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Web Attacks: Understanding the Threats
Welcome to the Web Attacks documentation section! This comprehensive collection covers 29 different attack types that threaten websites and web applications.
Whether you're a developer building secure applications, a business owner protecting your website, or just curious about cybersecurity, these guides break down complex attacks into simple, easy-to-understand concepts.
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What Are Web Attacks?
Web attacks are techniques hackers use to exploit vulnerabilities in websites and web applications. Think of them as different "break-in" methods criminals use to steal data, take over accounts, or damage systems.
Real-World Analogy: Just like a building can be broken into through the door, windows, ventilation system, or by tricking the security guard, websites can be attacked in many different ways. Each attack type uses a different "entry point."
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Our Documentation
We've created detailed guides for each major type of web attack. These guides are written in plain English with:
Simple explanations - No jargon, just clear language anyone can understand Real-world analogies - Compare technical concepts to everyday situations Practical examples - See exactly how attacks work Protection strategies - Learn how to defend against each attack Case studies - Real incidents that happened to major companies
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Available Attack Guides
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Core Injection Attacks
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SQL Injection Attacks
In One Sentence: Tricking a website's database into running malicious commands by "speaking its language."
Danger Level: CRITICAL - Can expose entire databases
What Hackers Can Do:
- Steal passwords and credit card numbers
- Delete or modify data
- Take over administrator accounts
- Access the entire server
Real Example: In 2008, hackers used SQL injection to steal 130 million credit card numbers from Heartland Payment Systems.
Who Should Read This:
- Developers building database-driven applications
- Business owners with customer data
- Anyone who wants to understand data breaches
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Cross-Site Scripting (XSS) Attacks
In One Sentence: Injecting malicious code into trusted websites that runs in victims' browsers.
Danger Level: HIGH - Can affect thousands of users automatically
What Hackers Can Do:
- Steal login sessions and hijack accounts
- Record everything you type (keylogger)
- Display fake login pages
- Redirect to malicious websites
- Perform actions as you (post, transfer money, etc.)
Real Example: In 2005, the Samy worm on MySpace infected over 1 million users in just 20 hours through stored XSS.
Who Should Read This:
- Web developers working with user input
- Social media platform developers
- Anyone building comment systems or forums
- Users who want to protect themselves online
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LDAP Injection
In One Sentence: Manipulating LDAP queries to bypass authentication or access unauthorized directory information.
Danger Level: HIGH - Can bypass authentication and expose directory data
What Hackers Can Do:
- Bypass authentication mechanisms
- Access unauthorized directory entries
- Extract sensitive organizational data
- Enumerate user accounts and groups
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XPath Injection
In One Sentence: Manipulating XPath queries to access or modify XML data stores.
Danger Level: HIGH - Can expose entire XML databases
What Hackers Can Do:
- Bypass authentication in XML-based systems
- Extract sensitive XML data
- Access unauthorized information
- Modify XML database content
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GraphQL Injection
In One Sentence: Exploiting GraphQL APIs through malicious queries, introspection abuse, or batching attacks.
Danger Level: HIGH - Can expose entire API schema and data
What Hackers Can Do:
- Discover hidden API endpoints via introspection
- Extract large amounts of data through deep queries
- Cause denial of service with nested queries
- Bypass rate limits with query batching
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Access Control & Authentication
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Broken Access Control (IDOR)
In One Sentence: Bypassing authorization checks to access other users' data or perform unauthorized actions.
Danger Level: CRITICAL - #1 in OWASP Top 10 2021
What Hackers Can Do:
- Access other users' private data
- Modify or delete others' information
- Escalate privileges to admin level
- View confidential business documents
Real Example: Facebook's 2018 breach exposed 50 million accounts through an access control flaw.
Who Should Read This:
- All web developers
- Security engineers
- Product managers
- Anyone handling user data
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Cross-Site Request Forgery (CSRF)
In One Sentence: Tricking users' browsers into performing unwanted actions on websites where they're already logged in.
Danger Level: HIGH - Can trigger unauthorized transactions and actions
What Hackers Can Do:
- Transfer money from victim's account
- Change account settings and passwords
- Make purchases using stored payment methods
- Post content as the victim
- Delete data
Real Example: In 2008, attackers used CSRF to transfer money from ING Direct customer accounts.
