Key Security Principles and Concepts

# Chapter three or more: Core Security Principles and Concepts

Ahead of diving further into threats and defenses, it's essential in order to establish the essential principles that underlie application security. These kinds of core concepts are the compass through which security professionals find their way decisions and trade-offs. They help reply why certain adjustments are necessary in addition to what goals all of us are trying to achieve. Several foundational models and concepts slowly move the design plus evaluation of safe systems, the nearly all famous being the CIA triad plus associated security principles.

## The CIA Triad – Discretion, Integrity, Availability

At the heart of information protection (including application security) are three principal goals:

1. **Confidentiality** – Preventing illegal entry to information. In simple terms, maintaining secrets secret. Just those who are authorized (have typically the right credentials or perhaps permissions) should be able to see or use very sensitive data. According in order to NIST, confidentiality indicates "preserving authorized limitations on access and even disclosure, including methods for protecting individual privacy and proprietary information"​
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. Breaches regarding confidentiality include new trends like data water leaks, password disclosure, or perhaps an attacker studying someone else's e-mail. A real-world instance is an SQL injection attack that dumps all end user records from a new database: data of which should have been confidential is subjected to the particular attacker. The opposite of confidentiality is disclosure​
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– when details is showed those not authorized to see it.

a couple of. **Integrity** – Protecting data and devices from unauthorized customization.  dictionary attack  means of which information remains accurate and trustworthy, and even that system functions are not interfered with. For illustration, if the banking app displays your accounts balance, integrity steps ensure that a great attacker hasn't illicitly altered that balance either in transit or in the particular database. Integrity can easily be compromised by simply attacks like tampering (e. g., transforming values in a WEB LINK to access someone else's data) or even by faulty computer code that corrupts files. A classic mechanism to make certain integrity will be the utilization of cryptographic hashes or signatures – if the document or message will be altered, its personal will no lengthier verify. The opposite of integrity is definitely often termed alteration – data getting modified or damaged without authorization​
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3. **Availability** – Making sure systems and files are accessible when needed. Even if info is kept key and unmodified, it's of little employ in the event the application will be down or inaccessible. Availability means of which authorized users can easily reliably access typically the application and their functions in some sort of timely manner. Dangers to availability incorporate DoS (Denial of Service) attacks, where attackers flood the server with targeted traffic or exploit a new vulnerability to crash the device, making it unavailable to legit users. Hardware failures, network outages, or perhaps even design issues that can't handle pinnacle loads are likewise availability risks. The particular opposite of supply is often identified as destruction or refusal – data or perhaps services are damaged or withheld​
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. The particular Morris Worm's influence in 1988 seemed to be a stark prompt of the need for availability: it didn't steal or transform data, but by making systems crash or slow (denying service), it caused key damage​
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These a few – confidentiality, integrity, and availability – are sometimes called the "CIA triad" and are considered the three pillars regarding security. Depending about the context, a good application might prioritize one over the others (for example of this, a public media website primarily cares that it's obtainable as well as content ethics is maintained, privacy is much less of a great issue considering that the articles is public; more over, a messaging iphone app might put discretion at the best of its list). But a protected application ideally ought to enforce all three to be able to an appropriate level. Many security controls can be realized as addressing a single or more of these pillars: encryption works with confidentiality (by scrambling data so only authorized can read it), checksums in addition to audit logs help integrity, and redundancy or failover systems support availability.

## The DAD Triad (Opposites of CIA)

Sometimes it's helpful to remember the flip side associated with the CIA triad, often called DADDY:

- **Disclosure** – Unauthorized access to be able to information (breach regarding confidentiality).
- **Alteration** – Unauthorized alter of information (breach associated with integrity).
- **Destruction/Denial** – Unauthorized damage info or denial of service (breach of availability).

Safety measures efforts aim to be able to prevent DAD final results and uphold CIA. A single assault can involve several of these factors. One example is, a ransomware attack might equally disclose data (if the attacker steals a copy) and even deny availability (by encrypting the victim's copy, locking all of them out). A internet exploit might change data in the database and thereby break the rules of integrity, etc.

## Authentication, Authorization, and Accountability (AAA)

Inside securing applications, specifically multi-user systems, we rely on additional fundamental concepts also known as AAA:

1. **Authentication** – Verifying the particular identity of the user or method. Whenever you log inside with an account information (or more securely with multi-factor authentication), the system is authenticating you – making certain you are usually who you claim to be. Authentication answers the query: Who are you? Typical methods include security passwords, biometric scans, cryptographic keys, or tokens. A core principle is the fact authentication ought to be strong enough to be able to thwart impersonation. Weak authentication (like easily guessable passwords or no authentication high should be) is really a frequent cause of breaches.

