Case Study - Passed Fortune 500 security review and closed $250K enterprise deal

The Problem

PayFlow used Cursor to build a B2B payment reconciliation platform in 2 weeks. The AI-assisted development was incredibly productive—they shipped features fast, iterated based on customer feedback, and landed several mid-market customers.

Then they got their first Fortune 500 inbound lead. The procurement team requested:

• Third-party security assessment
• Penetration testing results
• SOC 2 Type II report (or timeline to obtain)
• Answers to 200+ security questionnaire questions

The founder hired a security consultant to conduct the assessment. The result was devastating: 27 critical vulnerabilities, 48 high-severity findings, and a recommendation not to proceed with the deal until fundamental security issues were addressed.

Critical Findings

The security assessment revealed:

• Authentication: No session management, weak password requirements, no MFA
• API Security: No rate limiting, insufficient input validation, exposed admin endpoints
• Secrets Management: API keys hardcoded in client-side code and committed to git
• Data Security: Payment data stored without encryption, no data retention policy
• Infrastructure: Production and dev in same AWS account, overly permissive IAM roles
• Monitoring: No security logging, no intrusion detection, no incident response plan
• Compliance: No data processing agreements, unclear data handling practices

The enterprise prospect gave them 90 days to address the issues or the deal was off.

Our Solution

We had a tight timeline: 4 weeks to fix critical issues, prepare documentation, and pass re-assessment.

Week 1: Triage & Prioritization We categorized all findings by business impact and implementation complexity. Focus: fix deal-blockers first, then build sustainable security foundation.

Priority 1: Authentication & Access Control

• Implemented Auth0 with MFA and SSO support
• Added proper session management with secure tokens
• Implemented RBAC with least-privilege access
• Created admin audit logs for all privileged operations

Priority 2: API Security

• Added Cloudflare rate limiting and DDoS protection
• Implemented comprehensive input validation
• Removed exposed admin endpoints, added proper authentication
• Created API key rotation mechanism

Priority 3: Data Protection

• Migrated all payment data to encrypted database (AES-256)
• Implemented encryption-in-transit (TLS 1.3) with certificate pinning
• Created data retention policy and automated cleanup
• Documented data flows and PII handling

Week 2-3: Infrastructure Hardening

• Separated AWS accounts (dev, staging, prod)
• Implemented least-privilege IAM with temporary credentials
• Added AWS GuardDuty for threat detection
• Configured VPCs with private subnets for databases
• Removed all hardcoded secrets, migrated to AWS Secrets Manager
• Implemented Infrastructure as Code with Terraform

Week 4: Monitoring & Documentation

• Integrated Sentry for error tracking
• Configured CloudWatch alarms for security events
• Implemented comprehensive audit logging (who, what, when, where)
• Created incident response runbooks
• Prepared security documentation for re-assessment
• Conducted team security training

What we did

The Outcome

PayFlow passed the Fortune 500 security re-assessment and closed the deal within 30 days of completing the hardening sprint.

Immediate Business Impact:

• $250K annual contract signed (previously blocked)
• Three additional enterprise prospects moved forward (previously stalled)
• Security became a sales advantage instead of a blocker
• Founder now confidently discusses security in enterprise sales calls

Technical Transformation:

• Zero critical vulnerabilities in production
• 99.9% uptime with proper monitoring and alerting
• Mean time to patch CVEs: < 7 days (was: didn't know about CVEs)
• Infrastructure that scales to thousands of customers

Team Evolution: The engineering team (2 developers) learned security best practices through the engagement:

• Security code review process in place
• Automated security scanning in CI/CD
• Clear separation of environments
• Documented security policies and procedures

Long-term Foundation: PayFlow now has the security foundation to pursue:

• SOC 2 Type II certification (in progress)
• PCI compliance (for credit card processing)
• Enterprise contracts with banks and financial institutions

Lessons Learned

For Founders Using AI Development Tools

1. AI tools are incredible for speed, not security: Cursor helped PayFlow ship fast, but didn't implement enterprise-grade security architecture
2. Security gaps block enterprise deals: $250K deal was 30 days away—if they'd built security correctly from the start
3. Retrofitting is expensive: Cost 4 weeks + $12K to fix what could have been built correctly for less
4. Security becomes a competitive advantage: Enterprise buyers now see PayFlow as more secure than competitors

Technical Insights

1. Authentication is critical: Most enterprise security reviews focus heavily on who can access what
2. Secrets in code = instant fail: One hardcoded API key can block entire deals
3. Monitoring proves you're serious: Enterprise buyers want to see you can detect and respond to incidents
4. Documentation matters: Technical controls are only half the story—you need to document everything

Where They Are Now

PayFlow continues with SafeStack's Growth tier Guardrails subscription ($3K/month):

• Monthly security scans and patching
• Quarterly penetration testing
• SOC 2 audit support (certification expected Q1 2025)
• Ongoing security advisory for new features

Revenue Impact:

• 6 enterprise customers (was: 0)
• $800K ARR from enterprise segment
• 40% of inbound leads specifically mention security as differentiator

The founder's advice to other AI-dev builders: "Build security in from day one, or budget to retrofit it before your first enterprise deal. We got lucky with a 90-day window. Most prospects won't wait."