Comprehensive security guidelines, threat model, and mitigation strategies for the SciFind backend.

• Security Overview
• Threat Model
• Authentication & Authorization
• API Security
• Data Protection
• Infrastructure Security
• Provider Security
• Monitoring & Incident Response
• Security Best Practices
• Compliance & Auditing
• Security Checklist

SciFind backend implements a defense-in-depth security strategy with multiple layers of protection:

1. Perimeter Security: API gateway with rate limiting and input validation
2. Application Security: Secure coding practices and dependency management
3. Data Security: Encryption at rest and in transit
4. Infrastructure Security: Container security and network isolation
5. Operational Security: Monitoring, logging, and incident response

graph TB
    subgraph "External Threats"
        ATTACKER[Malicious Actors]
        BOTS[Automated Bots]
        INSIDER[Insider Threats]
    end

    subgraph "Perimeter Defense"
        WAF[Web Application Firewall]
        RATE_LIMIT[Rate Limiting]
        DDoS_PROTECTION[DDoS Protection]
    end

    subgraph "Application Layer"
        AUTH[Authentication]
        AUTHZ[Authorization]
        INPUT_VAL[Input Validation]
        OUTPUT_ENC[Output Encoding]
    end

    subgraph "Data Layer"
        ENCRYPT_TRANSIT[TLS Encryption]
        ENCRYPT_REST[Database Encryption]
        ACCESS_CONTROL[Access Controls]
    end

    subgraph "Infrastructure"
        CONTAINER_SEC[Container Security]
        NETWORK_SEG[Network Segmentation]
        SECRETS_MGMT[Secrets Management]
    end

    subgraph "Monitoring"
        LOGGING[Security Logging]
        SIEM[SIEM Integration]
        ALERTS[Real-time Alerts]
    end

    ATTACKER --> WAF
    BOTS --> RATE_LIMIT
    INSIDER --> AUTH
    
    WAF --> AUTH
    RATE_LIMIT --> INPUT_VAL
    DDoS_PROTECTION --> AUTHZ
    
    AUTH --> ENCRYPT_TRANSIT
    INPUT_VAL --> ACCESS_CONTROL
    OUTPUT_ENC --> ENCRYPT_REST
    
    ENCRYPT_TRANSIT --> CONTAINER_SEC
    ACCESS_CONTROL --> NETWORK_SEG
    ENCRYPT_REST --> SECRETS_MGMT
    
    CONTAINER_SEC --> LOGGING
    NETWORK_SEG --> SIEM
    SECRETS_MGMT --> ALERTS

    style ATTACKER fill:#ff6b6b
    style BOTS fill:#ff6b6b
    style INSIDER fill:#ff6b6b
    style WAF fill:#4ecdc4
    style AUTH fill:#45b7d1
    style ENCRYPT_TRANSIT fill:#96ceb4
    style CONTAINER_SEC fill:#feca57
    style LOGGING fill:#ff9ff3

• SQL Injection: Malicious SQL queries through input fields
• Cross-Site Scripting (XSS): Injection of malicious scripts
• Cross-Site Request Forgery (CSRF): Unauthorized actions on behalf of users
• Input Validation Bypass: Malformed data to bypass security controls

Mitigations:

• Parameterized queries with GORM ORM
• Input validation and sanitization
• Output encoding
• CSRF tokens for state-changing operations

• Broken Authentication: Weak or compromised authentication mechanisms
• Broken Authorization: Inadequate access controls
• Sensitive Data Exposure: Leaking of confidential information
• Rate Limit Bypass: Overwhelming the system with requests

Mitigations:

• Strong API key authentication
• Role-based access control (RBAC)
• Data encryption and masking
• Multi-layer rate limiting

• Container Escape: Breaking out of container isolation
• Privilege Escalation: Gaining unauthorized elevated access
• Network Attacks: Man-in-the-middle, eavesdropping
• Supply Chain Attacks: Compromised dependencies

Mitigations:

• Distroless container images
• Non-root user execution
• TLS encryption for all communications
• Dependency scanning and vulnerability management

• Database Compromise: Unauthorized access to stored data
• Backup Exposure: Insecure backup storage
• Log Data Leakage: Sensitive information in logs
• Memory Dumps: Extraction of data from memory

Mitigations:

• Database encryption at rest
• Secure backup procedures
• Log sanitization
• Memory protection techniques

SciFind uses API key-based authentication for simplicity and performance:

security:
  api_keys:
    - "prod-key-1-$(openssl rand -hex 32)"
    - "prod-key-2-$(openssl rand -hex 32)"
  rate_limit:
    enabled: true
    requests: 1000
    window: "1m"
    burst_size: 50

• Key Generation: Use cryptographically secure random generation
• Key Rotation: Rotate keys regularly (recommended: every 90 days)
• Key Storage: Store keys in secure secret management systems
• Key Transmission: Only transmit over HTTPS

