusion Detection System) monitors the traffic on a computer network to detect any suspicious activity.  It analyzes the data flowing through the network to look for patterns and signs of abnormal behavior.  The IDS compares the network activity to a set of predefined rules and patterns to identify any activity that might indicate an attack or intrusion.  If the IDS detects something that matches one of these rules or patterns, it sends an alert to the system administrator.  The system administrator can then investigate the alert and take action to prevent any damage or further intrusion. Classification of Intrusion Detection System Intrusion Detection System are classified into 5 types: 1. Network Intrusion Detection System (NIDS): It examines traffic from all devices on the network. It performs an observation of passing traffic on the entire subnet and matches the collection of known attacks. Once an attack is identified or abnormal behavior is observed, the alert can be sent to the administrator.  An example of a NIDS is installing it on the subnet where firewalls are located in order to see if someone is trying to crack the firewall. 2. Host Intrusion Detection System (HIDS): It runs on independent hosts or devices on the network. A HIDS monitors the incoming and outgoing packets from the device only and will alert the administrator if suspicious or malicious activity is detected. It takes a snapshot of existing system files and compares it with the previous snapshot. If the analytical system files were edited or deleted, an alert is sent to the administrator to investigate. What is an Intrusion Detection System?  Working of Intrusion Detection System  Classification of Intrusion Detection System  Intrusion Detection System Evasion Techniques  Benefits of IDS ______________________________________________________________________________ What is an Intrusion Detection System?  A system called an Intrusion Detection System (IDS) observes network traffic for malicious transactions and sends immediate alerts when it is observed.  It is software that checks a network or system for malicious activities or policy violations.  Each illegal activity or violation is often recorded either centrally using an SIEM (Security information and event management) system or notified to an administration.  IDS protects a computer network from unauthorized access from users, including perhaps insiders.  It uses machine learning techniques such a predictive model (i.e. a classifier) capable of distinguishing between ‘bad connections’ (intrusion/attacks) and ‘good (normal) connections’. Working of Intrusion Detection System  An IDS (Intrusion Detection System) monitors the traffic on a computer network to detect any suspicious activity.  It analyzes the data flowing through the network to look for patterns and signs of abnormal behavior.  The IDS compares the network activity to a set of predefined rules and patterns to identify any activity that might indicate an attack or intrusion.  If the IDS detects something that matches one of these rules or patterns, it sends an alert to the system administrator.  The system administrator can then investigate the alert and take action to prevent any damage or further intrusion. Classification of Intrusion Detection System Intrusion Detection System are classified into 5 types: 1. Network Intrusion Detection System (NIDS): It examines traffic from all devices on the network. It performs an observation of passing traffic on the entire subnet and matches the collection of known attacks. Once an attack is identified or abnormal behavior is observed, the alert can be sent to the administrator.  An example of a NIDS is installing it on the subnet where firewalls are located in order to see if someone is trying to crack the firewall. 2. Host Intrusion Detection System (HIDS): It runs on independent hosts or devices on the network. A HIDS monitors the incoming and outgoing packets from the device only and will alert the administrator