Who Should Read This:
- Web application developers
- Financial application developers
- Anyone building forms and actions
- Security professionals
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Session Fixation
In One Sentence: Forcing a user's session ID to a known value to hijack their session after login.
Danger Level: HIGH - Can lead to complete account takeover
What Hackers Can Do:
- Hijack user sessions after login
- Access user accounts without credentials
- Perform actions as the victim
- Steal sensitive data from sessions
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JWT Attacks
In One Sentence: Exploiting vulnerabilities in JSON Web Token implementation to forge tokens or bypass authentication.
Danger Level: CRITICAL - Can compromise entire authentication system
What Hackers Can Do:
- Forge authentication tokens
- Escalate privileges to admin
- Bypass signature verification
- Access any user account
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Server-Side Attacks
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Server-Side Request Forgery (SSRF)
In One Sentence: Tricking servers into making requests to internal systems or external services on behalf of the attacker.
Danger Level: CRITICAL - Can expose internal infrastructure
What Hackers Can Do:
- Access internal services not exposed to internet
- Read cloud metadata (AWS credentials)
- Scan internal network
- Bypass firewalls and access controls
- Steal sensitive configuration data
Real Example: Capital One breach (2019) - 100 million customers affected, $80 million fine.
Who Should Read This:
- Backend developers
- Cloud engineers
- DevOps professionals
- API developers
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XML External Entity (XXE)
In One Sentence: Exploiting XML parsers to access files, perform SSRF, or cause denial of service.
Danger Level: HIGH - Can lead to data exposure and system compromise
What Hackers Can Do:
- Read local files (/etc/passwd, configuration files)
- Perform SSRF attacks via XML
- Cause denial of service (billion laughs attack)
- Execute remote code in some cases
Real Example: Facebook XXE vulnerability allowed reading arbitrary files from their servers.
Who Should Read This:
- Developers working with XML
- API developers (especially SOAP)
- Security researchers
- Backend engineers
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Server-Side Template Injection (SSTI)
In One Sentence: Injecting malicious code into template engines to achieve remote code execution.
Danger Level: CRITICAL - Direct path to RCE
What Hackers Can Do:
- Execute arbitrary code on server
- Read sensitive files and environment variables
- Take complete control of the application
- Access databases and internal systems
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Insecure Deserialization
In One Sentence: Exploiting the process of converting serialized data back into objects to execute malicious code.
Danger Level: CRITICAL - Often leads to Remote Code Execution (RCE)
What Hackers Can Do:
- Execute arbitrary code on the server
- Take complete control of the system
- Install backdoors and malware
- Access all server data
- Create admin accounts
Real Example: Equifax breach (2017) - 147 million affected, $700+ million in costs.
Who Should Read This:
- All backend developers
- Java, Python, PHP developers
- Security architects
- DevOps engineers
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Prototype Pollution
In One Sentence: Manipulating JavaScript object prototypes to inject properties that affect application behavior.
Danger Level: HIGH-CRITICAL - Can lead to XSS, DoS, or RCE
What Hackers Can Do:
- Modify application logic and behavior
- Bypass security controls
- Achieve XSS or authentication bypass
- Cause denial of service
Read Prototype Pollution Guide
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Authentication & Session Management
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Broken Authentication
In One Sentence: Exploiting weaknesses in login systems to compromise user accounts.
Danger Level: CRITICAL - #2 in OWASP Top 10, complete account takeover
What Hackers Can Do:
- Take over user accounts
- Access stored payment information
- Impersonate legitimate users
- Bypass multi-factor authentication
- Gain admin privileges
Real Example: Ring Camera credential stuffing (2019) - attackers accessed home security cameras.
Who Should Read This:
- All developers
- Security teams
- Identity management professionals
- Product managers
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Configuration & Infrastructure
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Security Misconfiguration
In One Sentence: Failing to properly configure security settings, leaving applications vulnerable.
Danger Level: HIGH - #5 in OWASP Top 10, extremely common
What Hackers Can Do:
- Access admin panels with default passwords
- Read sensitive configuration files
- Exploit known vulnerabilities in outdated software
- Access internal services
- Enumerate system information
Real Example: Capital One AWS misconfiguration (2019) - 100 million customers affected.