2. **Authorization** – Once identification is established, authorization settings what actions or perhaps data the authenticated entity is permitted to access. This answers: Precisely what are an individual allowed to perform? For example, right after you sign in, a great online banking program will authorize that you see your own account details yet not someone else's. Authorization typically entails defining roles or perhaps permissions. The weeknesses, Broken Access Handle, occurs when these kinds of checks fail – say, an attacker finds that by changing a list IDENTIFICATION in an WEB LINK they can see another user's data for the reason that application isn't properly verifying their authorization. In reality, Broken Access Manage was recognized as typically the number one web application risk found in the 2021 OWASP Top 10, seen in 94% of programs tested​
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, illustrating how pervasive and important proper authorization is.

three or more. **Accountability** (and Auditing) – This appertains to the ability to track actions in the particular system to the accountable entity, which will implies having proper visiting and audit trails. If something will go wrong or suspect activity is diagnosed, we need to be able to know who would what. Accountability will be achieved through visiting of user behavior, and by getting tamper-evident records. It works hand-in-hand with authentication (you can only hold someone responsible knowing which account was performing an action) and together with integrity (logs by themselves must be protected from alteration). In application security, establishing good logging and even monitoring is crucial for both uncovering incidents and performing forensic analysis following an incident. Because we'll discuss found in a later section, insufficient logging and monitoring enables breaches to go hidden – OWASP details this as an additional top 10 issue, writing that without correct logs, organizations may well fail to notice an attack till it's far too late​
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Sometimes you'll notice an expanded acronym like IAAA (Identification, Authentication, Authorization, Accountability) which just breaks or cracks out identification (the claim of personality, e. g. getting into username, before real authentication via password) as a separate step. But typically the core ideas continue to be exactly the same. A protected application typically enforces strong authentication, rigid authorization checks for every request, in addition to maintains logs regarding accountability.

## Theory of Least Opportunity

One of the most important design and style principles in safety is to provide each user or component the bare minimum privileges necessary to perform its operate, and no more. This is the principle of least freedom. In practice, it means if an program has multiple functions (say admin vs regular user), typically the regular user company accounts should have no ability to perform admin-only actions. If the web application wants to access a new database, the repository account it employs should have permissions just for the precise dining tables and operations necessary – for example, when the app never needs to delete data, the DB account shouldn't in fact have the REMOVE privilege. By constraining privileges, even though a great attacker compromises the user account or a component, the damage is contained.

A bare example of not really following least privilege was the Funds One breach of 2019: a misconfigured cloud permission authorized a compromised element (a web app firewall) to access all data from an S3 storage space bucket, whereas when that component acquired been limited in order to only certain data, the breach impact might have been a long way smaller​
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. Least privilege furthermore applies with the program code level: when a component or microservice doesn't need certain accessibility, it shouldn't have it. Modern container orchestration and foriegn IAM systems ensure it is easier to implement granular privileges, yet it requires careful design.

## Security in Depth

This specific principle suggests of which security should become implemented in overlapping layers, so that in the event that one layer does not work out, others still provide protection. Put simply, don't rely on any single security handle; assume it may be bypassed, and have additional mitigations in place. With regard to an application, security in depth might mean: you validate inputs on typically the client side for usability, but an individual also validate all of them on the server side (in case a good attacker bypasses the consumer check). You protected the database at the rear of an internal firewall, however you also compose code that investigations user permissions prior to queries (assuming a good attacker might breach the network). If using encryption, an individual might encrypt sensitive data within the data source, but also impose access controls at the application layer plus monitor for unusual query patterns. Protection in depth is usually like the layers of an onion – an assailant who gets via one layer need to immediately face one more. This approach counter tops the reality that no individual defense is certain.

For example, imagine an application depends on a net application firewall (WAF) to block SQL injection attempts. Protection comprehensive would claim the applying should continue to use safe coding practices (like parameterized queries) to sanitize inputs, in situation the WAF does not show for a novel attack. A real circumstance highlighting this was initially the truth of particular web shells or injection attacks that were not identified by security filtration systems – the internal application controls next served as typically the final backstop.

## Secure by Design and Secure simply by Default

These connected principles emphasize generating security an essential consideration from the start of design and style, and choosing safe defaults. "Secure by design" means you plan the system buildings with security inside mind – intended for instance, segregating very sensitive components, using tested frameworks, and considering how each design and style decision could introduce risk. "Secure by default" means once the system is stationed, it should default in order to the most dependable options, requiring deliberate actions to make that less secure (rather compared to the other approach around).

An example of this is default account policy: a securely designed application may possibly ship with no default admin password (forcing the installer to be able to set a solid one) – because opposed to creating a well-known default username and password that users may forget to change. Historically, many computer software packages are not secure by default; they'd install with available permissions or trial databases or debug modes active, and when an admin chosen not to lock them straight down, it left holes for attackers. With time, vendors learned to invert this: right now, databases and operating systems often come using secure configurations out of the package (e. g., remote access disabled, example users removed), in addition to it's up in order to the admin in order to loosen if definitely needed.

For designers, secure defaults indicate choosing safe collection functions by default (e. g., arrears to parameterized queries, default to outcome encoding for net templates, etc. ). It also implies fail safe – if an element fails, it should fail in a protected closed state quite than an unsafe open state. For instance, if an authentication service times out and about, a secure-by-default approach would deny access (fail closed) rather than allow that.