# Generate secure API key
API_KEY=$(openssl rand -hex 32)

# Set in environment
export SCIFIND_SECURITY_API_KEYS="$API_KEY"

# Use in requests
curl -H "Authorization: Bearer $API_KEY" https://api.scifind.com/v1/search

Currently implements simple API key-based authorization. Future enhancements planned:

# Future implementation
roles:
  reader:
    permissions: ["search:read", "papers:read"]
  admin:
    permissions: ["*"]
  researcher:
    permissions: ["search:*", "papers:read", "analytics:read"]

All API inputs are validated using Go's validator package:

type SearchRequest struct {
    Query    string `json:"query" validate:"required,min=1,max=500"`
    Limit    int    `json:"limit" validate:"min=1,max=100"`
    Offset   int    `json:"offset" validate:"min=0"`
    Provider string `json:"provider" validate:"oneof=arxiv semantic_scholar exa tavily"`
}

Multi-layered rate limiting protects against abuse:

security:
  rate_limit:
    enabled: true
    requests: 1000        # requests per window
    window: "1m"          # time window
    burst_size: 50        # burst allowance

// Search endpoint: 100 req/min
// Health endpoint: No limit
// Admin endpoints: 10 req/min

// Rate limiting middleware
func RateLimitMiddleware(cfg RateLimitConfig) gin.HandlerFunc {
    limiter := rate.NewLimiter(rate.Every(time.Minute), cfg.BurstSize)
    return gin.HandlerFunc(func(c *gin.Context) {
        if !limiter.Allow() {
            c.JSON(429, gin.H{"error": "Rate limit exceeded"})
            c.Abort()
            return
        }
        c.Next()
    })
}

// Security middleware adds protective headers
func SecurityHeaders() gin.HandlerFunc {
    return func(c *gin.Context) {
        c.Header("X-Content-Type-Options", "nosniff")
        c.Header("X-Frame-Options", "DENY")
        c.Header("X-XSS-Protection", "1; mode=block")
        c.Header("Strict-Transport-Security", "max-age=31536000; includeSubDomains")
        c.Header("Content-Security-Policy", "default-src 'self'")
        c.Next()
    }
}

security:
  cors:
    enabled: true
    allowed_origins: ["https://scifind.com", "https://app.scifind.com"]
    allowed_methods: ["GET", "POST", "PUT", "DELETE", "OPTIONS"]
    allowed_headers: ["Authorization", "Content-Type", "X-Request-ID"]
    max_age: "12h"
    credentials: false

All communications use TLS 1.3:

server:
  tls:
    enabled: true
    cert_file: "/etc/ssl/certs/scifind.crt"
    key_file: "/etc/ssl/private/scifind.key"
    min_version: "1.3"
    cipher_suites:
      - "TLS_AES_128_GCM_SHA256"
      - "TLS_AES_256_GCM_SHA384"
      - "TLS_CHACHA20_POLY1305_SHA256"

# Generate certificate with Let's Encrypt
certbot certonly --standalone -d api.scifind.com

# Auto-renewal
0 0,12 * * * certbot renew --quiet

Database encryption protects stored data:

-- Enable transparent data encryption
ALTER SYSTEM SET ssl = on;
ALTER SYSTEM SET ssl_cert_file = 'server.crt';
ALTER SYSTEM SET ssl_key_file = 'server.key';

-- Column-level encryption for sensitive data
CREATE EXTENSION IF NOT EXISTS pgcrypto;

-- Encrypt sensitive fields
INSERT INTO papers (title, encrypted_content) 
VALUES ('Paper Title', pgp_sym_encrypt('sensitive content', 'encryption_key'));

# Encrypted database backup
pg_dump scifind | gpg --cipher-algo AES256 --compress-algo 1 --symmetric --output backup.sql.gpg

# Encrypted backup verification
gpg --decrypt backup.sql.gpg | head -10

• Collect only necessary data
• Anonymize personal information
• Regular data purging

// Sanitize sensitive data from logs
func sanitizeLogData(data map[string]interface{}) map[string]interface{} {
    sensitiveFields := []string{"api_key", "password", "token", "secret"}
    
    for _, field := range sensitiveFields {
        if _, exists := data[field]; exists {
            data[field] = "[REDACTED]"
        }
    }
    
    return data
}

# Use distroless base image
FROM gcr.io/distroless/static:nonroot

# Run as non-root user
USER nonroot:nonroot

# Copy only necessary files
COPY --from=builder /app/scifind-backend /app/scifind-backend

# Set read-only filesystem
RUN chmod 755 /app/scifind-backend

ENTRYPOINT ["/app/scifind-backend"]

