Device health consists of compliance with device configuration and device state. Default system configuration at start-up is secure. To effectively isolate your apps, you need to have container isolation and network isolation. It cannot tell you whether or not a system was exploited. Unified time service is needed for a secure audit service. In a zero trust architecture, this chokepoint isn’t available and protective monitoring has to be moved onto each device. Implications: If this principle is not implemented, inappropriately  data (e.g. Rationale: While the trend toward shared infrastructure has considerable merit in many cases, it is not universally applicable. It is easier to upgrade small pieces of a system than huge blobs. Your organisation should use a single user directory and create accounts that are linked to individuals. Systems, data, and technologies must be protected from unauthorized access and manipulation. The power of a zero trust architecture comes from the access policies you define. Designers sometimes fail to account for the fact that authenticated and properly authorized users can also be attackers! On modern devices and platforms, strong multi-factor authentication can be achieved with a good user experience. A good example is authentication, where common standards such as OpenID Connect or SAML allow you to use a single directory service to authenticate to many services. 1. Additionally, though, it is wise to keep function pointer use to a minimum, and to restrict to simple cases, to make sure that also humans can determine accurately and with modest effort which functions may be evoked. However, even small organizations can prepare a document that states organization policy and makes explicit computer security responsibilities. Statement: Provide assurance that the system is, and continues to be, resilient in the face of expected threats. Prefer services with built-in support for zero trust. Note that with just ten conditional compilation directives, there could be up to 2^10 (i.e., 1024) possible versions of the code, each of which would have to be tested – causing a significant increase in the required test effort. The king does not rely on one barrier alone to protect his inner circle of priceless jewels and nobility. In cases where the sensitivity or criticality of the information is high, organizations may want to limit the number of systems on which that data is stored and isolate them, either physically or logically. In modifying or adjusting security goals, an acceptance of greater risk and cost may be inevitable. Secure the weakest link 2. In some cases, organizations may be required to disclose information obtained through auditing mechanisms to appropriate third parties. If the traffic doesn’t match, the IPS can block it. Types of attacks to resist: An architecture built on good security … Statement: Declare data objects at the smallest possible level of scope. There are watchmen to look out for invaders who can see them coming for miles. There is no excuse for any serious software development effort not to make use of this technology. In most cases, though, the return value of a function should not be ignored, especially if error return values must be propagated up the function call chain. Enforcement is usually session based, policies will be assessed as a connection is established and the broker provides a short lived access token which allows users connect to the services they originally requested. Furthermore you can use or start with security models we present in this reference architecture as well. A strict value for N=1, but in some cases using N=2 can be justified. Statement: Computer Security Should Be Cost-Effective. Data should only be pushed to the DMZ and never flow back into the more secure control or operations levels. It does this by examining the types of packets and comparing them with the IP addresses, ports and sequence numbers of packets, etc., going over the connections. This segment also helps synchronize sequence numbers between devices. As with many architectural decisions, the principles, which do not necessarily guarantee security, at times may exist in opposition to each other, so appropriate tradeoffs must be made. In the previous principles we talked about building trust in a user’s identity, their devices and services. And so on. If one security service fails the security system should still be resistant against threads. Statement: Use a authentication mechanism that cannot be bypassed or tampered with. Rationale: As mission and business processes and the threat environment change, security requirements and technical protection methods must be updated. These principles, like all security principles, are intended to help you design and deploy a secure end-to-end, zero trust architecture. Statement: Implement tailored system security measures to meet organizational security goals. In applications and systems with multiple components, it is common for an application to need to make a request on behalf of an end user to another service to fulfill this users request. In general, all external systems should be considered insecure. Statement: Assume that external systems are insecure. This article is not going to get into a discussion of the OSI model of communications, but for a quick refresher, Layer 1 is the physical layer, Layer 2 is the data link layer, and Layer 3 is the network layer. Using a device management service, apply these policies to devices and enforce them, then continuously check that devices are compliant. That is, when a client wants to establish a session with a server, for example, the client initiates the communication with a synchronization segment and establishes the connection. 2. For example, is secure boot enabled? Then there is the IPS/IDS like the watchmen on the ramparts and the firewall like the castle itself with a drawbridge, inspecting everything and everyone that comes into the inner circle. Implications: Stress under load and hard failure situations must be incorporated in the security test suite. With a unique blend of software based automation and managed services, RSI Security can assist all sizes of organizations in managing IT governance, risk management and compliance efforts (GRC). Network monitoring should be carried out on your local networks to identify rogue devices and help identify malicious activity, especially if you’re hosting on-premise services. Security principles denote the basic guidelines that should be used when designing a secure system. Security architecture principles are used to translate selected alternatives into basic ideas, standards, and guidelines for simplifying and organizing the construction, operation, and evolution of systems. Requirements for security vary, depending upon the particular IT system. The enforcement of this principle make sure that exceptions are always explicitly justified (and justifiable), with mechanical checkers flagging violations. Layered defense easily possible. If this principle is not implemented, consumers will not be able to detect and respond to inappropriate or malicious use of their service or data within reasonable time-scales. Host firewalls protect hosts as their name implies. Inventorying all assets and documenting this information will guide the development of security architecture. Alignment of business domains and security requirements. We recommend that you use a single policy engine and apply the full set of features it offers. Rationale: There are several very effective static source code analyzers on the market today, and quite a few freeware tools as well. You should also consider how you’ll offer access to the resources your organisation controls, to people from outside your organisation.   