Chapter 7 Defining Signatures

Creating Custom Signatures

Meta Signature Engine Enhancement

The purpose of the Meta engine is to detect a specified payload from an attacker and a corresponding payload from the victim. It is also used to inspect streams at different offsets. The Meta engine supports the AND and OR logical operators. ANDNOT capability has been added to the Meta engine. This clause is a negative clause used to complement the existing positive clause-based signatures. The previous signature format had the following form:

IF (A and B and C) then Alarm; alternatively, IF (A or B or C) then Alarm is also supported; where A, B, and C are meta component signatures.

The addition of the negative clause allows for the following logic:

IF (A and/or B) AND NOT (C and/or D) then Alarm.

The (C and/or D) is the negative clause and is satisfied if (C and D) [alternatively (C or D)] do not occur before the Meta Reset Interval time expires.

A component of the positive clause must occur before the negative clause(s) to establish the Meta tracking state. The Meta engine cannot track the lack of past behavior. The state of the negative clause is evaluated when the Meta Reset Interval time expires.

Caution A custom signature can affect the performance of your sensor. Test the custom signature against a baseline sensor performance for your network to determine the overall impact of the signature.

The Meta engine is different from other engines in that it takes alerts as input where most engines take packets as input.

The following options apply:

•component-listname1—Specifies the list of Meta components:

–edit—Edits an existing entry in the list.

–insert —Inserts a new entry into the list.

–move—Moves an entry in the list.

–begin—Places the entry at the beginning of the active list.

–end—Places the entry at the end of the active list.

–inactive—Places the entry into the inactive list.

–before—Places the entry before the specified entry.

–after—Places the entry after the specified entry.

–component-count—Specifies the number of times component must fire before this component is satisfied.

–component-sig-id—Specifies the signature ID of the signature to match this component on.

–component-subsig-id—Specifies the subsignature ID of the signature to match this component on.

–is-not-component {true false}—Specifies that the component is a NOT component.

•component-list-in-order {true false}—Specifies whether to have the component list fire in order. For example, if signature 1001 in the m2 component fires before signature 1000 in the m1 component, the Meta signature will not fire.

•all-components-required {true false}—Specifies to use all components. This option works with the all-not-components-requiredoption, if you have NOT components configured as required, the Meta signature will not fire.

 

 

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Cisco Systems IPS4510K9 manual Meta Signature Engine Enhancement
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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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