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Building a Tech Startup: CTO Playbook

Security and Compliance

Building security-first culture with modern practices: zero trust, AI security, supply chain protection, and compliance frameworks.

Security Landscape in 2025

Security in 2025 extends far beyond traditional perimeter defense. Modern threats include AI-powered attacks, supply chain compromises, and sophisticated social engineering. Zero Trust Architecture is now the standard, assuming breach and verifying every access request regardless of network location.

The rise of AI introduces new security challenges: prompt injection attacks, model poisoning, data leakage through LLMs, and adversarial inputs. Meanwhile, regulatory requirements continue expanding with GDPR, SOC2, ISO27001, and emerging AI governance frameworks requiring proactive compliance strategies.

⚠️ Critical Security Threats (2025)

  • AI-powered phishing and deepfake attacks targeting employees and customers
  • Supply chain attacks through compromised dependencies and build tools
  • Prompt injection and jailbreaking of LLM-powered features
  • Credential stuffing with billions of leaked passwords from breaches
  • Ransomware targeting cloud infrastructure and backups
  • API abuse and scraping with automated tools

Security Foundations: The First 90 Days

As a new CTO or starting a company, implement these security fundamentals immediately. These are non-negotiable baseline requirements that prevent 90% of common attacks.

Week 1: Identity and Access

  • SSO with MFA: Implement company-wide (Google Workspace, Okta, Microsoft 365)
  • Password manager: 1Password or Bitwarden for all team passwords
  • Hardware keys: YubiKeys for privileged accounts (admins, production access)
  • Principle of least privilege: Nobody gets admin by default, grant on-demand access
  • Inventory access: Document who has access to what systems

Week 2-4: Application Security

  • HTTPS everywhere: SSL/TLS for all connections, enforce HSTS headers
  • Secrets management: Never commit secrets, use AWS Secrets Manager or Vault
  • Dependency scanning: Snyk, Dependabot, or Trivy in CI/CD pipeline
  • SAST/DAST: Static and dynamic code analysis (SonarQube, Checkmarx)
  • API security: Rate limiting, authentication, input validation on all endpoints
  • Security headers: CSP, X-Frame-Options, X-Content-Type-Options configured

Month 2-3: Infrastructure Security

  • Network segmentation: Private subnets for databases, public for load balancers
  • Encryption at rest: Enable for databases, S3 buckets, and disk volumes
  • Logging and monitoring: CloudTrail, audit logs, security events to SIEM
  • Backup strategy: Automated backups, test recovery quarterly, offline copies
  • Vulnerability scanning: Weekly scans of infrastructure (Qualys, Tenable)
  • Incident response plan: Documented playbooks, on-call rotation, practice drills

Zero Trust Architecture

Zero Trust means "never trust, always verify." Assume that attackers are already inside your network. Every access request is authenticated, authorized, and encrypted regardless of source location.

Core Zero Trust Principles

1. Verify Explicitly: Authenticate and authorize based on all available data points: user identity, device health, location, data sensitivity.

2. Least Privilege Access: Just-in-time and just-enough-access (JIT/JEA). Time-limited access to specific resources, not blanket permissions.

3. Assume Breach: Minimize blast radius with micro-segmentation. Verify end-to-end encryption. Log everything for forensics.

Implementing Zero Trust

Identity Provider: Okta, Auth0, or Azure AD as central identity source

Device Trust: MDM solution (Jamf, Intune) for device posture checks

Network Access: VPN replacement with Cloudflare Access, Zscaler, or Tailscale

Service-to-Service: mTLS between services, service mesh (Istio) for microservices

Policy Engine: Centralized policy evaluation (OPA, AWS IAM, GCP BeyondCorp)

AI Security Considerations

If you're building AI-powered features or using LLMs, you face unique security challenges that traditional security practices don't address. AI security is an emerging field with evolving best practices.

