100 Tips from Expert Penetration Testers for Developers

Protecting the applications from malicious threats has become the highest priority for developers and organizations, as software vulnerabilities and cyber threats are prevalent in today’s digital world.

At IARM Information Security, we have an expert penetration testing team with a proven track record of securing over 2000+ business applications. We are committed to sharing our extensive knowledge repository through this guide. These tips will help you with the knowledge of the best security practices and will enhance your code, defending your applications from cyber attacks.

  1. Authorization: Implement strong authentication mechanisms, such as multi-factor authentication (MFA), and enforce proper authorization to ensure that only authorized users can access specific functionalities or data.
  2. Secure Communication: Utilize secure communication protocols, such as HTTPS, SSL/TLS, and implement encryption techniques to protect data transmission between the application and clients or external services.
  3. Input Validation and Sanitization: Validate and sanitize all user inputs to prevent malicious data from being processed, which can lead to security vulnerabilities like code injection or command injection attacks. Enable input/output encoding and output validation techniques to prevent XSS attacks.
  4. Session Management: Implement secure session management techniques, including session timeouts, secure session storage, and protection against session fixation attacks.
  5. Secure Configuration Management: Ensure that the application’s configuration settings, such as database credentials, API keys, and access control settings, are securely managed and protected from unauthorized access.
  6. Regular Patching and Updates: Stay up to date with security patches and updates for all components and libraries used in the application, including the underlying operating system, web server, application framework, and third-party dependencies.
  7. Secure Data Storage: Implement strong encryption techniques to protect sensitive data at rest, such as passwords, credit card information, or personally identifiable information (PII). Avoid storing unnecessary sensitive data.
  8. Principle of Least Privilege: Implement the principle of least privilege, granting users and processes only the minimum privileges necessary to perform their tasks, reducing the potential impact of a security breach.
  9. Secure File Handling: Validate file uploads for size, type, and content to prevent arbitrary file uploads that could lead to security vulnerabilities like code execution or information disclosure.
  10. Secure Password Storage: Store passwords using strong hashing algorithms such as bcrypt or Argon2 along with salts, to protect user credentials in case of a data breach.
  11. Secure Third-Party Integration: Conduct thorough security assessments of third-party libraries, APIs, and services, before integration and ensuring they adhere to secure coding practices and also have a good security track record.
  12. Secure Mobile Development: Apply secure coding practices specific to mobile platforms, including input validation, secure storage, proper use of permissions, and protection against reverse engineering. Boost your mobile security today!
  13. Secure API Development: Implement authentication, authorization, input validation, and rate limiting mechanisms for APIs to prevent unauthorized access, data exposure and denial-of-service (DoS) attacks.
  14. Secure Data Transmission: Encrypt sensitive data during transmission using protocols like SSL/TLS or message-level encryption to protect against eavesdropping and man-in-the-middle attacks.
  15. Cross-Site Request Forgery (CSRF) Prevention: Implement CSRF protection mechanisms such as anti-CSRF tokens and same-site cookies to prevent unauthorized actions performed on behalf of authenticated users.
  16. Security Headers: Implement security headers, such as Content Security Policy (CSP), HTTP Strict Transport Security (HSTS) and X-XSS-Protection to enhance the security posture of the application’s web server.
  17. Secure Configuration Files: Protect sensitive information stored in configuration files such as database credentials or API keys by storing them outside the web root directory or using encryption.
  18. Secure File Permissions: Set appropriate file permissions on application files ensuring that only necessary users or processes have read, write or execute permissions to prevent unauthorized access or modification.
  19. Secure Error Messages: Avoid displaying detailed error messages to users, which can reveal sensitive information or assist attackers in exploiting vulnerabilities. Provide generic error messages and log detailed errors securely for debugging purposes.
  20. Secure Cross-Origin Resource Sharing (CORS): Implement proper CORS settings to restrict which domains can access the application’s resources, preventing unauthorized cross-origin requests.
  21. Secure Cryptography Implementation: Use well-established cryptographic libraries and algorithms for encryption, hashing, and digital signatures, following industry best practices and avoiding homegrown or weak encryption methods.
  22. Secure Two-Factor Authentication (2FA): Implement 2FA using secure methods such as Time-based One-Time Passwords (TOTP) or Universal Second Factor (U2F) to provide an additional layer of security for user authentication.
  23. Secure Object Serialization: Implement secure object serialization practices, restricting deserialization to trusted sources and mitigate deserialization vulnerabilities.
  24. Secure Application Dependencies: Regularly update and patch all third-party libraries, frameworks, and dependencies used in the application to mitigate known security vulnerabilities and exploit vectors.
  25. Secure Logout Functionality: Implement secure logout mechanisms to invalidate user sessions, clear session data, and prevent session fixation attacks.
