ArchiMate modelling language is one of the The Open Group enterprise architecture standards. It is aligned with TOGAF and aims to help architects (and other interested parties) understand the impact of design choices and changes.
Here I would like to build on the foundation we’ve laid while discussing SABSA architecture and design case study and share and example of using the Archi tool to model security architecture using the SABSA framework.
Let’s say ACME Corp asked us to help them with their security architecture. Where do we start?
As described in my previous blog, let’s establish Contextual Architecture.
Using Archi, I select Principles (can be found in Motivation section) for attributes and define composition relationship between elements (e.g. ACME Corp is composed of Cost-effective, Reputable and many other attributes that hopefully define the business).
Here and below I’ll be using a simplified example just to illustrate a point – you will have many more attributes in practice.
From reading company annual reports and talking to business stakeholders we can start identifying business drivers of ACME Corp. We can them map these business drivers to attributes. Below is an illustration of mapping a business driver Generate revenue (Driver element) to the attribute Cost-effective using Influence relation, as business drivers influence attributes.
On the Conceptual architecture level we need to start defining lower level attributes. For example, Cost-effective is composed (Composition relation) of Available and Business-driven
Remember that you can provide definitions of your attributes in the element’s properties (Main section). In this example I’m defining Available as Service should be uninterrupted. You are also encouraged to establish a measurement approach for each attribute. You can see above that Uptime is the main KPI for availability. It’s a hard measure where we monitor the percentage of time system is available compared to what is specified in the SLA.
Logical level provides an insight into what capabilities enable the attributes. In the example below, Available is realised (Realsisation relation) by Backup capability which in turn is comprised of Synchronous and Asynchronous backup capabilities (Composition relation).
Archi tool allows us to model SABSA Physical Architecture view by describing services, events, processes, interfaces, functions and other elements of the TOGAF Technology layer.
Below is a simplified example of describing the Asynchronous backup capability.
Asynchronous backup is being realised by Backup manager application service (reaalisation relation). Backup store is a data object that is being accessed by the Backup manager (access relation).
You can be quite detailed here and that’s where Archi tool can add a lot of value. But to keep things simple, I’m going to leave it at that. You can decompose elements into services and function, group them together and even go lower describing actual technology solutions on SABSA Component architecture level.
The real question is: what do you do with all of this?
My answer is simple: visualise.
Archi let’s you switch into the Visualiser mode and create graphs bringing all your hard work together. Playing with depth (6 in the example above) you can analyse the architecture and ensure traceability: you can see and, more importantly, demonstrate to your business stakeholders how a particular technology solution contributes to the overall business objective.
In addition, the Validator allows you to see the elements that are orphaned, i.e. not related to any other element. You then have the ability to rectify this and introduce a relationship or discontinue the capability (otherwise, why are you paying for something that is not in use?).
If you followed the steps above, the tool, despite being free, actually does a lot of the heavy lifting for you and automatically adjusts the models and graphs if changes to the architecture are introduced.
Now it’s your turn to try out Archi for SABSA architecture. Good luck!
I would like to thank Chul Choi for outlining the above technique.
Let’s talk about applying the SABSA framework to design an architecture that would solve a specific business problem. In this blog post I’ll be using a fictitious example of a public sector entity aiming to roll-out an accommodation booking service for tourists visiting the country.
To ensure that security meets the needs of the business we’re going to go through the layers of the SABSA architecture from top to bottom.
Start by reading your company’s business strategy, goals and values, have a look at the annual report. Getting the business level attributes from these documents should be straightforward. There’s no need to invent anything new – business stakeholders have already defined what’s important to them.
Every single word in these documents has been reviewed and changed potentially hundreds of times. Therefore, there’s usually a good level of buy-in on the vision. Simply use the same language for your business level attributes.
After analysing the strategy of my fictitious public sector client I’m going to settle for the following attributes: Stable, Respected, Trusted, Reputable, Sustainable, Competitive. Detailed definitions for these attributes are agreed with the business stakeholders.
