Organizations continue to face an ever-growing number of cybersecurity threats. As threats become more sophisticated and advanced, it is critical to protect the network and sensitive data. Two tools that can aid in safeguarding your network and data are an Intrusion Detection System (IDS) and an Intrusion Prevention System (IPS). They both play important roles in identifying and mitigating threats, but function in unique ways. This blog will explore the similarities and differences between an IDS and an IPS and how they can impact the security of your environment.
Defining an IDS
Imagine you have visibility into a busy network, where lots of network traffic of packets and activity come and go all day long. The IDS continuously inspects and monitors the network during all hours. The IDS monitors traffic and looks for unusual patterns or anomalies, such as users accessing infrequently access or inaccurate files or if the names/signatures of packets are on a watch list. If it sees suspicious activity it will alert the administrators to investigate further. The IDS doesn’t stop any of the traffic, it monitors activity and alerts the proper channels as needed.
An IDS uses pattern analysis to detect attacks, port scanning (which can be used to identify open or vulnerable services), and anomalous behavior on the network. A signature-based IDS can detect known malware, viruses, and known software vulnerabilities. The IDS can alert when policies, such as restricted file access, are being modified. Additionally, prior to someone attacking your network, they may probe and map it. An IDS can detect these types of events as well.
Data Collection, Alerting, Logging, & Resolution
Once the IDS is configured, it can begin collecting data from sources including network traffic and system logs. There are two types of IDS in relation to the collection of data: network-based IDS (NIDS), which monitors the traffic that is flowing throughout the network, and host-based IDS (HIDS), which monitors logs, files, and processes on the host system.
As the IDS detects known or potential threats, it will generate an alert to notify the administrator of the tool. The IDS tool will also log any additional investigation around the event. If events have occurred that require manual follow-up, a vulnerability and threat management policy can assist personnel in mitigating and remediating threats in a consistent manner.
How an IPS is Different Than an IDS
As the IDS detects known or potential threats, it will generate an alert to notify the administrator of the tool. The IDS tool will also log any additional investigation around the event. If events have occurred that require manual follow-up, a vulnerability and threat management policy can assist personnel in mitigating and remediating threats in a consistent manner.
Going back to our visibility into a network, for example, if the tool being utilized was an IPS, it would monitor files, packets, and activity and assess any anomalies, but it can also prevent access or quarantine files by itself.
An IPS goes a step further than an IDS in that it can perform actions to stop threats in real time. Similar to an IDS, the IPS can also continue to log the events that occurred and alert administrators. While monitoring and analyzing network traffic an IPS can take the following responses, for example:
- Slow traffic to reduce the load on the network and its resources.
- Block connections to stop an attacker from reaching the intended target.
- Terminate network connections that are involved in an attack.
- Sync with other tools, such as a firewall, to block IP addresses or update policies.
How an IPS Stays Up-to-Date
- The IPS vendor will maintain and update a database of known attack signatures. This includes, but is not limited to, signatures for malware and viruses.
- An IPS can be integrated with threat intelligence feeds. By subscribing to these feeds it can allow the IPS to recognize emerging concerns prior to a signature for the threat being released.
- Pattern recognition and behavior analysis can continuously evolve as more data is analyzed.
- As with any tool, the IPS should receive patches and rule updates as they become available. Maintaining the patches and updates on your IPS helps it maintain its performance and function.
Benefits & Pitfalls of IDS, IPS, & IDPS
These tools provide real-time threat detection that allows you to have greater insight into your environment. They aid in strengthening an entity’s security posture and can assist in meeting requirements for compliance regulations. When incidents occur, the tools are beneficial in the investigation by retaining event and activity logs. While they can detect threats earlier, the IPS goes a step further by reducing downtime through automated mitigation. You can also combine these tools, also known as an IDPS (intrusion detection and prevention system).
While there are many benefits to utilizing an IDS or IPS in your environment, there can also be downsides. These tools can cause false alerts and alert fatigue if the policies are not accurately defined. If your environment operates with inherent inconsistencies, such as a high frequency of changes in activities, these may generate false alerts as well. Alerts from an IDS may still require a human element to review, investigate, and remediate threats. Additionally, if an IPS is monitoring all traffic, it can slow down network performance.
Firewall vs. IDS vs. IPS
A firewall is a network device that restricts incoming and outgoing traffic based on predefined rules. It can also restrict users within the network from accessing forbidden websites. It will not analyze traffic, detect threats, or initiate alerts. An IDS does not restrict traffic like a firewall, but it does analyze, detect, and alert administrators to potential threats and patterns regarding the traffic. An IPS is different from a firewall and IDS in the sense that it monitors traffic but will then take action against threats.
A firewall is usually placed at the perimeter of a network, in order to filter the incoming and outgoing traffic. An IDS is placed inside the network to monitor traffic, while an IPS is implemented in line with traffic, as this allows the traffic to pass through it.
Final Thoughts on Intrusion Detection & Prevention Systems
An IDS and IPS are components to be considered for modern network security. Together, these systems complement each other – an IDS provides detailed insights and an IPS enforces real-time protection. Understanding the functions, strengths, and limitations of each tool is important for implementing a security strategy that can effectively safeguard networks and meet the businesses’ needs.
If you have questions for the team at Linford & Co. about how these tools can impact your environment and how they can be used to meet your compliance needs, please contact us and request a consultation.
Hilary has eight years of IT audit and assurance experience. Prior to starting at Linford & Co, Hilary worked for Deloitte managing audit readiness assessments, Sarbanes-Oxley 404 and SOC examinations, and complex remediation procedures. Hilary is a certified information systems auditor (CISA), holds a Master’s Degree in Accounting from the University of Colorado-Denver and a Bachelor’s in Business Administration from Colorado State University.