Who Should Read This:
- System administrators
- DevOps engineers
- Cloud architects
- All developers
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CORS Misconfiguration
In One Sentence: Incorrectly configured Cross-Origin Resource Sharing policies allowing unauthorized cross-domain access.
Danger Level: HIGH - Can expose sensitive data to unauthorized domains
What Hackers Can Do:
- Read sensitive data from APIs
- Steal authentication tokens
- Access private user information
- Perform actions on behalf of victims
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Subdomain Takeover
In One Sentence: Claiming abandoned subdomains to serve malicious content under a trusted domain.
Danger Level: MEDIUM-HIGH - Reputation damage and phishing risks
What Hackers Can Do:
- Host phishing pages on trusted domains
- Steal cookies from parent domain
- Damage brand reputation
- Distribute malware
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Network & Protocol Attacks
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Man-in-the-Middle (MitM)
In One Sentence: Intercepting communications between two parties to eavesdrop or manipulate data.
Danger Level: CRITICAL - Can steal passwords and sensitive data in real-time
What Hackers Can Do:
- Steal login credentials and session tokens
- Read encrypted communications
- Modify data in transit
- Inject malicious code
- Redirect to phishing sites
Real Example: Lenovo Superfish (2015) - Pre-installed malware intercepted HTTPS traffic on all devices.
Who Should Read This:
- Network engineers
- Mobile app developers
- Security professionals
- End users for awareness
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HTTP Request Smuggling
In One Sentence: Exploiting differences in how front-end and back-end servers parse HTTP requests.
Danger Level: CRITICAL - Can bypass security controls and poison caches
What Hackers Can Do:
- Bypass security controls and WAFs
- Poison web caches
- Hijack other users' requests
- Access unauthorized resources
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Web Cache Poisoning
In One Sentence: Manipulating cached content to serve malicious responses to multiple users.
Danger Level: HIGH - Can affect thousands of users
What Hackers Can Do:
- Inject XSS into cached pages
- Redirect users to malicious sites
- Serve malicious content from trusted domains
- Persist attacks across multiple victims
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Host Header Injection
In One Sentence: Manipulating the HTTP Host header to exploit server-side vulnerabilities.
Danger Level: MEDIUM-HIGH - Can lead to cache poisoning and password reset poisoning
What Hackers Can Do:
- Poison password reset emails
- Perform cache poisoning attacks
- Bypass authentication
- Conduct SSRF attacks
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CRLF Injection
In One Sentence: Injecting Carriage Return and Line Feed characters to manipulate HTTP headers and responses.
Danger Level: MEDIUM-HIGH - Can lead to XSS, cache poisoning, and session hijacking
What Hackers Can Do:
- Inject malicious HTTP headers
- Split responses for XSS attacks
- Poison web caches
- Perform log injection
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File System & Command Attacks
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Directory Traversal (Path Traversal)
In One Sentence: Manipulating file paths to access files outside the intended directory.
Danger Level: HIGH - Can expose sensitive configuration files and source code
What Hackers Can Do:
- Read system files (/etc/passwd)
- Access configuration files with database passwords
- View application source code
- Read SSH private keys
- Access log files
Real Example: Zip Slip vulnerability (2018) - Affected thousands of projects, allowing file extraction outside intended directories.
Who Should Read This:
- All web developers
- DevOps engineers
- Security professionals
- Anyone handling file uploads or downloads
Read Directory Traversal Guide
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OS Command Injection
In One Sentence: Forcing applications to execute arbitrary operating system commands.
Danger Level: CRITICAL - Complete system compromise and RCE
What Hackers Can Do:
- Execute any command on the server
- Read/delete/modify any file
- Install backdoors and malware
- Steal sensitive data
- Take complete control of the system
Real Example: Shellshock Bash vulnerability (2014) - Millions of servers affected, used in botnets and ransomware.
Who Should Read This:
- Backend developers
- System administrators
- DevOps engineers
- Security professionals
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Clickjacking (UI Redressing)
In One Sentence: Tricking users into clicking hidden elements by layering invisible iframes.
