SaaS CRM Security Hardening

Project Overview

I run a multi‑tenant SaaS CRM that is already live on a private VPS.

Frontend: Next.js (React 18)

Backend: Node.js (Express / Nest‑style architecture)

Database: MongoDB Atlas (one cluster per tenant)

Hosting: Ubuntu 22.04 VPS on Hostinger, Docker‑based deployment

I now need to harden the platform so that no developer —including those with full source‑code access—or anyone with server credentials can view tenant data in plaintext, while still retaining the ability to:

ship new features and bug‑fixes;

investigate production issues (logs, metrics, traces);

perform schema migrations and backups.

Core Security Objectives
Zero‑knowledge architecture: Running code may manipulate data, but humans (developers, contractors, admins) must not be able to read it.

Client isolation: Each tenant keeps its own MongoDB project/cluster; cross‑tenant leakage must be provably impossible.

Auditable operations: Every privileged action (deploy, shell access, DB command) should leave an immutable audit trail.

Rapid incident response: Security controls must not block hot‑fixes or on‑call diagnostics.

Scope of Work
Threat‑model & gap analysis of the existing stack.

Design & implementation of one or more of the following (justify your mix):

Client‑side / driver‑side Field Level Encryption or Queryable Encryption.

Secret‑management pipeline (GitHub Actions, HashiCorp Vault, AWS Secrets Manager, etc.) that keeps connection strings and KMS keys out of source control and build logs.

Hardened runtime: non‑root containers, read‑only filesystems, egress‑restricted network policies.

CI/CD attestation and image signing (Cosign, SLSA provenance) so only vetted images reach production.

Confidential computing (AMD SEV / Intel TDX) or enclave‑based key access (AWS Nitro Enclaves) for high‑assurance tenants.

Centralized log & metrics stack with payload redaction.

Written run‑book for emergency debugging without data exposure.

Knowledge transfer session + documentation so future devs can follow the process.

Deliverables
Architectural diagram of the proposed solution.

Infrastructure‑as‑Code (Terraform / Pulumi / Ansible) and CI/CD scripts.

Updated application code samples or middleware demonstrating encryption and key retrieval.

Security test plan and pass/fail report (unit + integration).

Final report summarizing residual risks and future hardening options.

What to include in your proposal
Approach: Which controls you’d combine and why.

Experience: Refs to similar zero‑knowledge or regulated‑industry projects (HIPAA, GDPR, PCI‑DSS).

Timeline & milestones with rough effort estimate (hrs or days).

Tooling stack you prefer for secrets, image signing, monitoring, etc.

Post‑deployment support options (SLA, hourly rate).

Nice‑to‑have skills
Kubernetes hardening & network policies

Operating MongoDB under client‑side encryption at scale

Familiarity with SOC 2 Type II or ISO 27001 controls

Incident‑response playbook authoring

How to stand out
Provide a brief threat‑model sketch in your cover letter.

Share a public GitHub repo or gist showing encryption‑at‑rest or CI/CD attestation code.

Suggest at least one measurement for “developer cannot read data” that we can verify in a demo.

Looking forward to your secure‑by‑design strategies!