## Privacy by Design

Idea, carefully related to safety by design, features gained prominence especially with laws like GDPR. It means that applications should always be designed not just in end up being secure, but for regard users' privacy from the ground upwards. Used, this may possibly involve data minimization (collecting only exactly what is necessary), transparency (users know exactly what data is collected), and giving consumers control of their data. While privacy is definitely a distinct site, it overlaps intensely with security: a person can't have level of privacy if you can't secure the personal data you're liable for. Lots of the most severe data breaches (like those at credit bureaus, health insurance companies, etc. ) are usually devastating not simply because of security failure but because they will violate the personal privacy of a lot of individuals. Thus, modern application security often functions hand in palm with privacy things to consider.

## Threat Modeling

A vital practice inside secure design is definitely threat modeling – thinking like an attacker to anticipate what could make a mistake. During threat modeling, architects and programmers systematically go through the type of a good application to recognize potential threats and vulnerabilities. They question questions like: Exactly what are we developing? What can go wrong? And what will many of us do regarding it? A single well-known methodology intended for threat modeling is definitely STRIDE, developed from Microsoft, which holds for six kinds of threats: Spoofing identification, Tampering with information, Repudiation (deniability involving actions), Information disclosure, Denial of service, and Elevation associated with privilege.

By walking through each component of a system and even considering STRIDE risks, teams can reveal dangers that may not be evident at first glimpse. For example, consider a simple online payroll application. Threat modeling might reveal that will: an attacker can spoof an employee's identity by guessing the session expression (so we want strong randomness), may tamper with wage values via a new vulnerable parameter (so we need insight validation and server-side checks), could carry out actions and after deny them (so we need good review logs to avoid repudiation), could take advantage of an information disclosure bug in an error message to glean sensitive info (so we need user-friendly but hazy errors), might effort denial of support by submitting a new huge file or heavy query (so we need rate limiting and resource quotas), or try out to elevate privilege by accessing administrative functionality (so all of us need robust access control checks). By means of this process, security requirements and countermeasures become much clearer.

Threat modeling is usually ideally done early on in development (during the design phase) as a result that security is built in from the start, aligning with the particular "secure by design" philosophy. It's the evolving practice – modern threat modeling may also consider mistreatment cases (how can the system end up being misused beyond the particular intended threat model) and involve adversarial thinking exercises. We'll see its meaning again when discussing specific vulnerabilities in addition to how developers can foresee and prevent them.

## Chance Management

Not every protection issue is every bit as critical, and resources are always in short supply. So another principle that permeates program security is risk management. This involves evaluating the likelihood of a menace along with the impact had been it to happen. Risk is frequently informally considered as an event of these a couple of: a vulnerability that's easy to exploit in addition to would cause serious damage is high risk; one that's theoretical or would have minimal influence might be decrease risk. Organizations often perform risk checks to prioritize their security efforts. With regard to example, an on the internet retailer might figure out the risk associated with credit card fraud (through SQL injections or XSS resulting in session hijacking) is incredibly high, and hence invest heavily found in preventing those, whilst the chance of someone creating minor defacement in a less-used web page might be approved or handled along with lower priority.

Frames like NIST's or ISO 27001's risk management guidelines help inside systematically evaluating in addition to treating risks – whether by minify them, accepting them, transferring them (insurance), or avoiding them by changing enterprise practices.

One concrete consequence of risk management in application protection is the creation of a threat matrix or chance register where potential threats are detailed along with their severity. This specific helps drive decisions like which pests to fix very first or where in order to allocate more screening effort.  https://www.youtube.com/watch?v=vZ5sLwtJmcU 's likewise reflected in patch management: if some sort of new vulnerability is usually announced, teams will assess the danger to their application – is this exposed to of which vulnerability, how serious is it – to determine how urgently to utilize the patch or workaround.

## Security vs. Usability vs. Cost

The discussion of concepts wouldn't be complete without acknowledging the real-world balancing action. Security measures can introduce friction or cost. Strong authentication might mean even more steps for the consumer (like 2FA codes); encryption might slow down performance somewhat; extensive logging may well raise storage charges. A principle to adhere to is to seek balance and proportionality – security should become commensurate with the particular value of what's being protected. Extremely burdensome security that will frustrates users can be counterproductive (users will dsicover unsafe workarounds, intended for instance). The artwork of application protection is finding options that mitigate dangers while preserving the good user knowledge and reasonable cost. Fortunately, with modern techniques, many security measures can be made quite smooth – for example, single sign-on remedies can improve each security (fewer passwords) and usability, and efficient cryptographic your local library make encryption rarely noticeable when it comes to functionality.

In summary, these types of fundamental principles – CIA, AAA, the very least privilege, defense in depth, secure by design/default, privacy considerations, threat modeling, and risk management – form the particular mental framework intended for any security-conscious specialist. They will look repeatedly throughout information as we examine specific technologies plus scenarios. Whenever a person are unsure about a security choice, coming back to be able to these basics (e. g., "Am We protecting confidentiality? Are generally we validating ethics? Are we reducing privileges? Can we include multiple layers associated with defense? ") can easily guide you into a more secure result.

Using these principles in mind, we are able to at this point explore the exact dangers and vulnerabilities that plague applications, plus how to guard against them.