Enterprise AI Security Model
Version 1.0 | Last Updated: December 2024
Abstract
This document outlines a comprehensive security model for enterprise AI deployments, covering threat surface analysis, mitigation strategies, and compliance framework mapping. The model addresses unique AI-specific vulnerabilities including prompt injection, model poisoning, data exfiltration, and adversarial attacks, while providing practical implementation guidance for HIPAA, SOC 2, GDPR, and ISO 27001 compliance.
Threat Surface Analysis
1. Model Poisoning Attacks
Description: Adversaries inject malicious data into training datasets to corrupt model behavior.
Attack Vectors:
- Data poisoning during initial training (backdoor attacks)
- Continuous learning exploitation in production systems
- Supply chain attacks on pre-trained models
Impact: Model produces incorrect outputs for specific inputs, enabling targeted manipulation.
Mitigation:
- Validate and sanitize all training data sources
- Implement data provenance tracking
- Use differential privacy during training
- Freeze models after validation in high-risk scenarios
2. Data Exfiltration Risks
Description: Sensitive data leaks through model outputs, embeddings, or model weights.
Attack Vectors:
- Model inversion attacks (reconstructing training data from model)
- Membership inference (determining if data was in training set)
- Embedding extraction (stealing vector representations)
- Prompt injection to extract sensitive information
Impact: Exposure of PII, PHI, trade secrets, or proprietary algorithms.
Mitigation:
- Implement output filtering and data loss prevention (DLP)
- Use differential privacy techniques
- Encrypt embeddings at rest and in transit
- Apply k-anonymity to training data
- Regular security audits of model outputs
3. Prompt Injection Vulnerabilities
Description: Malicious users craft inputs that manipulate LLM behavior to bypass security controls.
Attack Vectors:
- Direct injection: "Ignore previous instructions and..."
- Indirect injection: Malicious content in retrieved documents
- Jailbreaking: Bypassing safety guardrails
- Context manipulation in multi-turn conversations
Impact: Unauthorized data access, policy violations, reputation damage.
Mitigation:
- Input validation and sanitization
- Prompt firewalls (detect adversarial patterns)
- Separate system prompts from user inputs
- Rate limiting and anomaly detection
- Human-in-the-loop for sensitive operations
4. Model Inversion Attacks
Description: Adversaries reconstruct training data or model architecture through repeated queries.
Attack Vectors:
- Black-box attacks (query model repeatedly to infer behavior)
- White-box attacks (exploit access to model weights)
- Side-channel attacks (timing, memory usage patterns)
Impact: Theft of proprietary models, exposure of training data.
Mitigation:
- Rate limiting and query budgets
- Model watermarking to detect theft
- Noise injection in outputs
- Restrict API access (authentication required)
Security Architecture: Defense in Depth
Architecture Diagram: Layered Security Model
┌─────────────────────────────────────────────────────────┐
│ Layer 1: Perimeter │
│ - Firewall, WAF, DDoS protection │
│ - API Gateway with authentication (OAuth 2.0, SAML) │
└─────────────────┬───────────────────────────────────────┘
│
┌─────────────────▼───────────────────────────────────────┐
│ Layer 2: Application Security │
│ - Input validation & sanitization │
│ - Prompt firewall (adversarial pattern detection) │
│ - Output filtering & DLP │
│ - Rate limiting (per user, per IP) │
└─────────────────┬───────────────────────────────────────┘
│
┌─────────────────▼───────────────────────────────────────┐
│ Layer 3: Data Security │
│ - Encryption at rest (AES-256) │
│ - Encryption in transit (TLS 1.3) │
│ - Role-based access control (RBAC) │
│ - Document-level permissions │
│ - Audit logging (tamper-proof) │
└─────────────────┬───────────────────────────────────────┘
│
┌─────────────────▼───────────────────────────────────────┐
│ Layer 4: Infrastructure Security │
│ - Network isolation (VPCs, VLANs) │
│ - Secrets management (HashiCorp Vault, AWS KMS) │
│ - OS hardening & patching │
│ - Intrusion detection (IDS/IPS) │
└─────────────────────────────────────────────────────────┘
Figure 1: Four-layer defense-in-depth security architecture for enterprise AI systems. Each layer provides independent security controls, ensuring that compromise of one layer does not result in total system failure.
