Primary Security Principles plus Concepts

# Chapter 3: Core Security Principles and Concepts

Ahead of diving further directly into threats and defenses, it's essential to be able to establish the important principles that underlie application security. These types of core concepts happen to be the compass by which security professionals navigate decisions and trade-offs. They help respond to why certain settings are necessary plus what goals we all are trying in order to achieve. Several foundational models and concepts slowly move the design and evaluation of protected systems, the nearly all famous being the particular CIA triad in addition to associated security principles.

## The CIA Triad – Privacy, Integrity, Availability

In the middle of information safety measures (including application security) are three main goals:

1. **Confidentiality** – Preventing illegal usage of information. Inside simple terms, trying to keep secrets secret. Only those who are usually authorized (have typically the right credentials or even permissions) should become able to view or use delicate data. According in order to NIST, confidentiality indicates "preserving authorized limitations on access in addition to disclosure, including method for protecting individual privacy and amazing information"​
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. Breaches involving confidentiality include phenomena like data leakages, password disclosure, or perhaps an attacker reading through someone else's e-mails. A real-world example of this is an SQL injection attack that dumps all customer records from a new database: data that will should have been confidential is exposed to the particular attacker. The other involving confidentiality is disclosure​
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– when info is showed all those not authorized in order to see it.

2. **Integrity** – Protecting data and devices from unauthorized modification. Integrity means that will information remains exact and trustworthy, in addition to that system functions are not interfered with. For instance, if a banking software displays your accounts balance, integrity steps ensure that the attacker hasn't illicitly altered that harmony either in passage or in the particular database. Integrity can easily be compromised by attacks like tampering (e. g., altering values within an URL to access someone else's data) or even by faulty computer code that corrupts data. A classic device to make sure integrity will be the utilization of cryptographic hashes or autographs – when a document or message will be altered, its trademark will no longer verify. The contrary of integrity is often termed amendment – data getting modified or corrupted without authorization​
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three or more. **Availability** – Making sure systems and info are accessible as needed. Even if data is kept secret and unmodified, it's of little employ when the application is definitely down or unreachable. Availability means that authorized users can reliably access the particular application and their functions in some sort of timely manner. Risks to availability contain DoS (Denial regarding Service) attacks, wherever attackers flood some sort of server with targeted visitors or exploit a vulnerability to impact the program, making that unavailable to genuine users. Hardware problems, network outages, or even design problems that can't handle peak loads are furthermore availability risks. The opposite of availability is often described as destruction or denial – data or perhaps services are demolished or withheld​
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. The Morris Worm's impact in 1988 has been a stark tip of the importance of availability: it didn't steal or alter data, but by making systems crash or even slow (denying service), it caused significant damage​
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These three – confidentiality, sincerity, and availability – are sometimes called the "CIA triad" and are considered as the three pillars involving security. Depending on the context, an application might prioritize one over the others (for example, a public information website primarily cares about you that it's accessible as well as content sincerity is maintained, discretion is much less of a good issue considering that the articles is public; conversely, a messaging app might put confidentiality at the leading of its list). But a safeguarded application ideally should enforce all three to be able to an appropriate degree. Many security handles can be recognized as addressing 1 or more of such pillars: encryption works with confidentiality (by trying data so only authorized can study it), checksums and audit logs help integrity, and redundancy or failover systems support availability.

## The DAD Triad (Opposites of CIA)

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

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

Protection efforts aim to be able to prevent DAD outcomes and uphold CIA. A single strike can involve several of these features. One example is, a ransomware attack might both disclose data (if the attacker steals a copy) and deny availability (by encrypting the victim's copy, locking all of them out). A net exploit might change data in the databases and thereby infringement integrity, etc.

## Authentication, Authorization, plus Accountability (AAA)

Throughout securing applications, especially multi-user systems, many of us rely on further fundamental concepts also known as AAA:

1. **Authentication** – Verifying typically the identity of a good user or program. Whenever you log in with an username and password (or more firmly with multi-factor authentication), the system is definitely authenticating you – making sure you usually are who you promise to be. Authentication answers the question: Which are you? Common methods include passwords, biometric scans, cryptographic keys, or tokens. A core principle is the fact that authentication need to be sufficiently strong to be able to thwart impersonation. Weakened authentication (like easily guessable passwords or no authentication high should be) can be a frequent cause associated with breaches.

2. **Authorization** – Once identification is established, authorization adjustments what actions or data the verified entity is allowed to access. It answers: Exactly what an individual allowed to perform? For example, right after you sign in, a great online banking app will authorize one to see your individual account details yet not someone else's. Authorization typically entails defining roles or perhaps permissions. The susceptability, Broken Access Control, occurs when these types of checks fail – say, an attacker finds that by changing a record ID in an URL they can look at another user's information for the reason that application isn't properly verifying their particular authorization. In reality, Broken Access Control was identified as the number one website application risk in the 2021 OWASP Top 10, present in 94% of apps tested​
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, illustrating how pervasive and important suitable authorization is.

