Main Security Principles plus Concepts

# Chapter 3: Core Security Rules and Concepts

Before diving further straight into threats and defense, it's essential to establish the fundamental principles that underlie application security. These core concepts will be the compass by which security professionals navigate decisions and trade-offs. They help respond to why certain adjustments are necessary in addition to what goals we all are trying to be able to achieve. Several foundational models and principles slowly move the design and evaluation of protected systems, the virtually all famous being the CIA triad in addition to associated security guidelines.

## The CIA Triad – Confidentiality, Integrity, Availability

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

1. **Confidentiality** – Preventing unauthorized use of information. Within simple terms, trying to keep secrets secret. Only those who will be authorized (have the particular right credentials or perhaps permissions) should get able to see or use delicate data. According to NIST, confidentiality implies "preserving authorized limitations on access and disclosure, including methods for protecting personalized privacy and amazing information"​
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. Breaches involving confidentiality include tendency like data leakages, password disclosure, or perhaps an attacker reading someone else's e-mails. A real-world example is an SQL injection attack of which dumps all user records from a database: data that will should are already confidential is encountered with the particular attacker. The other associated with confidentiality is disclosure​
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– when details is revealed to these not authorized to see it.

two. **Integrity** – Safeguarding data and systems from unauthorized modification. Integrity means of which information remains accurate and trustworthy, and even that system features are not tampered with. For instance, in case a banking application displays your consideration balance, integrity procedures ensure that a good attacker hasn't illicitly altered that stability either in passage or in the database. Integrity can certainly be compromised by attacks like tampering (e. g., altering values within a WEB LINK to access someone else's data) or by faulty signal that corrupts information. A classic mechanism to assure integrity is definitely the utilization of cryptographic hashes or validations – when a document or message is definitely altered, its trademark will no more time verify. The reverse of of integrity is usually often termed change – data being modified or dangerous without authorization​
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3. **Availability** – Guaranteeing systems and files are accessible as needed. Even if info is kept magic formula and unmodified, it's of little use in case the application will be down or unreachable. Availability means that authorized users can easily reliably access the particular application and the functions in some sort of timely manner. Dangers to availability consist of DoS (Denial involving Service) attacks, in which attackers flood a server with targeted visitors or exploit the vulnerability to crash the machine, making that unavailable to legit users. Hardware failures, network outages, or even design issues that can't handle pinnacle loads are also availability risks. The opposite of accessibility is often described as destruction or refusal – data or even services are ruined or withheld​
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. The particular Morris Worm's effect in 1988 seemed to be a stark reminder of the importance of availability: it didn't steal or change data, but by making systems crash or slow (denying service), it caused significant damage​
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These 3 – confidentiality, integrity, and availability – are sometimes referred to as the "CIA triad" and are considered as the three pillars associated with security. Depending upon the context, a good application might prioritize one over the particular others (for illustration, a public news website primarily cares about you that it's offered and its content ethics is maintained, discretion is less of a good issue because the written content is public; on the other hand, a messaging application might put discretion at the top rated of its list). But a protect application ideally should enforce all to an appropriate diploma. Many security regulates can be realized as addressing 1 or more of such pillars: encryption works with confidentiality (by trying data so only authorized can read it), checksums plus audit logs support integrity, and redundancy or failover methods support availability.

## The DAD Triad (Opposites of CIA)

Sometimes it's useful to remember the particular flip side regarding the CIA triad, often called DADDY:

- **Disclosure** – Unauthorized access in order to information (breach regarding confidentiality).
- **Alteration** – Unauthorized transform info (breach regarding integrity).
- **Destruction/Denial** – Unauthorized break down details or refusal of service (breach of availability).

Safety efforts aim in order to prevent DAD outcomes and uphold CIA. A single strike can involve multiple of these factors. One example is, a ransomware attack might equally disclose data (if the attacker abducts a copy) plus deny availability (by encrypting the victim's copy, locking them out). A net exploit might modify data within a repository and thereby break integrity, and so forth.

## Authentication, Authorization, and even Accountability (AAA)

Inside securing applications, specially multi-user systems, all of us rely on added fundamental concepts often referred to as AAA:

1. **Authentication** – Verifying the particular identity of a great user or system. When you log within with an account information (or more securely with multi-factor authentication), the system is usually authenticating you – making certain you are who you state to be. Authentication answers the question: Which are you? Typical methods include security passwords, biometric scans, cryptographic keys, or bridal party. A core basic principle is that authentication need to be strong enough to be able to thwart impersonation. Weak  identity and access management  (like quickly guessable passwords or even no authentication high should be) is a frequent cause of breaches.