Prompt Injection Prevention

Validate and sanitize all user inputs to LLMs. Use instruction/data separation. Implement content filtering (Azure Content Safety, Perspective API). Monitor for jailbreaking attempts. Consider prompt firewalls like Rebuff or Lakera Guard.

Data Privacy in AI Pipelines

Don't send PII or sensitive data to third-party LLMs without consent. Use data anonymization or synthetic data for training. Implement data retention policies. Consider self-hosted models (Llama 2, Mistral) for sensitive use cases.

Model Security and Governance

Version control for prompts and models. Monitor model outputs for bias, toxicity, and hallucinations. Implement human-in-the-loop for high-stakes decisions. Log all AI interactions for audit trails. Regular security reviews of AI features.

Supply Chain Security

Modern applications depend on thousands of open-source packages. Supply chain attacks compromise these dependencies to distribute malware. Examples: SolarWinds, Log4Shell, event-stream npm package.

Supply Chain Best Practices

  • Software Bill of Materials (SBOM): Generate and track all dependencies (Syft, SPDX)
  • Dependency scanning: Automated CVE checking (Snyk, Dependabot, Renovate)
  • Private registries: Mirror public packages through JFrog or GitHub Packages
  • Signed artifacts: Verify signatures on packages and container images (Sigstore, Notary)
  • Lock files: Pin exact versions, review dependency updates carefully
  • Least privilege builds: Minimize build pipeline permissions, use ephemeral credentials

Container Image Security

Base images: Use official, minimal images (distroless, Alpine). Scan regularly.

Multi-stage builds: Don't include build tools in runtime images

Image scanning: Trivy, Clair, or Snyk in CI pipeline and registry

Runtime security: Falco or Sysdig for runtime threat detection

Registry security: Private registries with access controls, vulnerability scanning

Compliance Frameworks

SOC 2 Type II

When: Required by enterprise customers, plan 6-9 months for first audit

What: Demonstrates security controls for confidentiality, availability, integrity

How: Use compliance automation tools (Vanta, Drata, Secureframe)

Cost: $15-50K for first audit, ongoing $10-20K annually

Key controls: Access management, change management, encryption, monitoring, incident response

GDPR / Data Privacy

Applies to: Any company processing EU citizen data, regardless of location

Key requirements: Consent, data minimization, right to deletion, breach notification (72hrs)

Implementation: Privacy by design, data mapping, DPO or privacy officer

Penalties: Up to 4% of global revenue or €20M, whichever is greater

Tools: OneTrust, TrustArc for privacy management and consent tracking

ISO 27001

When: Required for international customers, government contracts

What: International standard for information security management systems (ISMS)

Timeline: 12-18 months for first certification

Benefits: Demonstrates mature security practices, risk management framework

HIPAA (Healthcare)

Applies to: Protected Health Information (PHI) in US healthcare

Requirements: Encryption, access controls, audit logs, BAAs with vendors

Architecture: Use HIPAA-eligible services (AWS, GCP, Azure BAAs)

Penalties: $100-50K per violation, up to $1.5M per year per violation type

Security Culture and Training

Technology alone doesn't create security. You need a security-aware culture where every team member understands their role in protecting the company and customers.

Building Security Culture

  • Security champions: Designate security advocates in each team, not just security team
  • Regular training: Quarterly security awareness training, phishing simulations
  • Security by default: Make secure option the easy option in tools and processes
  • Blameless postmortems: Learn from incidents without finger-pointing
  • Bug bounty program: HackerOne or Bugcrowd once product-market fit achieved
  • Security budget: Allocate 5-10% of engineering budget to security initiatives

Key Takeaways

  • Security is not optional: implement SSO, MFA, secrets management in first 90 days
  • Zero Trust Architecture: never trust, always verify. Assume breach and minimize blast radius
  • AI introduces new risks: prompt injection, data leakage, model poisoning require new defenses
  • Supply chain security: SBOM, dependency scanning, signed artifacts are now table stakes
  • Compliance early: SOC2 takes 6-9 months, start before enterprise sales need it
  • Security culture: train everyone, security champions in each team, blameless learning