3. ** https://docs.shiftleft.io/sast/ui-v2/reporting ** (and Auditing) – This appertains to the ability to track actions in the particular system for the accountable entity, which will indicates having proper visiting and audit tracks. If something goes wrong or shady activity is discovered, we need to know who do what. Accountability is achieved through working of user actions, and by having tamper-evident records. It works hand-in-hand with authentication (you can only hold someone dependable once you learn which accounts was performing an action) and with integrity (logs themselves must be guarded from alteration). Throughout application security, creating good logging and even monitoring is vital for both sensing incidents and performing forensic analysis after an incident. As we'll discuss in a later chapter, insufficient logging in addition to monitoring enables breaches to go undiscovered – OWASP lists this as one other top 10 issue, observing that without suitable logs, organizations might fail to observe an attack till it's far as well late​
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Sometimes you'll find an expanded acronym like IAAA (Identification, Authentication, Authorization, Accountability) which just breaks or cracks out identification (the claim of identity, e. g. getting into username, before real authentication via password) as an individual step. But typically the core ideas continue to be the same. A safeguarded application typically enforces strong authentication, rigid authorization checks intended for every request, and maintains logs with regard to accountability.

## Basic principle of Least Freedom

One of the particular most important design principles in protection is to give each user or even component the minimum privileges necessary to be able to perform its operate, without more. This kind of is the rule of least benefit. In practice, this means if an application has multiple tasks (say admin vs regular user), the regular user balances should have simply no ability to perform admin-only actions. If some sort of web application requirements to access some sort of database, the database account it uses really should have permissions simply for the specific desks and operations needed – by way of example, in the event that the app by no means needs to remove data, the DB account shouldn't even have the ERASE privilege. By constraining privileges, even if a good attacker compromises a great user account or perhaps a component, destruction is contained.

A stark example of not following least freedom was the Capital One breach of 2019: a misconfigured cloud permission granted a compromised component (a web program firewall) to obtain all data coming from an S3 storage space bucket, whereas in case that component got been limited to be able to only certain data, the breach impact would certainly have been a lot smaller​
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. Least privilege also applies with the signal level: when a module or microservice doesn't need certain access, it shouldn't have got it. Modern box orchestration and cloud IAM systems help it become easier to implement granular privileges, although it requires thoughtful design.

## Protection in Depth

This principle suggests that will security should always be implemented in overlapping layers, in order that when one layer fails, others still offer protection. In other words, don't rely on any single security manage; assume it can be bypassed, and have additional mitigations in place. Intended for an application, protection in depth may well mean: you validate inputs on the client side for usability, but an individual also validate these people on the server based (in case a great attacker bypasses the customer check). You protected the database powering an internal fire wall, but you also create code that checks user permissions prior to queries (assuming a great attacker might infringement the network). If using encryption, an individual might encrypt delicate data inside the data source, but also impose access controls in the application layer and monitor for unusual query patterns. Defense in depth is definitely like the levels of an onion – an attacker who gets by way of one layer ought to immediately face another. This approach counter tops the reality that no one defense is foolproof.

For example, assume an application depends on a net application firewall (WAF) to block SQL injection attempts. Defense comprehensive would dispute the application form should nevertheless use safe coding practices (like parameterized queries) to sterilize inputs, in case the WAF yearns for a novel harm. A real circumstance highlighting this was initially the truth of selected web shells or even injection attacks of which were not known by security filtration systems – the inner application controls after that served as the final backstop.

## Secure by Design and style and Secure by simply Default

These relevant principles emphasize making security an important consideration from typically the start of design and style, and choosing safe defaults. "Secure by simply design" means you want the system structures with security inside of mind – regarding instance, segregating sensitive components, using tested frameworks, and taking into consideration how each design and style decision could expose risk. "Secure by default" means if the system is implemented, it may default to the best settings, requiring deliberate motion to make this less secure (rather compared to the other method around).

An instance is default accounts policy: a safely designed application may ship without having standard admin password (forcing the installer to set a strong one) – because opposed to using a well-known default security password that users may well forget to change. Historically, many computer software packages were not safeguarded by default; they'd install with open up permissions or trial databases or debug modes active, in case an admin chosen not to lock them along, it left holes for attackers. With time, vendors learned to invert this: right now, databases and systems often come together with secure configurations out and about of the box (e. g., remote control access disabled, trial users removed), and even it's up to be able to the admin in order to loosen if completely needed.

For builders, secure defaults suggest choosing safe selection functions by default (e. g., arrears to parameterized inquiries, default to result encoding for net templates, etc. ). It also indicates fail safe – if a part fails, it should fail in the safe closed state quite than an insecure open state. For instance, if an authentication service times out there, a secure-by-default process would deny gain access to (fail closed) instead than allow that.