2. **Authorization** – Once identification is established, authorization settings what actions or even data the authenticated entity is granted to access. That answers: Precisely what are a person allowed to do? For example, following you sign in, a good online banking application will authorize one to see your personal account details but not someone else's. Authorization typically consists of defining roles or permissions. A weakness, Broken Access Control, occurs when these checks fail – say, an assailant finds that by changing a list ID in an LINK they can look at another user's files for the reason that application isn't properly verifying their own authorization. In simple fact, Broken Access Control was referred to as typically the number one net application risk in the 2021 OWASP Top 10, present in 94% of apps tested​
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, illustrating how pervasive and important proper authorization is.

a few. **Accountability** (and Auditing) – This appertains to the ability to search for actions in the particular system towards the liable entity, which usually implies having proper visiting and audit paths. If something will go wrong or shady activity is detected, we need to be able to know who did what. Accountability is definitely achieved through working of user actions, and by possessing tamper-evident records. Functions hand-in-hand with authentication (you can just hold someone accountable once you learn which account was performing an action) and with integrity (logs themselves must be protected from alteration). Within application security, setting up good logging plus monitoring is essential for both sensing incidents and executing forensic analysis right after an incident. While we'll discuss found in a later phase, insufficient logging and monitoring enables removes to go undetected – OWASP details this as one more top 10 issue, remembering that without proper logs, organizations may fail to notice an attack until it's far too late​
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Sometimes you'll notice an expanded phrase like IAAA (Identification, Authentication, Authorization, Accountability) which just breaks out identification (the claim of identity, e. g. entering username, before actual authentication via password) as a distinct step. But typically the core ideas remain the same. A secure application typically enforces strong authentication, stringent authorization checks regarding every request, and maintains logs with regard to accountability.

## Theory of Least Freedom

One of typically the most important design and style principles in security is to give each user or even component the minimum privileges necessary to perform its operate, and no more. This particular is the theory of least freedom. In practice, it indicates if an app has multiple roles (say admin versus regular user), typically the regular user balances should have no capability to perform admin-only actions. If  https://docs.shiftleft.io/sast/integrations/jetbrains-plugin  wants to access a database, the repository account it makes use of really should have permissions simply for the precise furniture and operations needed – by way of example, in the event that the app in no way needs to delete data, the DEUTSCHE BAHN account shouldn't still have the REMOVE privilege. By constraining privileges, even when a good attacker compromises the user account or a component, the damage is contained.

A kampfstark example of not following least privilege was the Money One breach involving 2019: a misconfigured cloud permission authorized a compromised element (a web program firewall) to get all data by an S3 safe-keeping bucket, whereas if that component experienced been limited to be able to only certain data, the particular breach impact would likely have been far smaller​
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. Least privilege likewise applies on the code level: in case a component or microservice doesn't need certain accessibility, it shouldn't experience it. Modern container orchestration and cloud IAM systems ensure it is easier to put into action granular privileges, but it requires thoughtful design.

## Security in Depth

This particular principle suggests that will security should become implemented in overlapping layers, in order that in case one layer neglects, others still give protection. Put simply, don't rely on any single security manage; assume it can easily be bypassed, and even have additional mitigations in place. Intended for an application, security in depth may possibly mean: you confirm inputs on the client side intended for usability, but a person also validate all of them on the server side (in case the attacker bypasses the consumer check). You safe the database right behind an internal fire wall, but you also create code that investigations user permissions just before queries (assuming an attacker might break the network). In the event that using encryption, an individual might encrypt delicate data inside the repository, but also enforce access controls with the application layer in addition to monitor for uncommon query patterns. Protection in depth will be like the levels of an red onion – an opponent who gets via one layer need to immediately face another. This approach counter tops the point that no solitary defense is certain.

For example, suppose an application is dependent on a net application firewall (WAF) to block SQL injection attempts. Defense in depth would state the application form should nonetheless use safe coding practices (like parameterized queries) to sanitize inputs, in case the WAF misses a novel harm. A real scenario highlighting this was initially the truth of particular web shells or injection attacks that were not recognized by security filtration systems – the inner application controls next served as the final backstop.

## Secure by Style and Secure simply by Default

These related principles emphasize generating security an essential consideration from the start of design, and choosing risk-free defaults. "Secure by design" means you want the system structure with security found in mind – with regard to instance, segregating sensitive components, using tested frameworks, and contemplating how each design and style decision could expose risk. "Secure by simply default" means if the system is implemented, it should default to be able to the most secure settings, requiring deliberate actions to make that less secure (rather than the other way around).

An illustration is default account policy: a firmly designed application may possibly ship without having predetermined admin password (forcing the installer in order to set a strong one) – because opposed to using a well-known default password that users may possibly forget to change. Historically, many application packages were not safeguarded by default; they'd install with wide open permissions or test databases or debug modes active, if an admin neglected to lock them lower, it left slots for attackers. After some time, vendors learned in order to invert this: right now, databases and operating systems often come along with secure configurations out of the box (e. g., distant access disabled, sample users removed), in addition to it's up in order to the admin to be able to loosen if absolutely needed.

