Chapter 9 Configuring Anomaly Detection

Configuring Learning Accept Mode

Note Learning accept mode uses the sensor local time.

The scanner threshold defines the maximum number of zone IP addresses that a single source IP address can scan. The histogram threshold defines the maximum number of source IP addresses that can scan more than the specified numbers of zone IP addresses.

Anomaly detection identifies a worm attack when there is a deviation from the histogram that it has learned when no attack was in progress (that is, when the number of source IP addresses that concurrently scan more than the defined zone destination IP address is exceeded). For example, if the scanning threshold is 300 and the histogram for port 445, if anomaly detection identifies a scanner that scans 350 zone destination IP addresses, it produces an action indicating that a mass scanner was detected. However, this scanner does not yet verify that a worm attack is in progress. Table 9-2describes this example.

Table 9-2

Example Histogram

 

 

 

 

 

 

 

Number of source IP addresses

10

5

2

 

 

 

 

Number of destination IP addresses

5

20

100

 

 

 

 

 

When anomaly detection identifies six concurrent source IP addresses that scan more than 20 zone destination IP addresses on port 445, it produces an action with an unspecified source IP address that indicates anomaly detection has identified a worm attack on port 445. The dynamic filter threshold, 20, specifies the new internal scanning threshold and causes anomaly detection to lower the threshold definition of a scanner so that anomaly detection produces additional dynamic filters for each source IP address that scans more than the new scanning threshold (20).

You can override what the KB learned per anomaly detection policy and per zone. If you understand your network traffic, you may want to use overrides to limit false positives.

Triggering the High Category Histogram Before the Single-Scanner Threshold

Based on the default histogram (nonlearned knowledge base [KB]) values, histogram-based detection can occur before single-scanner detection.

Single scanner detection is based on the scanner threshold settings. The scanner threshold setting is a single number for that port or protocol and zone. Any single IP address scanning more than that number of hosts of that port or protocol in that zone is alerted as a scanner.

There is a histogram for that port or protocol and zone that tracks how many systems normally scan a smaller number of hosts (10 hosts, 20 hosts, or 100 hosts). When more than that normal number of scanners are seen, then a worm is declared and all IPs scanning more than the associated number of hosts are alerted on as being a worm scanner.

Note An IP source address can be alerted on as being a worm scanner without ever reaching the scanner threshold. The scanner threshold is used to detect single systems scanning a large number of hosts and is tracked separately from the algorithms for detecting worms.

 

 

Cisco Intrusion Prevention System Sensor CLI Configuration Guide for IPS 7.2

 

 

 

 

 

 

OL-29168-01

 

 

9-37

 

 

 

 

 

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Cisco Systems IPS4510K9 manual Example Histogram
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IPS4510K9 specifications

Cisco Systems has long been a leading player in network security, and its IPS (Intrusion Prevention System) series is a testament to its commitment to safeguarding digital environments. Among its notable offerings are the IPS4510K9 and IPS4520K9 models, both designed to provide advanced threat protection for mid-sized to large enterprise networks.

The Cisco IPS4510K9 and IPS4520K9 are distinguished by their cutting-edge features that help organizations defend against a myriad of cyber threats. These systems utilize a multi-layered approach to security, integrating intrusion prevention, advanced malware protection, and comprehensive visibility across the network.

One of the primary characteristics of the IPS4510K9 is its high performance. It boasts a throughput of up to 1 Gbps, making it suitable for environments that demand rapid data processing and real-time responses to threats. The IPS4520K9, on the other hand, enhances that capability with improved throughput of up to 2 Gbps, accommodating larger enterprises with heavier network traffic. These models are equipped with powerful processors that support complex signature matching and can intelligently distinguish between legitimate traffic and potential threats.

In addition to performance, both models are designed with scalability in mind. They can be easily integrated into existing Cisco infrastructures. This facilitates a seamless enhancement of security without causing significant interruptions to ongoing operations. Moreover, they offer flexible deployment options, allowing organizations to operate them inline or out of band depending on their specific needs.

The Cisco IPS4510K9 and IPS4520K9 leverage advanced detection technologies, utilizing a variety of signature types and heuristic analysis to detect known and unknown threats effectively. They are equipped with real-time alerting and reporting capabilities, giving security teams immediate visibility into potential breaches and enabling them to respond swiftly.

Furthermore, both models support a range of management options through the Cisco Security Manager, allowing for centralized administration, streamlined policy management, and enhanced monitoring capabilities. Automated updates ensure the systems remain current with the latest threat intelligence, vital for staying ahead of evolving cyber threats.

In summary, the Cisco Systems IPS4510K9 and IPS4520K9 represent powerful solutions for organizations seeking robust intrusion prevention capabilities. With their high performance, scalability, and advanced detection technologies, these systems are essential tools in the ever-changing landscape of cybersecurity, providing enterprises with the peace of mind needed to operate securely in today's digital world.
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