What Is an Intrusion Detection System? Intrusion detection systems (IDSes) analyze network traffic for signatures of known attackers. The systems can be hardware devices or software solutions. An IDS can mitigate existing malware, such as backdoors, rootkits, and trojans.
The goal of an intrusion detection system is to detect an attack as it occurs. The system starts by analyzing inbound and outbound network traffic for signs of known attackers.
Some activities an IDS performs include:
When the system detects an anomaly, such as a virus, a configuration error, or a security policy violation, it sends an alert to IT security. The IDS can stop an ongoing attack by kicking the intruder off the network.
The downside of intrusion detection systems is that they only work with known attack signatures. Thus, they cannot detect zero-day threats and incoming attacks.
The goal of an intrusion detection system is to detect an attack as it occurs. The system starts by analyzing inbound and outbound network traffic for signs of known attackers.
Some activities an IDS performs include:
When the system detects an anomaly, such as a virus, a configuration error, or a security policy violation, it sends an alert to IT security. The IDS can stop an ongoing attack by kicking the intruder off the network.
The downside of intrusion detection systems is that they only work with known attack signatures. Thus, they cannot detect zero-day threats and incoming attacks.
There are various types of intrusion detection system types that differ according to what part of the network they monitor or whether they are software or hardware devices.
The most common types include:
Network-based Intrusion Detection System (NIDS)
A NIDS is a software solution that operates at the network level, monitoring inbound and outbound traffic from all devices on the network. The system analyzes the traffic, looking for signs and patterns of malicious activity. If it finds an anomaly, it sends an alert.
Host-based Intrusion Detection System (HIDS)
A HIDS monitors the system data of an individual host instead of the entire network. The system looks for anomalies and malicious activity in the operating system files and software. When it finds an anomaly, it sends an alert and can take a snapshot to check if there is a suspicious change in activity.
Application-Protocol Intrusion Detection System (APIDS)
An APIDS is a type of HIDS that monitors and analyzes a specific application protocol. The system monitors the application protocol’s dynamic behavior and state, typically monitoring the interactions between two connected devices. When it detects suspicious behavior, the system raises an alert.
Other types of intrusion detection systems include:
Intrusion prevention systems (IPSes) are software solutions that monitor incoming traffic for malicious requests. An IPS can prevent attackers from delivering suspicious packets and block suspicious IPs. It uses signature recognition and recognizes attack patterns and anomalies.
How does an IPS work?
An IPS actively scans network traffic for known attack signatures and anomalies with the goal of preventing malicious traffic from entering the network. If the system determines that a packet is a threat, it drops the packet and blocks the IP address or port from future traffic.
Some activities an IPS performs include:
When a threat is confirmed, the IPS can use response techniques like resetting a connection, blocking traffic, and sending automated alarms. Some systems may configure firewalls and replace the attack contents with warnings.
What’s the difference between an IPS and a Firewall?
Many users would ask: Why do I need an IPS if I have a firewall? The two solutions work differently and an IPS can catch packets that slip through a firewall.
While an IPS monitors inbound traffic and packets and decides whether or not to let the packets into the network, a firewall blocks traffic based on port, protocol, or IP address information.
There are four types of IPS:
IDS |
IPS |
|
Monitors the network and detects ongoing attacks |
Controls the network and rejects incoming attacks |
|
Compares packets according to known threat signatures |
Compares packets according to known threat signatures |
|
Proactively looks for signs that an attack is in progress. |
Prevents incoming attacks by denying network traffic to suspicious packets. |
|
Mitigates threats within the network |
Blocks the threat before it gains access to the network |
The main difference between an IDS and an IPS is that an IDS offers a reactive approach, mitigating threats within the network, whereas an IPS focuses on preventing attackers from entering the network to begin with.
Can you use IDS and IPS together?
An IPS can complement the work of an IDS by detecting and blocking incoming attacks. Thus, IDS and IPS can work together to provide a more complete network security solution.
Cyber attacks are on the rise, and the financial impact of a security attack is increasingly costly. With the average cost of a data breach over $3.8 million in 2020, companies look for effective protection.
Almost every organization has a firewall, anti-malware, or endpoint protection tool. Yet, no protection method is perfect and some packets can sneak in past firewalls. Therefore, there is a need to complement the firewall’s limitations.
Also, these methods cannot do much once an attacker is inside the network.
Even with perfect firewall rules, you are going to let some packet in that you didn’t expect. Thus, once traffic comes to your network past a firewall, you need to track it to make sure it isn’t malicious.
Intrusion detection and intrusion prevention tools can solve these challenges.
