The Startup Founder’s Security Guide part 3 - Tech

Introduction

In our previous section, we discussed the human element of security, covering training, awareness, and best practices for securing your team. Now, let's shift our focus to technology—specifically, your code and infrastructure .

Every company’s tech stack is unique, but there are common security principles and best practices that all startups should follow. Security isn’t something you bolt on later; it should be embedded in your development and operational processes from day one.

In fast-growing startups, speed is often prioritized over security. Many teams see security as a blocker—something that slows down feature releases, requires additional testing, or introduces complexity. While this concern is valid, it often stems from poorly designed development workflows. The reality is that security should be part of your pipeline, not an afterthought. When integrated properly, it enhances stability, protects users, and ensures business continuity.

With that in mind, let's dive into the two major components of security in your tech stack: Code and Infrastructure

Code Security

Your source code is the foundation of your business. It drives your products and services, handles sensitive customer data, and, in many cases, serves as a competitive advantage. Securing your codebase should be a top priority to prevent data leaks, breaches, and availability issues.

1. Secure Code Development Practices

Most developers are not security experts, and in fast-paced environments, security often takes a backseat. To mitigate risks, automated security tools should be embedded in the development lifecycle:

• Static Application Security Testing (SAST): Tools like Semgrep and GitHub CodeQL can scan your codebase for vulnerabilities, including SQL injection, remote code execution (RCE), and cross-site scripting (XSS). While some tools require paid licenses, open-source alternatives exist.
• Code Review and Approval Process: Developers should never review and approve their own pull requests (PRs). Implementing a structured review process with at least one additional reviewer helps prevent security blind spots.
• Periodic Security Reviews: While automated tools catch many issues, complex business logic flaws require manual security reviews and penetration testing.
  

2. Secrets Management

Hardcoding credentials in source code is one of the most common and dangerous mistakes. Exposed secrets can lead to full system compromises. Follow these best practices:

• Use Secure Storage: Environment variables, HashiCorp Vault, AWS Secrets Manager, or GitHub Actions secrets should be used to manage credentials.
• Limit Privileges: No single developer should have unrestricted access to both code and production systems. Apply the principle of least privilege to mitigate insider threats and compromised accounts.
• Prevent Leaks: Tools like GitLeaks can scan repositories for API keys, database credentials, and other sensitive information.
  

3. Adopt an "Assumed Breach" Mindset

In the age of AI-driven attacks and rapid feature cloning, assume that your source code will be compromised at some point. Your real competitive advantage lies in data security, key management, and operational resilience. Implement measures like:

• Rate limiting and anomaly detection to prevent abuse.
• API key rotation policies to limit damage in case of leaks.
• Zero Trust Architecture, ensuring access is continuously verified rather than implicitly granted.
  

4. Securing High-Sensitive Endpoints

Certain endpoints, such as login, payment processing, and authentication-related APIs, require additional layers of security to prevent abuse and exploitation. Follow these best practices:

• Implement CAPTCHA on login and payment pages to mitigate automated brute-force attacks.
• Enforce Rate Limiting to prevent credential stuffing and denial-of-service attacks.
• Validate Inputs on the Backend: Never rely solely on frontend validation; all input validation should be enforced on the server side to prevent tampering.
• Avoid Using Sequential IDs: Use UUIDs instead of numerical IDs to reduce the risk of Insecure Direct Object References (IDOR) attacks.
• Design a Secure Authentication System: Avoid rolling your own authentication; leverage well-tested solutions such as OAuth2, OpenID Connect, or JSON Web Tokens (JWT) with proper expiration and refresh mechanisms.

By implementing these practices, you can significantly reduce the attack surface and improve the security of your critical endpoints.

Infrastructure Security

Your infrastructure is the backbone of your company. It enables data storage, runs your code, and ensures high availability. However, it also introduces security risks that must be addressed. While every environment is different, there are common security principles to follow.

1. Cloud Security Best Practices

With the rise of cloud computing, many small and medium-sized companies are leveraging platforms like AWS, GCP, and Azure for fast deployment and scalability. While these services offer flexibility, they require careful security configurations:

• Follow the Principle of Least Privilege: Always grant the minimum necessary permissions. For example, if a service needs to upload files to an S3 bucket, its credentials should allow only uploads, not deletions or downloads.
• Enable Logging and Monitoring: Continuously monitor logs for anomalies, unauthorized access, leaked credentials, or excessive resource usage. Tools like AWS CloudTrail, Azure Monitor, and Google Cloud Logging can help.
• Enforce Network Segmentation: Design services with network separation in mind. Use VPCs, subnets, and firewall rules to limit lateral movement within your infrastructure.
• Secure Uncommon Services: If using niche or less-common cloud services, follow their official security guidelines to prevent accidental exposure of sensitive data.
  

2. Harden Your Infrastructure

• Reduce Unused Services and Users: Regularly audit your infrastructure and remove unused services, users, and permissions to reduce your attack surface.
• Secure Containers and Virtual Machines:
  • Use minimalist base images (e.g., Alpine Linux) to reduce vulnerabilities.
  • Implement container scanning tools like Trivy or Clair to detect vulnerabilities.
  • Run containers as non-root users to limit damage in case of compromise.
• Patch and Update Regularly: Ensure all infrastructure components, including cloud instances, containers, and databases, receive security updates regularly.
• Restrict Public Exposure: Avoid exposing management interfaces like SSH, RDP, or Kubernetes dashboards directly to the internet. Use VPNs, bastion hosts, or Zero Trust solutions instead.

3. Database and Network Security

• Keep Databases in Private Subnets: Databases should never be directly accessible from the internet. Use bastion hosts or VPNs for secure access.
• Enable Firewalls and Security Groups: Firewalls should be enabled at both the network and application levels to block unauthorized traffic.
• Monitor and Audit DNS Records: Regularly review DNS records to detect unauthorized changes that could indicate domain hijacking.
  

Conclusion

Security is a continuous process, not a one-time setup. In this post, we provided an overview of securing your code, infrastructure, and third-party SaaS. Our goal was to open your eyes to common security risks and best practices.

However, this is just the beginning. In our next posts, we will dive deeper into each aspect, covering hands-on strategies for building a security pipeline, automating security checks, and enforcing best practices at scale.

By embedding security into your development and infrastructure workflows, you can move fast without breaking things—or exposing your startup to cyber threats.