## Privacy by simply Design

Idea, strongly related to safety by design, offers gained prominence especially with laws like GDPR. It means that applications should be designed not only to be secure, but to regard users' privacy through the ground upward. Used, this may well involve data minimization (collecting only what is necessary), openness (users know exactly what data is collected), and giving users control over their info. While privacy is definitely a distinct website, it overlaps greatly with security: a person can't have privacy if you can't secure the personalized data you're liable for. A lot of the most severe data breaches (like those at credit score bureaus, health insurance providers, etc. ) usually are devastating not simply because of security failing but because they will violate the level of privacy of a lot of persons. Thus, modern software security often functions hand in hand with privacy factors.

## Threat Modeling

The practice throughout secure design is usually threat modeling – thinking like the attacker to assume what could make a mistake. During threat which, architects and programmers systematically go all the way through the type of a good application to recognize potential threats plus vulnerabilities. They inquire questions like: Precisely what are we building? What can move wrong? What will many of us do about it? One particular well-known methodology intended for threat modeling is definitely STRIDE, developed from Microsoft, which holds for six types of threats: Spoofing id, Tampering with files, Repudiation (deniability associated with actions), Information disclosure, Denial of support, and Elevation of privilege.

By jogging through each element of a system and considering STRIDE hazards, teams can reveal dangers that may possibly not be evident at first glance. For example, look at a simple online salaries application. Threat modeling might reveal that will: an attacker could spoof an employee's identity by questioning the session symbol (so we need to have strong randomness), could tamper with income values via a new vulnerable parameter (so we need insight validation and server-side checks), could carry out actions and later deny them (so we need good audit logs to stop repudiation), could make use of an information disclosure bug in the error message to glean sensitive details (so we want user-friendly but vague errors), might effort denial of service by submitting a new huge file or perhaps heavy query (so we need rate limiting and source quotas), or try out to elevate freedom by accessing managment functionality (so we all need robust entry control checks). Through this process, safety measures requirements and countermeasures become much clearer.

Threat modeling is ideally done early on in development (during the structure phase) so that security will be built in from the start, aligning with typically the "secure by design" philosophy. It's an evolving practice – modern threat which may additionally consider mistreatment cases (how can the system become misused beyond the particular intended threat model) and involve adversarial thinking exercises. We'll see its meaning again when talking about specific vulnerabilities in addition to how developers might foresee and stop them.

## Associated risk Management

Its not all protection issue is every bit as critical, and assets are always small. So another idea that permeates program security is risk management. This involves determining the possibilities of a threat along with the impact had been it to arise. Risk is normally informally considered as an event of these 2: a vulnerability that's easy to exploit plus would cause serious damage is substantial risk; one that's theoretical or might have minimal impact might be decrease risk. Organizations frequently perform risk examination to prioritize their particular security efforts. Regarding example, an online retailer might identify that this risk regarding credit card robbery (through SQL shot or XSS bringing about session hijacking) is incredibly high, and hence invest heavily in preventing those, although the risk of someone causing minor defacement in a less-used site might be approved or handled along with lower priority.

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

One touchable consequence of risk supervision in application security is the creation of a threat matrix or chance register where prospective threats are listed with their severity. This particular helps drive selections like which pests to fix 1st or where in order to allocate more tests effort. It's furthermore reflected in spot management: if the new vulnerability will be announced, teams can assess the threat to their application – is that exposed to that vulnerability, how serious is it – to determine how urgently to use the plot or workaround.

## Security vs. Usability vs. Cost

A discussion of rules wouldn't be full without acknowledging the real-world balancing work. Security measures can easily introduce friction or even cost. Strong authentication might mean even more steps for a consumer (like 2FA codes); encryption might slow down performance a little bit; extensive logging may raise storage fees. A principle to follow is to seek stability and proportionality – security should become commensurate with typically the value of what's being protected. Excessively burdensome security that will frustrates users could be counterproductive (users might find unsafe workarounds, intended for instance). The artwork of application safety is finding solutions that mitigate risks while preserving the good user experience and reasonable cost. Fortunately, with modern day techniques, many security measures can be made quite seamless – for illustration, single sign-on alternatives can improve the two security (fewer passwords) and usability, and even efficient cryptographic libraries make encryption scarcely noticeable regarding overall performance.

In summary, these kinds of fundamental principles – CIA, AAA, the very least privilege, defense detailed, secure by design/default, privacy considerations, menace modeling, and risk management – form typically the mental framework regarding any security-conscious doctor. They will show up repeatedly throughout information as we examine specific technologies and even scenarios. Whenever you are unsure concerning a security decision, coming back in order to these basics (e. g., "Am We protecting confidentiality? Are we validating sincerity? Are we reducing privileges? Can we include multiple layers of defense? ") could guide you to some more secure end result.

With these principles on mind, we are able to right now explore the particular risks and vulnerabilities that plague applications, in addition to how to guard against them.