  26. Secure Account Recovery: Implement secure account recovery mechanisms, such as password reset workflows, using methods like email verification or security questions, with appropriate validation and protection against abuse.
  27. Secure Data Backup and Data Recovery: Implement secure backup and recovery procedures to ensure that critical data is regularly backed up, encrypted during storage, and can be restored securely in case of data loss or system compromise.
  28. Secure Logging and Auditing: Implement logging of security-relevant events, including authentication failures, access control changes, and critical system operations, to enable effective auditing and incident response.
  29. Secure Cross-Site Script Inclusion (XSSI) Prevention: Validate and sanitize data used for dynamic script inclusion to prevent XSSI attacks, ensuring that only trusted sources are allowed for script inclusion.
  30. Secure Server-Side Request Forgery (SSRF) Prevention: Validate and sanitize all user-supplied URLs to prevent SSRF attacks, ensuring that requests are limited to authorized and trusted resources.
  31. Implement Server-Side Input Validation: Perform input validation on the server-side to ensure that data received from clients is properly validated and sanitized. This helps prevent the inclusion of malicious scripts from user inputs.
  32. Secure Change Management: Implement a robust change management process to track and control changes to the application’s codebase, configuration, and infrastructure, ensuring that security-related changes are properly reviewed and tested.
  33. Secure API Key and Secret Management: Protect API keys and other sensitive information used for authentication or authorization, using secure storage mechanisms, such as environment variables or secure key stores.
  34. Secure Administration Interfaces: Implement strong authentication, access controls, and secure communication for administrative interfaces, protecting against unauthorized access and administrative account compromise.
  35. Secure HTTP Security Headers: Implement additional security headers like X-Content-Type-Options, X-Frame-Options, and X-Content-Security-Policy, to further enhance the security posture of the application.
  36. Secure Email Handling: Implement secure email handling practices, including input validation, sanitization, and protection against email header injection and email spoofing attacks.
  37. Secure Time and Date Management: Use trusted time sources, implement proper time zone handling, and protect against time-based attacks, such as replay attacks or timing attacks.
  38. Secure Random Number Generation: Use secure random number generators provided by the operating system or cryptographic libraries to generate random values for security-critical operations, such as session tokens or cryptographic keys.
  39. Implement Rate Limiting and Anti-Automation Measures: Implement rate limiting mechanisms and anti-automation measures to prevent abuse, DoS attacks, unauthorized API access, and automated attacks, including cross-site script inclusion attempts. These safeguards enforce and monitor usage limits, ensuring protection against abusive behaviors.
  40. Secure Single Sign-On (SSO): Implement secure SSO mechanisms, such as SAML or OAuth, using industry-standard protocols and secure implementations to enable seamless and secure authentication across multiple applications.
  41. Secure IoT Device Integration: If your application interacts with IoT devices, follow secure coding practices, authenticate and authorize device connections, encrypt communication and regularly update firmware to mitigate potential vulnerabilities.
  42. Secure Remote Access: If your application provides remote access capabilities, implement secure remote access mechanisms such as VPNs or secure remote desktop protocols and enforce strong authentication and encryption.
  43. Secure Memory Management: Implement secure memory management practices to prevent memory-related vulnerabilities, such as buffer overflows or memory leaks by properly allocating, using, and freeing memory resources.
  44. Secure Geolocation Services: If your application utilizes geolocation services, ensure that user location data is handled securely, and implement appropriate privacy controls to protect user identities and sensitive location information.
  45. Secure Integration with Payment Gateways: If your application processes financial transactions and  integrates with trusted and compliant payment gateways, following industry security standards such as PCI DSS to protect sensitive payment information.
  46. Secure Multi-Tenancy: If your application supports multi-tenancy, implement proper data isolation and access controls to prevent unauthorized access or data leakage between tenants.
  47. Secure In-App Purchases: If your application supports in-app purchases, implement secure payment mechanisms, verify purchase integrity on the server-side, and protect against fraudulent transactions.
  48. Secure Push Notifications: If your application sends push notifications, implement secure methods for authentication and authorization, ensuring that only authorized parties can send notifications to users.
  49. Secure Code Obfuscation: Apply code obfuscation techniques to make it harder for attackers to reverse engineer and understand the application’s code, protecting sensitive algorithms, keys, or intellectual property.     
  50. Secure Integration with Social Media Platforms: If your application integrates with social media platforms, follow secure coding practices, protect user data, and enforce proper authentication and authorization mechanisms.
  51. Secure Cloud Infrastructure: If your application is hosted in the cloud, configure security groups, network access controls, and implement secure authentication and authorization mechanisms to protect against unauthorized access and data breaches.
  52. Secure Mobile App Distribution: Implement secure distribution channels, such as official app stores or mobile device management (MDM) platforms, to ensure that users download authentic and untampered versions of your mobile application.