# Kubernetes security context
apiVersion: apps/v1
kind: Deployment
spec:
  template:
    spec:
      securityContext:
        runAsNonRoot: true
        runAsUser: 65534
        fsGroup: 65534
      containers:
      - name: scifind-backend
        securityContext:
          allowPrivilegeEscalation: false
          readOnlyRootFilesystem: true
          capabilities:
            drop:
            - ALL
          runAsNonRoot: true
          runAsUser: 65534

# Scan container for vulnerabilities
trivy image scifind-backend:latest

# Continuous scanning in CI/CD
grype scifind-backend:latest --fail-on medium

# Kubernetes network policy
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: scifind-network-policy
spec:
  podSelector:
    matchLabels:
      app: scifind-backend
  policyTypes:
  - Ingress
  - Egress
  ingress:
  - from:
    - podSelector:
        matchLabels:
          app: nginx-ingress
    ports:
    - protocol: TCP
      port: 8080
  egress:
  - to:
    - podSelector:
        matchLabels:
          app: postgres
    ports:
    - protocol: TCP
      port: 5432

# Istio security policy
apiVersion: security.istio.io/v1beta1
kind: PeerAuthentication
metadata:
  name: scifind-mtls
spec:
  selector:
    matchLabels:
      app: scifind-backend
  mtls:
    mode: STRICT

apiVersion: v1
kind: Secret
metadata:
  name: scifind-secrets
type: Opaque
stringData:
  api-key: "secure-api-key-here"
  db-password: "secure-db-password"
  semantic-scholar-key: "ss-api-key"

# AWS Secrets Manager
aws secretsmanager create-secret \
  --name scifind/api-keys \
  --description "SciFind API keys" \
  --secret-string '{"semantic_scholar":"key","exa":"key"}'

# HashiCorp Vault
vault kv put secret/scifind \
  semantic_scholar_key="your-key" \
  exa_key="your-key"

Each external provider requires secure API key handling:

type ProviderConfig struct {
    APIKey      string `json:"api_key,omitempty" yaml:"api_key,omitempty"`
    APISecret   string `json:"api_secret,omitempty" yaml:"api_secret,omitempty"`
    Timeout     time.Duration
    MaxRetries  int
    RateLimit   RateLimitConfig
}

# Store provider keys in environment variables
export SCIFIND_PROVIDERS_SEMANTIC_SCHOLAR_API_KEY="your-secure-key"
export SCIFIND_PROVIDERS_EXA_API_KEY="your-secure-key"
export SCIFIND_PROVIDERS_TAVILY_API_KEY="your-secure-key"

func signRequest(req *http.Request, secret string) error {
    body, _ := io.ReadAll(req.Body)
    timestamp := strconv.FormatInt(time.Now().Unix(), 10)
    
    message := fmt.Sprintf("%s%s%s", timestamp, req.Method, string(body))
    mac := hmac.New(sha256.New, []byte(secret))
    mac.Write([]byte(message))
    signature := hex.EncodeToString(mac.Sum(nil))
    
    req.Header.Set("X-Timestamp", timestamp)
    req.Header.Set("X-Signature", signature)
    
    return nil
}

// Prevent cascade failures
circuit := &CircuitBreakerConfig{
    FailureThreshold: 5,
    Timeout:         60 * time.Second,
    MaxRequests:     10,
}

// Log security events
type SecurityEvent struct {
    Type        string    `json:"type"`
    Severity    string    `json:"severity"`
    Source      string    `json:"source"`
    Timestamp   time.Time `json:"timestamp"`
    Details     map[string]interface{} `json:"details"`
    RequestID   string    `json:"request_id"`
}

// Examples of monitored events
const (
    EventTypeAuthFailure      = "auth_failure"
    EventTypeRateLimitHit     = "rate_limit_hit"
    EventTypeSuspiciousQuery  = "suspicious_query"
    EventTypeUnauthorizedAccess = "unauthorized_access"
)

# Prometheus alerting rules
groups:
- name: security_alerts
  rules:
  - alert: HighAuthFailureRate
    expr: rate(auth_failures_total[5m]) > 10
    for: 1m
    annotations:
      summary: "High authentication failure rate detected"
      
  - alert: RateLimitExceeded
    expr: rate_limit_exceeded_total > 100
    for: 30s
    annotations:
      summary: "Rate limit exceeded threshold"
      
  - alert: SuspiciousQuery
    expr: suspicious_query_total > 5
    for: 1m
    annotations:
      summary: "Suspicious search queries detected"

1. Detection: Automated monitoring alerts
2. Assessment: Evaluate threat severity and impact
3. Containment: Isolate affected systems
4. Eradication: Remove threat and vulnerabilities
5. Recovery: Restore normal operations
6. Lessons Learned: Post-incident review

incident_response:
  primary_oncall: "security@scifind.com"
  escalation_path:
    - "lead-engineer@scifind.com"
    - "cto@scifind.com"
  external_contacts:
    - "security-vendor@company.com"