Danger Level: MEDIUM-HIGH - Can steal clicks for unauthorized actions
What Hackers Can Do:
- Make users like/follow pages unknowingly
- Trigger unauthorized transactions
- Enable webcam/microphone without consent
- Change account settings
- Grant app permissions
Real Example: Twitter "Don't Click" worm (2009) - Viral clickjacking spreading through retweets.
Who Should Read This:
- Web developers
- Frontend engineers
- Security professionals
- Social media platform developers
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File Inclusion (LFI/RFI)
In One Sentence: Tricking applications into including malicious local or remote files.
Danger Level: CRITICAL - Can lead to complete server compromise
What Hackers Can Do:
- Execute arbitrary code (Remote Code Execution)
- Read sensitive files and source code
- Access configuration and credentials
- Upload and execute malicious scripts
- Take over the entire server
Real Example: WordPress core LFI (2015) - Millions of sites affected, configuration files exposed.
Who Should Read This:
- PHP developers (most common)
- All web developers
- Security engineers
- Penetration testers
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Client-Side & UI Attacks
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Clickjacking (UI Redressing)
In One Sentence: Tricking users into clicking hidden elements by layering invisible iframes.
Danger Level: MEDIUM-HIGH - Can steal clicks for unauthorized actions
What Hackers Can Do:
- Make users like/follow pages unknowingly
- Trigger unauthorized transactions
- Enable webcam/microphone without consent
- Change account settings
- Grant app permissions
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DOM Clobbering
In One Sentence: Exploiting HTML element naming to override JavaScript variables and manipulate DOM properties.
Danger Level: MEDIUM - Can bypass security filters and cause XSS
What Hackers Can Do:
- Override JavaScript variables
- Bypass XSS filters and sanitizers
- Manipulate application logic
- Cause unexpected behavior
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HTML Injection
In One Sentence: Injecting malicious HTML into web pages without executing JavaScript.
Danger Level: MEDIUM - Can deface sites and perform phishing
What Hackers Can Do:
- Deface websites
- Create fake login forms
- Spread misinformation
- Phishing attacks
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Open Redirect
In One Sentence: Exploiting redirect functionality to send users to malicious external sites.
Danger Level: MEDIUM - Commonly used in phishing campaigns
What Hackers Can Do:
- Redirect to phishing sites
- Distribute malware
- Steal OAuth tokens
- Abuse trusted domain reputation
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Advanced Application Logic Attacks
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Race Conditions
In One Sentence: Exploiting timing windows between operations to cause unintended application behavior.
Danger Level: MEDIUM-HIGH - Can bypass limits and cause financial loss
What Hackers Can Do:
- Bypass payment systems
- Redeem vouchers multiple times
- Withdraw money multiple times
- Bypass rate limiting
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Mass Assignment
In One Sentence: Manipulating request parameters to modify unintended object properties.
Danger Level: HIGH - Can lead to privilege escalation
What Hackers Can Do:
- Escalate privileges to admin
- Modify protected fields
- Bypass payment amounts
- Change account roles
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Quick Comparison: Which Attack is Which?
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Protection Principles (Universal Defenses)
While each attack is different, some security principles protect against multiple threats:
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1. Never Trust User Input
Simple Rule: Treat everything users type as potentially malicious.
Real-World Analogy: Like a security checkpoint at an airport - check everything, even from "trusted" passengers.
How to Apply:
- Validate all input (only allow expected characters)
- Sanitize/escape special characters
- Use allowlists, not blocklists
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2. Principle of Least Privilege
Simple Rule: Give users and systems only the minimum access they need.
Real-World Analogy: A janitor doesn't need keys to the bank vault - give access only where necessary.
How to Apply:
- Database accounts should have minimal permissions
- Users should only access their own data
- Admin accounts should be separate from regular accounts
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3. Defense in Depth (Layers of Security)
Simple Rule: Use multiple layers of protection, not just one.
Real-World Analogy: A castle has a moat, walls, gates, and guards - if one fails, others still protect.
How to Apply:
- Input validation + output encoding + WAF
- Authentication + authorization + logging
- Client-side + server-side validation
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4. Keep Software Updated
Simple Rule: Always use the latest versions of frameworks and libraries.
