GP.Access Security

	GP	Access Security	Version:	0.3
	Document type:	Generic Pattern	Owner:	J.A.H. Schoonderbeek

Description

This Generic Pattern belongs to "Business Support". An implementation of this Pattern can be used to secure access to back-end resources. By and large, it performs either or both of the following two tasks:

It can use the combination of Connection Handling and Filter function to deny traffic to pass to the back-end resource, until proper authentication and authorization have occurred, so as to shield the protected resources against unauthorized access;
It can use the combination of Data Scanning and a Filter function, to shield the protected resources from malicious or malformed traffic.

If needed, Encryption functionality can secure the communication between the consumers of the back-end resource and the Access Security pattern itself, and/or between the Access Security pattern and the back-end resource itself. Note that for many security operations, the traffic between consumers and back-end resources need to be unencrypted, so as to allow inspection by this Generic Pattern.

Furthermore, Reduction may be used to allow compression of the data traffic between consumers and the Access Security service, for efficient data transfers. Note that for many security operations, the traffic between consumers and back-end resources need to be uncompressed, so as to allow inspection by this Generic Pattern.

This service is often combined with Access Distribution; such a combination may be realized as an "access path".

Services realized

This Pattern realizes the following service(s):

Access Security (This service is used to secure access to back-end resources.)

Functional and Integration view

This is the graphic representation of the functional model of this Generic Pattern:

Generic Pattern Composition

This pattern is an aggregation of the following (mandatory and optional) functions, expressed in Generic Functions:

Icon	Function	Inclusion	Rationale
	Filtering	recommended	This function delivers the Pattern's core functionality, as it provides the pattern with a means to reduce the attack surface of a protected back-end resource, by filtering data traffic towards and from the protected resource. Note that when filtering is required on more than just traffic characteristics, then decryption and/or decompression of the data traffic under consideration may require the Filtering functionality to use Session Handling functionality to access the data transported.
	Data Scanning	optional	This function provides extra capability to the Filtering function, by allowing for scanning of the data transported. This enables Filtering to filter traffic on data characteristics.
	Connection Handling	recommended	This function terminates a consumer's connection to the protected resource, and sets up its own session to that resource. This provides the Access Security pattern with the following security-related abilities: can access the content of encrypted sessions (e.g. SSL sessions) for inspection purposes; can gracefully filter types of session requests/answers that are malformed or deemed inappropriate for the particular protected facility (e.g. HTTP POST).
	Encryption	optional	Inclusion of this function allows encrypted communication between the consumer and this pattern (necessary for private communication), even when the protected back-end resource itself may not be able to do this. On the other hand, it allows for decrypting encrypted traffic from the consumer for inspection purposes, before the traffic reaches the protected resource (and vice versa).
	Reduction	optional	Allows compressed communication between the consumer and this pattern (advisable for efficient data transfer), even when the protected resource may not be able to do this. On the other hand, allows for decompressing compressed traffic from the consumer for inspection purposes, before the traffic reaches the protected resource (and vice versa).
	Controlling	recommended	Access to the configuration and operation of this Pattern is most always restricted. Furthermore, special care is required to ensure sufficient access to the configuration and operation whenever a security incident occurs: e.g. when a back-end resource is being attacked, Security personnel must be able to check and adapt the configuration of Access Security while the attack is underway.

Services connected with this Generic Pattern

This Generic Pattern has the following mandatory and optional relations with adjacent Generic Services.

Service	Adjacency	Summary	Rationale
Data Transport	recommended	This service transports data between automated systems.	While virtually all Generic Patterns have a relation with Data Transport, this relation is more noteworthy for Access Security, since the designer will have to fit Access Security correctly between a Data Transport instance and the IT resource for which it is securing access. The presence of (one or more instances of) Data Transport service serves to model all concerns relating to the correct fit.
Authentication & Authorization	optional	This service can validate an identity claim, and it can validate the permissions required for an action, as part of an Authentication & Authorization process.	The Authentication & Authorization service can be used to authenticate consumers for the protected back-end resource (usually at the location where Session Handling takes place) and/or to authorize access to the protected back-end resource . Authorization can also take place based on traffic characteristics, data characteristics and/or other conditions. The effect can be that consumers are denied access to the back-end resource based on many criteria, such as: multiple failed authentication attempts; denial of Service traffic patterns; blacklisting of consumers based on characteristics such as network address or machine name; suspect behaviour such as incorrect reverse lookups or incorrect or incomplete answers to challenges; absence of up-to-date antivirus at the consumer machine. These criteria can be managed within the Access Security implementation itself, but they may just as well be managed using a separate Authorization service.
Facilities Monitoring	optional	This service allows its users to monitor IT facilities with the aim of guarding operational continuity or security.	Access Security is usually employed to secure access to the IT resource that this Pattern is protecting. Thus, many events that occur in an Access Security facility are of interest to Security staff. This means it is desirable to have the facility report directly to (a Security instance of) Facilities Monitoring.

Applied Patterns based on this Generic Pattern

The following Applied Patterns are based wholly or in part on this Generic Pattern: