PR #229

d3fend.ttl

:NetworkSignatureAnalysis a :NetworkTrafficAnalysis,
        owl:Class,
        owl:NamedIndividual ;
    rdfs:label "Network Signature Analysis" ;

    rdfs:subClassOf :NetworkTrafficAnalysis,
        [ a owl:Restriction ;
            owl:onProperty :analyzes ;
            owl:someValuesFrom :NetworkTraffic ] ;
    :d3fend-id "D3-NSA" ;
    :definition "Analyzing network traffic and compares it to known signatures" ;
    :kb-article """## How it works

Network signature analysis relies on predefined patterns, or signatures, to identify malicious network activity. These signatures typically match against specific byte sequences, packet header information, or protocol anomalies indicative of known threats.

The process works as follows:

* Packet Capture: Network traffic is captured on an interface or port, resulting in a stream of raw packets.
* Preprocessing: The captured packets are preprocessed, cleaning and normalizing the data for efficient analysis.
* Signature Matching: Each packet is compared against a database of signatures using dedicated engines.

## Considerations

### False Negatives

Network signature analysis is susceptible to generating false negatives. These occur when malicious activity evades detection due to limitations in the signature-based approach. Here are some common causes:

* Evolving threats: Attackers frequently modify their tactics, rendering existing signatures ineffective against new variants.
* Obfuscation: Attackers may disguise malicious content using encryption, encoding, or other techniques to bypass signature detection.
* Limited visibility: Signatures rely on specific patterns. If crucial information is encrypted or hidden, the signature might miss the threat.
* Zero-day attacks: By definition, new and unknown attacks lack corresponding signatures, allowing them to pass undetected.

### False Positives

Network signature analysis is susceptible to generating false positives. These occur when the signature analysis triggers an alert for benign traffic. Common causes include:

* Overly broad signatures: Rules designed to be too general might match harmless activities, generating false alarms.
* Network misconfigurations: Improperly configured devices or legitimate network activity can mimic malicious patterns, triggering false positives.
* Data errors: Corrupted or incomplete network data can lead to misinterpretations and false alerts.

""" 
:kb-article """## References
Signature-based. (2024, April 22). In _Wikipedia_  [Link](https://en.wikipedia.org/wiki/Intrusion_detection_system#Signature-based)""" .