Real-World Analogy: Like patching a hole in your roof - if you know about a vulnerability, fix it immediately!
How to Apply:
- Regular updates of dependencies
- Security patch management
- Monitor security advisories
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For Developers: Quick Security Checklist
Before deploying any web application:
- All user input is validated and sanitized
- Output is properly encoded based on context
- Using parameterized queries (not string concatenation)
- Content Security Policy (CSP) is implemented
- Security headers are configured correctly
- Cookies have HttpOnly and Secure flags
- Regular security testing is performed
- Error messages don't reveal sensitive information
- Logging and monitoring are in place
- Third-party libraries are up to date
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For Business Owners: Why This Matters
The Cost of Attacks:
Beyond Money:
- Loss of customer trust (can take years to rebuild)
- Legal liabilities and class-action lawsuits
- Regulatory fines (GDPR up to 4% of global revenue, CCPA up to $7,500 per violation)
- Business disruption and downtime
- Reputational damage that lasts years
- Loss of competitive advantage (stolen IP)
- Executive resignations (Equifax CEO resigned)
- Stock price impacts (immediate drops of 10-30% common)
Protection is Cheaper Than Recovery:
- Average cost of a data breach: $4.45 million (IBM 2023)
- Average security investment to prevent breach: $100,000-500,000
- ROI of prevention: 10-40x cheaper than remediation
What happens during a breach:
- Incident response costs ($500K-$2M)
- Forensic investigation ($200K-$1M)
- Legal fees and settlements ($1M-$100M+)
- Regulatory fines (varies by jurisdiction)
- Credit monitoring for affected customers ($5-20 per person)
- PR and crisis management ($100K-$1M)
- System upgrades and remediation ($500K-$5M)
- Lost business during downtime
- Customer churn (average 25-30% after major breach)
- Increased insurance premiums
Prevention is not just cheaper - it's essential for survival. 65% of small businesses that suffer a major breach go out of business within 6 months.
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For Regular Users: How to Stay Safe
While developers need to build secure websites, you can also protect yourself:
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General Safety Tips
TIP Use unique passwords for each website - if one gets hacked, others stay safe TIP Enable two-factor authentication (2FA) everywhere possible TIP Be suspicious of links - hover to check the real URL before clicking TIP Use a modern browser - Chrome, Firefox, Edge have built-in protections TIP Install ad blockers - Many attacks spread through malicious ads TIP Watch for warning signs - Strange popups, unexpected redirects, or weird behavior
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Red Flags (Signs of an Attack)
Website suddenly looks different or shows errors Unexpected login prompts or password reset requests Strange browser popups or warnings URLs with lots of symbols or weird characters Emails with shortened URLs (bit.ly, etc.) from unknown sources Website performance suddenly degrades
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Learning Path
If you're new to web security:
Start with the fundamentals:
- SQL Injection - Understand how database attacks work
- XSS - Learn about browser-based attacks
- Broken Authentication - How login systems get compromised
Progress to access control issues:
- Broken Access Control - Authorization flaws (OWASP #1)
- CSRF - Session exploitation attacks
Learn about server-side attacks:
- SSRF - Tricking servers into making malicious requests
- XXE - XML parsing vulnerabilities
- Insecure Deserialization - Remote code execution risks
Master configuration and network security:
- Security Misconfiguration - Common setup mistakes
- Man-in-the-Middle - Network interception attacks
Explore file system and command injection attacks:
- Directory Traversal - File path manipulation
- OS Command Injection - System command execution
- File Inclusion (LFI/RFI) - Dynamic file loading exploits
Explore advanced injection techniques:
- LDAP Injection - Directory service attacks
- XPath Injection - XML query manipulation
- GraphQL Injection - API exploitation
- SSTI - Template engine exploitation
Master session and token security:
- Session Fixation - Session hijacking techniques
- JWT Attacks - Token forgery and manipulation
Learn network and protocol attacks:
- HTTP Request Smuggling - Request parsing exploits
- Web Cache Poisoning - Cache manipulation
- Host Header Injection - Header manipulation
- CRLF Injection - HTTP response splitting
Understand client-side attacks:
- Clickjacking - Invisible iframe overlay attacks
- DOM Clobbering - JavaScript variable manipulation