Next step is to link these to the broader objectives for technology. Your CIO or CTO might be able to assist with these. In my example, the Technology department has already done the hard job of translating high-level business requirements into a set of IT objectives. Your task is just distill these into attributes:
Now it’s up to you to define security attributes based on the Technology and Infrastructure attributes above. The examples might be attributes like Available, Confidential, Access-Controlled and so on.
The next step would be to highlight or define relationships between attributes on each level:
These attributes show how security supports the business and allows for two-way tracebility of requirements. It can be used for risk management, assurance and architecture projects.
Back to our case study. Let’s consider a specific example of developing a hotel booking application for a public sector client we’ve started out with. To simplify the scenario, we will limit the application functionality requirements to the following list:
|P001||Register Accommodation||Enable the registration of temporary accommodations available|
|P002||Update Availability||Enable accommodation managers to update availability status|
|P003||Search Availability||Allow international travellers to search and identify available accommodation|
|P004||Book Accommodation||Allow international travellers to book accommodation|
|P005||Link to other departments||Allow international travellers to link to other departments and agencies such as the immigration or security services (re-direct)|
And here is how the process map would look like:
There are a number of stakeholders involved within the government serving international travellers’ requests. Tourists can access Immigration Services to get information on visa requirements and Security Services for safety advice. The application itself is owned by the Ministry of Tourism which acts as the “face” of this interaction and provides access to Tourist Board approved options. External accommodation (e.g. hotel chains) register and update their offers on the government’s website.
The infrastructure is outsourced to an external cloud service provider and there are mobile applications available, but these details are irrelevant for the current abstraction level.
From the Trust Modelling perspective, the relationship will look like this:
Subdomain policy is derived from, and compliant with, super domain but has specialised local interpretation authorised by super domain authority. The government bodies act as Policy Authorities (PA) owning the overall risk of the interaction.
At this stage we might want to re-visit some of the attributes we defined previously to potentially narrow them down to only the ones applicable to the process flows in scope. We will focus on making sure the transactions are trusted:
Let’s overlay applicable attributes over process flows to understand requirements for security:
Now it’s time to go down a level and step into more detailed Designer’s View. Remember requirement “P004 – Book Accommodation” I’ve mentioned above? Below is the information flow for this transaction. In most cases, someone else would’ve drawn these for you.
With security attributes applied (the direction of orange arrows define the expectation of a particular attribute being met):
These are the exact attributes we identified as relevant for this transaction on the business process map above. It’s ok if you uncover additional security attributes at this stage. If that’s the case, feel free to add them retrospectively to your business process map at the Conceptual Architecture level.
After the exercise above is completed for each interaction, it’s time to go down to the Physical Architecture level and define specific security services for each attribute for every transaction:
At the Component Architecture level, it’s important to define solution-specific mechanisms, components and activities for each security service above. Here is a simplified example for confidentiality and integrity protection for data at rest and in-transit:
|Service||Physical mechanism||Component brands, tools, products or technical standards||Service Management activities required to manage the solution through-life|
|Message confidentiality protection||Message encryption||IPSec VPN||Key management, Configuration Management, Change management|
|Stored data confidentiality protection||Data encryption||AES 256 Disk Encryption||Key management, Configuration Management, Change management|
|Message integrity protection||Checksum||SHA 256 Hash||Key management, Configuration Management, Change management|
|Stored data integrity protection||Checksum||SHA 256 Hash||Key management, Configuration Management, Change management|
As you can see, every specific security mechanism and component is now directly and traceable linked to business requirements. And that’s one of the ways you demonstrate the value of security using the SABSA framework.
Aligning OWASP Application Security Verification Standard and SABSA Architecture framework.
OWASP Application Security Verification Standard (Standard) is used at one of my clients to help develop and maintain secure applications. It has been used it as blueprint create a secure coding checklist specific to the organisation and applications used.
Below is an excerpt from the Standard related to the authentication verification requirements:
The Standard provides guidance on specific security requirements corresponding to the Physical layer of the SABSA architecture.
Organisations around the world are increasingly relying on third-party vendors to provide them with competitive advantage. Many companies in a race to optimise processes and reduce costs begin to outsource core functions. This leads to increased risk profile and new challenges of supplier oversight.
