Idp Signature Groups - D-Link NetDefendOS User Manual

• Intrusion Protection Signatures (IPS)
These are highly accurate and a match is almost certainly an indicator of a threat. Using the
Protect action is recommended. These signatures can detect administrative actions and
security scanners.
• Intrusion Detection Signatures (IDS)
These can detect events that may be intrusions. They have lower accuracy than IPS and may
give some false positives so it is recommended that the Audit action is always used. Using
them with Protect may interrupt normal traffic.
• Policy Signatures
These detect different types of application traffic. They can be used to block certain
applications such as file sharing applications and instant messaging.

6.6.6. IDP Signature Groups

Using Groups
Usually, several lines of attacks exist for a specific protocol, and it is best to search for all of them
at the same time when analyzing network traffic. To do this, signatures related to a particular
protocol are grouped together. For example, all signatures that refer to the FTP protocol form a
group. It is best to specify a group that relates to the traffic being searched than be concerned
about individual signatures. For performance purposes, the aim should be to have NetDefendOS
search data using the least possible number of signatures.
Specifying Signature Groups
IDP Signature Groups fall into a three level hierarchical structure. The top level of this hierarchy is
the signature Type, the second level the Category and the third level the Sub-Category. The
signature group called POLICY_DB_MSSQL illustrates this principle where Policy is the Type, DB
is the Category and MSSQL is the Sub-Category. These 3 signature components are explained
below:
1. Signature Group Type
The group type is one of the values IDS, IPS or Policy. These types are explained above.
2. Signature Group Category
This second level of naming describes the type of application or protocol. Examples are:
• BACKUP
• DB
• DNS
• FTP
• HTTP
3. Signature Group Sub-Category
The third level of naming further specifies the target of the group and often specifies the
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Chapter 6: Security Mechanisms