1. Identify source IP/API key
2. Implement temporary rate limit reduction
3. Investigate query patterns
4. Block malicious sources
5. Monitor for continued abuse

1. Immediately isolate affected systems
2. Preserve evidence and logs
3. Assess data exposure scope
4. Notify stakeholders and authorities
5. Implement containment measures

1. Input Validation

   // Always validate and sanitize inputs
   func validateSearchQuery(query string) error {
       if len(query) == 0 {
           return errors.New("query cannot be empty")
       }
       if len(query) > 500 {
           return errors.New("query too long")
       }
       // Check for injection patterns
       if containsSQLInjection(query) {
           return errors.New("invalid characters in query")
       }
       return nil
   }

2. Error Handling

   // Don't expose internal details
   func handleError(err error, c *gin.Context) {
       logger.Error("Internal error", "error", err)
       c.JSON(500, gin.H{
           "error": "Internal server error",
           "request_id": c.GetString("request_id"),
       })
   }

3. Dependency Management

   # Regular dependency updates
   go mod tidy
   go list -json -m all | nancy sleuth
   
   # Vulnerability scanning
   govulncheck ./...

# Production security settings
security:
  api_keys: ["${SECURE_API_KEY_1}", "${SECURE_API_KEY_2}"]
  rate_limit:
    enabled: true
    requests: 1000
    window: "1m"
    burst_size: 50
  cors:
    enabled: true
    allowed_origins: ["https://scifind.com"]
    allowed_methods: ["GET", "POST"]
    credentials: false
  headers:
    x_frame_options: "DENY"
    x_content_type_options: "nosniff"
    x_xss_protection: "1; mode=block"
    strict_transport_security: "max-age=31536000; includeSubDomains"

Daily:

• Monitor security alerts
• Review authentication logs
• Check system resource usage

Weekly:

• Review access logs for anomalies
• Update security documentation
• Test backup and recovery procedures

Monthly:

• Rotate API keys
• Update dependencies
• Conduct security scans
• Review and update firewall rules

Quarterly:

• Security architecture review
• Penetration testing
• Incident response drill
• Security training updates

// Audit log structure
type AuditLog struct {
    Timestamp   time.Time `json:"timestamp"`
    RequestID   string    `json:"request_id"`
    UserID      string    `json:"user_id,omitempty"`
    Action      string    `json:"action"`
    Resource    string    `json:"resource"`
    Success     bool      `json:"success"`
    IP          string    `json:"ip_address"`
    UserAgent   string    `json:"user_agent"`
    Details     map[string]interface{} `json:"details,omitempty"`
}

// Log all API access
func auditMiddleware() gin.HandlerFunc {
    return func(c *gin.Context) {
        start := time.Now()
        c.Next()
        
        audit := AuditLog{
            Timestamp: start,
            RequestID: c.GetString("request_id"),
            Action:    c.Request.Method,
            Resource:  c.Request.URL.Path,
            Success:   c.Writer.Status() < 400,
            IP:        c.ClientIP(),
            UserAgent: c.Request.UserAgent(),
        }
        
        auditLogger.Info("API access", "audit", audit)
    }
}

• Data minimization principles
• Right to deletion implementation
• Privacy by design
• Data protection impact assessments

• Access controls
• System monitoring
• Change management
• Incident response procedures

Application Security:

• Input validation implemented for all endpoints
• SQL injection protection verified
• XSS protection implemented
• CSRF protection for state-changing operations
• Error handling doesn't expose sensitive information
• Dependency vulnerabilities scanned and patched

Authentication & Authorization:

• Strong API key generation process
• API key rotation procedures documented
• Rate limiting configured and tested
• Authorization checks implemented for all endpoints

Data Protection:

• TLS 1.3 enabled for all communications
• Database encryption at rest configured
• Sensitive data properly classified and protected
• Backup encryption implemented
• Log sanitization implemented

Infrastructure Security:

• Container security scanning completed
• Non-root user execution configured
• Network policies implemented
• Secrets management properly configured
• Security contexts applied to all pods

Monitoring & Incident Response:

• Security monitoring implemented
• Alerting rules configured
• Incident response procedures documented
• Emergency contacts updated
• Log retention policies configured

Ongoing Security Tasks:

• Daily security alert monitoring
• Weekly access log review
• Monthly API key rotation
• Quarterly security assessments
• Annual penetration testing

For security issues or questions:

• Security Team: security@scifind.com
• Emergency: +1-XXX-XXX-XXXX
• Bug Bounty: security-reports@scifind.com

• OWASP Top 10
• Go Security Guide
• Container Security Best Practices
• API Security Best Practices