  53. Secure Remote Code Execution: If your application allows remote code execution, establish strict controls and verification mechanisms to prevent the execution of unauthorized or malicious code.
  54. Secure Integration with Third-Party Services: If your application integrates with third-party services, carefully review their security practices, conduct security assessments, and enforce secure communication and data handling practices.
  55. Secure Peer-to-Peer Communication: If your application facilitates peer-to-peer communication, implement secure encryption, authentication, and data validation mechanisms to protect against eavesdropping and data tampering.
  56. Secure Remote Wipe/Deactivation: If your application involves remote wipe or deactivation functionality, ensure that proper authentication and authorization controls are in place to prevent unauthorized or malicious use.
  57. Secure Firmware Updates: If your application relies on firmware updates for devices or components, implement secure firmware distribution, verification, and installation procedures to prevent unauthorized or compromised updates.
  58. Secure Integration with Cloud Storage: If your application integrates with cloud storage services, enforce secure authentication, access controls, and encryption to protect data stored in the cloud.
  59. Secure Integration with Blockchain Technology: If your application utilizes blockchain technology, follow secure coding practices, protect private keys and smart contracts, and conduct thorough security assessments to mitigate potential vulnerabilities.
  60. Secure Integration with Machine Learning Models: If your application incorporates machine learning models, implement secure methods for data handling, model training, and protection against adversarial attacks.
  61. Secure Integration with Voice Recognition/Command Systems: If your application integrates with voice recognition or command systems, implement secure voice authentication and protect against spoofing or unauthorized access.
  62. Secure Integration with Biometric Authentication: If your application incorporates biometric authentication, follow industry best practices, protect biometric data, and implement secure storage and matching algorithms.
  63. Secure Integration with Augmented/Virtual Reality (AR/VR): If your application includes AR/VR functionality, consider security measures to protect user privacy, prevent data leakage, and ensure the integrity of virtual environments.
  64. Secure Integration with Wearable Devices: If your application interacts with wearable devices, implement secure communication protocols, authentication mechanisms, and privacy controls to protect user data and ensure device integrity.
  65. Secure Integration with Voice over IP (VoIP) Systems: If your application incorporates VoIP functionality, implement secure protocols, encrypt voice communication, and protect against eavesdropping or call interception.
  66. Secure Integration with Digital Rights Management (DRM) Systems: If your application involves DRM systems, follow secure implementation practices, protect cryptographic keys, and prevent unauthorized access or tampering with protected content.
  67. Secure Integration with Content Delivery Networks (CDNs): If your application utilizes CDNs, implement secure communication channels, verify CDN authenticity, and protect against malicious content injection or unauthorized CDN modifications.
  68. Secure Integration with Hardware Security Modules (HSMs): If your application relies on HSMs for key management or cryptographic operations, follow HSM security guidelines, protect HSM access, and enforce secure key handling practices.
  69. Secure Integration with Data Loss Prevention (DLP) Systems: If your application incorporates DLP systems, implement secure data classification, enforce data handling policies, and protect against unauthorized data exfiltration or leakage.
  70. Secure Endpoint Protection: Implement endpoint protection measures, such as antivirus software, host-based intrusion detection/prevention systems, and regular security updates, to protect against malware and unauthorized access to endpoints.
  71. Secure Integration with Intrusion Detection/Prevention Systems (IDS/IPS): If your application interacts with IDS/IPS systems, ensure secure communication, authenticate system connections, and prevent evasion or bypassing of security controls.
  72. Secure Integration with Security Information and Event Management (SIEM) Systems: If your application integrates with SIEM systems, follow secure logging practices, implement secure communication channels, and protect against log tampering or manipulation. Protect Your App with SIEM Integration Now
  73. Secure Integration with Vulnerability Scanners: If your application interfaces with vulnerability scanners or security assessment tools, ensure secure data transmission, validate scanner authenticity, and protect against false positives or information leakage. You can also outsource vulnerability assessment and penetration testing services to identify  effective detection.
  74. Secure Incident Response Plan: Develop and regularly update an incident response plan that outlines the steps to be taken in case of a security incident, including incident identification, containment, eradication, and recovery.
  75. Secure Integration with Incident Response Systems: If your application integrates with incident response systems, establish secure communication channels, authenticate system connections, and protect against unauthorized access or manipulation of incident data.
  76. Secure Integration with Certificate Authorities (CAs): If your application relies on digital certificates for authentication or encryption, follow secure certificate management practices, validate CA authenticity, and protect private keys.
  77. Secure Integration with Continuous Integration/Continuous Deployment (CI/CD) Systems: If your application uses CI/CD pipelines, follow secure CI/CD practices, enforce access controls, and protect sensitive code or configuration information.
  78. Regular Security Audits and Assessments: Conduct regular security audits, assessments, and penetration testing to identify vulnerabilities, validate security controls, and ensure ongoing security of the application.