Layer 1: Infrastructure Security
- Network Isolation: Deploy AI systems in isolated VPCs/VNets with strict firewall rules
- Encryption at Rest: AES-256 for all storage (databases, vector stores, model weights)
- Encryption in Transit: TLS 1.3 for all API communications
- Key Management: HSM-backed key rotation (AWS KMS, Azure Key Vault, HashiCorp Vault)
- Secrets Management: Never hardcode credentials; use secret managers
Layer 2: Application Security
- Input Validation: Sanitize user inputs, check for injection patterns
- Output Sanitization: Filter responses for PII/PHI before returning to users
- Rate Limiting: Prevent abuse (e.g., 100 requests/hour/user)
- Session Management: Short-lived tokens, enforce re-authentication
- Prompt Firewall: Detect and block adversarial prompts in real-time
Layer 3: Data Security
- Access Controls (RBAC): Users only access data they're authorized for
- Data Classification: Tag data as Public, Internal, Confidential, Restricted
- Audit Logging: Log all queries, retrievals, and model interactions
- Data Minimization: Only collect and process necessary data
- Anonymization: Apply k-anonymity or differential privacy to sensitive datasets
Compliance Framework Mapping
HIPAA Compliance
| HIPAA Requirement | Security Control | Implementation |
|---|---|---|
| §164.312(a)(1) Access Control | RBAC with MFA | SAML SSO + Time-based access reviews |
| §164.312(a)(2)(iv) Encryption | AES-256 at rest, TLS 1.3 in transit | Full disk encryption + Encrypted vector DB |
| §164.312(b) Audit Controls | Comprehensive logging | Tamper-proof logs with 7-year retention |
| §164.308(a)(1)(ii)(D) Information System Activity Review | Security monitoring | SIEM with anomaly detection |
SOC 2 Trust Services Criteria
| Trust Principle | Security Control |
|---|---|
| Security (CC6.1) | Logical access controls, encryption, firewall rules |
| Availability (A1.1) | High availability architecture, disaster recovery plan |
| Processing Integrity (PI1.1) | Input validation, output verification, audit trails |
| Confidentiality (C1.1) | Encryption, access controls, DLP |
| Privacy (P1.1) | Data minimization, anonymization, user consent |
GDPR Data Protection Controls
- Article 5 (Data Minimization): Only collect necessary data for AI functionality
- Article 17 (Right to Erasure): Ability to delete user data from training sets and vector DB
- Article 25 (Data Protection by Design): Privacy controls built into architecture
- Article 32 (Security of Processing): Encryption, pseudonymization, access controls
- Article 35 (DPIA): Data Protection Impact Assessment for high-risk AI systems
Implementation Checklist
Phase 1: Infrastructure (Week 1-2)
- ☐ Deploy AI systems in isolated VPC/VNet
- ☐ Configure firewall rules (deny-by-default)
- ☐ Enable encryption at rest for all storage
- ☐ Set up TLS 1.3 for API endpoints
- ☐ Implement secrets management (Vault/KMS)
Phase 2: Application Security (Week 3-4)
- ☐ Implement input validation and sanitization
- ☐ Deploy prompt firewall for adversarial detection
- ☐ Configure rate limiting (per user, per IP)
- ☐ Add output filtering / DLP
- ☐ Enable audit logging for all AI interactions
Phase 3: Data Security (Week 5-6)
- ☐ Implement RBAC with SSO integration
- ☐ Configure document-level access controls
- ☐ Set up data classification tags
- ☐ Deploy SIEM for security monitoring
- ☐ Conduct security penetration testing
Related Documentation
- Zero-Trust RAG Design - Secure retrieval architecture
- Enterprise AI Governance Principles
- Private AI - Deployment model