What is an IDS?
IDS stands for "Intrusion Detection System." It is a device or application used to inspect all network traffic and alert the user or administrator to unauthorized attempts or access.
Unlike a firewall, which sits on the perimeter and acts as a gatekeeper to monitor network traffic and determine whether access to the network or endpoint should be allowed, an IDS focuses on internal network traffic to identify any suspicious or malicious activity. In this way, an IDS can detect attacks that manage to evade the firewall and those that come from within the network.
Most IDS solutions use a combination of signature-based detection, which compares traffic against a database of known attacks or attack techniques, and anomaly-based detection, which simply looks for suspicious activity or behavior that is strange or varies significantly from the established norm for detecting threats.
Why are network IDSs needed?
No firewall is foolproof and no network is impenetrable. Attackers are constantly developing new attack techniques to bypass defenses. Many attacks exploit other malware or social engineering to obtain user credentials that allow them to access the network and data. A network intrusion detection system is critical to network security because it allows malicious traffic to be detected and responded to.
The main benefit of an intrusion detection system is to ensure that IT personnel are alerted when an attack or intrusion into the network is in progress. A network intrusion detection system monitors incoming and outgoing traffic on the network, as well as data passing between systems within the network. The network IDS monitors network traffic and triggers alerts when suspicious activity or known threats are detected so that IT staff can take a closer look and take appropriate action to block or stop an attack.