Dealing with third-parties has grown bigger than being just a procurement issue. Suppliers companies increasingly rely on, pose not only legal but also reputational risks that cannot be fully transferred. Security and privacy related incidents related to third-party providers are presenting new management challenges. Moreover, regulators are increasingly demanding the management of the third-party risk.
Suppliers, however, have their own challenges. Constant squeeze on costs from their clients reduces the profit margins making it increasingly difficult for vendors to prioritise security requirements implementation.
How do we make sure the suppliers we work with are trustworthy? How do we minimise the risk exposure from a potential incident? What level of assurance is required for a supplier?
These are the questions I’m going to answer in this blog.
Understanding business drivers and goals is essential for developing a third-party risk management approach. By analysing company’s corporate strategy I was able to derive multiple business attributes relevant to the shareholders. One of them stands out: Trusted. I’m going to disregard other attributes and focus on this one for the purposes of this case study. Not only it is important for the company to be trusted by its customers, but trustworthiness is also something I’m going to explore in this blog from the third-party relationship standpoint.
After a workshop with the CIO and IT managers in various business units, I’ve defined the following IT attributes supporting the main business attribute (Trusted): Transparent, Assured and Managed.
How does the security function support the wider IT objectives and corresponding attributes? After a number of workshops and analysing the security strategy document I’ve managed to create a number of security attributes. Below is a simplified example correlating to the business and IT attributes in scope:
Dealing with customers and managing relationships with them is one of the core activities of the company. As discussed above, being trusted by the customers is one of the main values of the organisation. IT department through the implementation of their technology strategy supported the business stakeholders in Sales and Marketing to outsource customer relationship management platform to a third party provider. A cloud-based solution has been chosen to fulfill this requirement.
A combination of attribute profiling, trust modelling and risk analysis is used to assess the degree of assurance required and compare third-party providers. Below is a recommended approach based on the attributes defined.
Security attributes mapping
Based on the internal security policy the following questionnaire has been developed to assess the supplier. Responses from the supplier have been omitted to preserve confidentiality. Below is a short excerpt from one of the sections of the questionnaire related to cloud services.
|Are terms of services and liabilities clearly defined in service agreements?||Governed|
|Are escrow arrangements in supplier contract agreement and cloud service agreements registered with procurement and documented in cloud service register.||Identified|
|Are physical security and environmental controls present in the data centre that contains company data?||Integrated|
|Are procedures for user authentication, authorization and access termination documented?||Access-Controlled|
|Has the Business Continuity Plan been reviewed and approved by the executive management?||Governed|
|How often is the Business Continuity Plans and Disaster Recovery Plans tested?||Available|
|Is there a specific Recovery Time Objective(s) (RTO) and Recovery Point Objective(s) (RPO)? If yes, specify the RTO and RPO for the company services.||Available|
|Are default settings customized to implement strong encryption for authentication and transmission?||Access-Controlled|
Attribute compliance is assessed based on the questionnaire answers, as every question is mapped to a specific attribute. Where a specific combination of an attribute corresponds to multiple questions, all answers are rated separately then an average rating for that attribute weight is calculated. Exceptions apply where certain specific questions are identified to have priority (higher level of impact on attribute compliance) over the other questions mapped to the same attribute. Expert judgement is applied to analyse such situations.
Attributes are evaluated with three main levels:
- High level of compliance with policy (Green),
- Medium level of compliance with policy (Amber),
- Low level of compliance with policy (Red)
I completed my SABSA Foundation training, passed the exam and earned the.SABSA Chartered Security Architect credential.
SABSA is a proven methodology for developing business-driven, risk and opportunity focused Security Architectures at both enterprise and solutions level that traceably support business objectives. It is also widely used for Information Assurance Architectures, Risk Management Frameworks, and to align and seamlessly integrate security and risk management into IT Architecture methods and frameworks.
SABSA is comprised of a series of integrated frameworks, models, methods and processes, used independently or as an holistic integrated enterprise solution, including:
- Business Requirements Engineering Framework (known as Attributes Profiling)
- Risk and Opportunity Management Framework
- Policy Architecture Framework
- Security Services-Oriented Architecture Framework
- Governance Framework
- Security Domain Framework
- Through-life Security Service Management & Performance Management Framework