Statement: Design security to allow for regular adoption of new technology, including a secure and logical technology upgrade process. The demilitarized zone (DMZ) is also known as the outer perimeter network, and this is where public-facing servers such as the webserver, wireless access point, and remote systems reside. An audit report from a third party is required (in case of cloud sourcing). California Online Privacy Protection Act (CalOPPA), CryptoCurrency Security Standard (CCSS) / Blockchain, Factor analysis of information risk (FAIR) Assessment, NIST Special Publication (SP) 800-207 – Zero Trust Architecture, IT Security & Cybersecurity Awareness Training, Work from home cybersecurity tips – COVID19. Statement: A simple design is easier to test and validate. Statement: Underlaying infrastructure cannot be assumed safe. Defense-in-depth as a cybersecurity strategy takes a similar holistic approach to defense, rather than a specific one-to-one control vs. threat style. Wherever possible, artifacts of end-user consent should be included with requests to back end services so that we can have greater confidence that this request originated from the end-user. The value and worst-case scenarios for a breach of these assets should also be considered and compared to the business’ tolerance for risk. Never store secrets (e.g. Other assets require hardware firewalls in line with the asset. Cloud based services and deployments enables flexibility, agility, scalability and performance to deliver services. Statement: Protect information while being processed, in transit, and in storage. All policies and procedures should reflect the principles of least privilege and need to know access. Implications: Verify the integrity and provenance of upgrade packages. When security is too hard to set up for a large population of the system’s users, it will never be configured, or it will not be configured properly. Statement: Security measurements should be open and transparent. In a zero trust architecture, inherent trust is removed from the network. security tests with manipulated headers.   Statement: Ensure proper security in the shutdown or disposal of a system. Statement: Services from others (departments, companies) should never (ever) be trusted. In more dubious cases, a comment should be present to explain why a return value is irrelevant. Multi-factor authentication (MFA) should be required as well as the monitoring of defined rules and connection states. This is often the case with calls to printf and close. If a zero trust architecture is implemented without considering existing services, they may be at higher risk as the network is assumed to be untrusted and hostile. It requires human analysis to determine what happened, and it does not monitor system console activity. Rationale: Security design should protect against services use of other layers or applications (also SAAS services). Rationale: Integrating security into the design phase saves money and time. When designing your systems, be sure to consider the context where code is executed, where data will go, and where data entering your system comes from. the proposed security and privacy principles and the sample requirements to start with. As always in security architecture, a risk managed approach is required. Many types of changes affect system security: technological developments (whether adopted by the system owner or available for use by others); connection to external networks; a change in the value or use of information; or the emergence of a new threat. Access should be based on the need to know and hardened to mitigate risk to acceptable levels. Rationale: The risk of unauthorized modification or destruction of data, disclosure of information, and denial of access to data while in transit should be considered along with the risks associated with data that is in storage or being processed. Rationale: Pointers are easily misused, even by experienced programmers. Rationale: Protecting secure logs is expensive. Observation of typical traffic patterns to develop a baseline of behavior can be compared to events on a daily basis. Options for addressing information risk should be reviewed so that informed and documented decisions are made about the treatment of risk. Authentication is not binary—users may be required to present minimal (such as a password) or more substantial (e.g. To enable authorisation decisions, access policies need to be defined, based on who can access which service or data, under which circumstances.   Statement: Establish secure defaults when system goes in error or exception status, or at default startup. Enforcement points will focus on properties of the network connection to control access, for example which network protocols can be used, the origin of the connection, the network segments that can communicate based on the policy. All these will be explained in brief in the subsequent sections: The rationale for the caution against conditional compilation is equally important. If using software defined perimeter (SDP), the policy enforcement point is usually the SDP controller that controls connections from a central location which may also be the Policy Engine. 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. Given that in a zero trust architecture, you can’t trust the network, services need to be designed to protect themselves from hostile networks. If you have any questions about our policy, we invite you to read more. Similarly, if an erroneous value of an object has to be diagnosed, the fewer the number of statements where the value could have been assigned; the easier it is to diagnose the problem. If the design, implementation, or security mechanisms are highly complex, then the likelihood of security vulnerabilities increases. This paper has only addressed top-level design considerations with the major types of equipment found at the perimeters of inner and outer networks. Consider the context and needs for privacy of personally identifiable information when designing solutions and mitigate accordingly. Security should also be designed into the business processes within which an IT system is used. Rationale: Security measures include people, operations, and technology. Are the latest operating system updates installed? Devices in a BYOD model should still have an identity linked to them but the confidence in that device’s identity may be lower. Rationale: Insecure protocols introduce security risks than can be easily avoided. This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License (CC BY-SA 4.0). Data security safeguards can be put in place to restrict access to “view only”, or “never see”. For example, if a client makes a request to a server for a service that sits behind the proxy, it will not be allowed to communicate directly with the server. It is also important to know the precise function of critical assets and the resources they depend on. These expectations can typically be summarized as providing sufficient resistance to both direct penetration and attempts to circumvent security controls. This includes establishing security policies, understanding the resulting security requirements, participating in the evaluation of security products, and finally in the engineering, design, implementation, and disposal of the system. Principles of Secure Design 1. An efficient and cost effective security capability should be able to enforce multiple security policies to protect multiple information domains without the need to separate (physically or logically) the information and respective information systems processing the data. IT-related risks to the mission/business vary over time and undergo periodic assessment. There may be one before an industrial control zone and one before an enterprise zone. 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