- HTML Injection - Non-script content injection
- Open Redirect - URL redirection exploits
Study configuration and infrastructure issues:
- CORS Misconfiguration - Cross-origin policy flaws
- Subdomain Takeover - DNS and service vulnerabilities
- Prototype Pollution - JavaScript object manipulation
Master advanced logic attacks:
- Race Conditions - Timing-based exploits
- Mass Assignment - Parameter manipulation
Practice and experiment:
- Set up test environments to safely experiment
- Use vulnerable applications (DVWA, WebGoat, bWAPP)
- Try the code examples in each guide
If you're a developer:
- Read all attack guides thoroughly
- Review your existing code for vulnerabilities
- Implement the prevention techniques for each attack type
- Use the testing tools mentioned in each guide
- Integrate security into your development workflow:
- Use static analysis tools (SAST)
- Implement automated security testing
- Conduct code reviews with security focus
- Stay updated with OWASP guidelines and security bulletins
If you're a business owner:
- Understand the risks and real-world costs (see case studies in each guide)
- Share these guides with your development team
- Implement the protection checklists from all guides
- Consider professional security audits covering all attack types
- Create an incident response plan
- Invest in security training for your team
- Implement monitoring and logging for attack detection
- Consider managed security services like Layerd AI Guardian Proxy
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Additional Resources
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Security Organizations
- OWASP (Open Web Application Security Project) - Free resources and tools
- CWE (Common Weakness Enumeration) - Database of software weaknesses
- NIST - National Institute of Standards and Technology
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Practice Safely
- OWASP WebGoat - Practice hacking in a safe, legal environment
- Hack The Box - Legal penetration testing practice
- DVWA (Damn Vulnerable Web Application) - Intentionally vulnerable app for learning
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Stay Informed
- Subscribe to security newsletters
- Follow OWASP and security researchers
- Monitor vulnerability databases
- Join cybersecurity communities
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Get Protected with Layerd AI
All 29 attack types documented here can be automatically detected and blocked in real-time with Layerd AI Guardian Proxy.
Comprehensive Protection Against All Attack Types:
SQL Injection Protection - Pattern matching and semantic analysis of database queries
XSS Prevention - Content Security Policy enforcement and automatic script sanitization
Access Control Enforcement - Real-time authorization checks and IDOR detection
CSRF Protection - Token validation and SameSite cookie enforcement
SSRF Prevention - URL validation and internal network protection
XXE Mitigation - XML parser hardening and external entity blocking
Deserialization Security - Object type validation and signature verification
Authentication Hardening - Rate limiting, credential stuffing detection, and MFA enforcement
Configuration Monitoring - Automatic security header injection and misconfiguration alerts
Network Security - TLS enforcement, certificate validation, and MitM detection
Path Traversal Prevention - File path validation and ../sequence blocking
Command Injection Defense - Shell command pattern detection and input sanitization
Clickjacking Protection - Automatic X-Frame-Options and CSP frame-ancestors headers
File Inclusion Blocking - PHP wrapper detection and remote file inclusion prevention
Injection Attack Defense - LDAP, XPath, and GraphQL query validation
Session Security - Session fixation and JWT vulnerability detection
Protocol Attack Prevention - HTTP smuggling, cache poisoning, and CRLF detection
Client-Side Protection - DOM clobbering, HTML injection, and open redirect blocking
Logic Attack Detection - Race condition and mass assignment prevention
Additional Features:
- AI-powered threat detection - Machine learning identifies zero-day attacks
- Detailed attack analytics - Real-time dashboards and historical analysis
- Line-rate performance - Zero latency impact on legitimate traffic
- 24/7 monitoring - Continuous threat intelligence updates
- Comprehensive logging - Full audit trail for compliance (GDPR, PCI-DSS, SOC2)
- Easy deployment - Works with any application stack, no code changes required
Learn more about Layerd AI Protection →
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Questions or Feedback?
Found something confusing? Have suggestions for improvement? We want these guides to be as clear and helpful as possible.
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Last updated: November 2025