For developers, secure defaults mean choosing safe library functions by arrears (e. g., arrears to parameterized concerns, default to result encoding for web templates, etc. ). It also signifies fail safe – if an aspect fails, it need to fail in the safeguarded closed state instead than an insecure open state. As an example, if an authentication service times out there, a secure-by-default process would deny accessibility (fail closed) quite than allow this.

## Privacy by Design

This concept, closely related to protection by design, features gained prominence especially with laws like GDPR. It means of which applications should be designed not just in always be secure, but for respect users' privacy through the ground upwards. Used, this may well involve data minimization (collecting only what is necessary), openness (users know exactly what data is collected), and giving consumers control over their information. While privacy is a distinct domain, it overlaps seriously with security: you can't have privateness if you can't secure the individual data you're responsible for. Lots of the worst data breaches (like those at credit bureaus, health insurers, etc. ) usually are devastating not only as a result of security failing but because that they violate the privateness of millions of individuals. Thus, modern application security often works hand in hand with privacy things to consider.

## Threat Building

The practice throughout secure design is definitely threat modeling – thinking like the attacker to anticipate what could fail. During threat which, architects and developers systematically go due to the type of an application to recognize potential threats in addition to vulnerabilities. They inquire questions like: Precisely what are we building? What can go wrong? And what will we do about this? One particular well-known methodology regarding threat modeling is STRIDE, developed with Microsoft, which holders for six types of threats: Spoofing id, Tampering with information, Repudiation (deniability of actions), Information disclosure, Denial of services, and Elevation associated with privilege.

By going for walks through each element of a system and considering STRIDE dangers, teams can discover dangers that might not be clear at first glimpse. For example, think about a simple online payroll application. Threat building might reveal that: an attacker may spoof an employee's identity by guessing the session symbol (so we need to have strong randomness), may tamper with wage values via some sort of vulnerable parameter (so we need insight validation and server-side checks), could conduct actions and later on deny them (so we need good review logs to prevent repudiation), could exploit an information disclosure bug in an error message to be able to glean sensitive details (so we need user-friendly but vague errors), might effort denial of service by submitting a new huge file or even heavy query (so we need rate limiting and resource quotas), or attempt to elevate benefit by accessing administrator functionality (so all of us need robust gain access to control checks). By way of this process, protection requirements and countermeasures become much better.

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

## Hazard Management

Not every safety measures issue is similarly critical, and resources are always partial. So another concept that permeates app security is risikomanagement. This involves determining the probability of a danger along with the impact had been it to happen. Risk is frequently informally considered as an event of these 2: a vulnerability that's simple to exploit and would cause extreme damage is large risk; one that's theoretical or would certainly have minimal influence might be reduce risk. Organizations often perform risk assessments to prioritize their very own security efforts. For example, an on the internet retailer might decide that this risk involving credit card theft (through SQL injections or XSS resulting in session hijacking) is incredibly high, and hence invest heavily inside preventing those, although the chance of someone creating minor defacement on a less-used webpage might be recognized or handled using lower priority.

Frames like NIST's or perhaps ISO 27001's risk management guidelines help inside systematically evaluating plus treating risks – whether by mitigating them, accepting all of them, transferring them (insurance), or avoiding them by changing organization practices.

One tangible consequence of risk management in application security is the generation of a threat matrix or chance register where prospective threats are detailed along with their severity. This particular helps drive choices like which bugs to fix 1st or where to allocate more assessment effort. It's in addition reflected in repair management: if a new new vulnerability will be announced, teams will certainly assess the threat to their app – is that exposed to that vulnerability, how severe is it – to make the decision how urgently to make use of the plot or workaround.

## Security vs. Usability vs. Cost

A discussion of rules wouldn't be finish without acknowledging typically the real-world balancing work. Security measures can introduce friction or even cost. Strong authentication might mean even more steps to have a customer (like 2FA codes); encryption might impede down performance a bit; extensive logging may possibly raise storage costs. A principle to follow is to seek balance and proportionality – security should become commensurate with the particular value of what's being protected. Excessively burdensome security of which frustrates users may be counterproductive (users will dsicover unsafe workarounds, intended for instance). The fine art of application protection is finding solutions that mitigate hazards while preserving a good user experience and reasonable expense. Fortunately, with contemporary techniques, many security measures can become made quite smooth – for example of this, single sign-on remedies can improve both security (fewer passwords) and usability, in addition to efficient cryptographic libraries make encryption barely noticeable regarding overall performance.

In summary, these types of fundamental principles – CIA, AAA, least privilege, defense detailed, secure by design/default, privacy considerations, risk modeling, and risikomanagement – form the mental framework regarding any security-conscious practitioner. They will look repeatedly throughout information as we examine specific technologies and even scenarios. Whenever an individual are unsure about a security selection, coming back to be able to these basics (e. g., "Am My partner and i protecting confidentiality? Are we validating sincerity? Are we lessening privileges? Do we possess multiple layers associated with defense? ") can guide you into a more secure result.

With these principles on mind, we can today explore the exact dangers and vulnerabilities of which plague applications, in addition to how to defend against them.