  79. Secure Integration with Web Application Firewalls (WAFs): If your application interacts with WAFs, configure and customize WAF rules to protect against common web application attacks, such as SQL injection or cross-site scripting.
  80. Secure Integration with Threat Intelligence Platforms: If your application incorporates threat intelligence platforms, leverage real-time threat feeds, implement secure API integration, and utilize threat intelligence data to enhance security controls.
  81. Secure Integration with Data Encryption/Tokenization Services: If your application handles sensitive data, leverage data encryption or tokenization services to protect data at rest and in transit, ensuring proper key management and access controls.
  82. Secure Data Masking/Anonymization: If your application requires data masking or anonymization, implement secure techniques to obfuscate sensitive information, protecting privacy and reducing the risk of data exposure.
  83. Secure Voice and Video Recording: If your application involves voice or video recording, ensure compliance with privacy regulations, protect recorded data from unauthorized access, and securely handle storage and retention of recorded content.
  84. Secure User Activity Monitoring: Implement user activity monitoring mechanisms to detect suspicious behavior, such as privilege escalation or unusual access patterns, and promptly respond to potential security incidents.
  85. Secure Integration with Identity and Access Management (IAM) Systems: If your application integrates with IAM systems, enforce strong authentication, role-based access controls, and centralized user management to ensure proper user identity verification and authorization.
  86. Secure Data Segregation: If your application handles multiple types of data or sensitive information, implement proper data segregation mechanisms to prevent unauthorized access or leakage between different data categories or user groups.
  87. Secure Supply Chain Management: Ensure the security of the entire software supply chain, from development to deployment, by vetting and monitoring vendors, using secure distribution channels, and implementing secure code signing practices.
  88. Secure Network Configuration: Implement secure network configurations, including firewall rules, network segmentation, and intrusion detection/prevention systems, to protect the application from network-based attacks and unauthorized access.
  89. Secure Data Retention and Disposal: Define proper data retention policies, securely dispose of data when no longer needed, and follow industry best practices for data sanitization to prevent unauthorized access to sensitive information.
  90. Secure Remote Code Review: If code review is conducted remotely, ensure secure communication channels, protect source code during transit, and enforce strict access controls to maintain the confidentiality and integrity of the codebase.
  91. Security Awareness Training: Provide regular security awareness training to all personnel involved in the application’s development, deployment, and maintenance, promoting a security-conscious culture and educating them about common threats and best practices. Secure Your Business Now with leading Cybersecurity Company!
  92. Strict Content-Type Validation: Validate the Content-Type header of the response to ensure it matches the expected type for the requested resource. This helps prevent the inclusion of scripts from unintended sources.
  93. Implement Content Security Policy (CSP): Utilize Content Security Policy to define a whitelist of trusted sources for scripts, stylesheets, and other resources. This restricts the inclusion of external scripts to only trusted domains.
  94. Use Subresource Integrity (SRI): Apply Subresource Integrity to ensure the integrity and authenticity of externally hosted scripts. SRI allows the browser to verify that the fetched script matches the expected cryptographic hash, mitigating the risk of script tampering.
  95. Use Strict Mode: Enable strict mode in JavaScript to enforce better coding practices and avoid vulnerabilities that can be exploited for script inclusion attacks.
  96. Limit User-Generated Content Rendering: Limit the rendering of user-generated content within the application to prevent the execution of potentially malicious scripts. Sanitize and validate the content before rendering it in web pages.
  97. Implement Content-Type Sniffing Protection: Set the X-Content-Type-Options header to “nosniff” to prevent browsers from performing content-type sniffing. This helps prevent the interpretation of responses as different content types, reducing the risk of script inclusion.
  98. Use Security-focused Libraries and Frameworks: Utilize well-established and security-focused libraries and frameworks for developing your application. These frameworks often have built-in security features and mechanisms to prevent common vulnerabilities, including cross-site script inclusion.
  99. Implement Clickjacking Protection: Employ techniques such as X-Frame-Options or Content-Security-Policy frame-ancestors directive to mitigate clickjacking attacks, which can be used as an entry point for cross-site script inclusion.
  100. Implement Strict Transport Security (HSTS): Enable HSTS to ensure that the application is accessed only over secure, encrypted connections (HTTPS). This prevents malicious actors from intercepting or modifying the requests and responses, reducing the risk of script inclusion.

In conclusion, implementing these best practices is crucial for enhancing the security of your application. However, it is equally important to validate their effectiveness. Regular security tests are recommended to strengthen your application’s security and ensure a robust and safeguarded digital environment. If you require assistance with these tests, IARM can provide additional layers of security to your web application. 

Get the skills and resources you need to secure your software. IARM’s experts provide 100 actionable tips on how to protect your applications from penetration testing. Learn best practices, tools, and techniques from leading security professionals.

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