Network Security Control Reviews

# AWS Network Security Controls Comprehensive Review **Production VPC (vpc-0010c25f3b0eb8863) & Development VPC (vpc-0627541bf1d62805c)** **Review Date:** November 24, 2025 **Scope:** Security Groups & Network ACLs --- ## 1. Executive Summary ### Security Posture Overview - **Total Security Groups Reviewed:** 8 (4 Production + 4 Development) - **Total Network ACLs Reviewed:** 4 (2 Production + 2 Development) - **Total Rules Analyzed:** 41 ### Issue Summary by Severity | Severity | Count | Resources Affected | |----------|-------|-------------------| | 🚨 **Critical** | 2 | Dev-Database-SG, Production-Application-SG | | ⚠️ **High** | 3 | Dev-Application-SG, Production-NACL, Development-NACL | | ℹ️ **Medium** | 2 | Default security groups (both VPCs) | ### Overall Assessment The Production VPC demonstrates better security controls with proper tier-based segmentation and restricted access patterns. However, **critical vulnerabilities exist in the Development VPC**, particularly SSH exposure on database servers. Cross-VPC connectivity is enabled at the Network ACL level, creating potential segmentation violations that require immediate attention. --- ## 2. 🚨 Critical Issues (Severity: Critical) ### Critical Issue #1: Public SSH Access to Database Server **Affected Resource:** `sg-0e3ae3e6560ba3262` (Dev-Database-SG) **VPC:** vpc-0627541bf1d62805c (Development) **Environment:** Development / Network-B #### Rule Details ``` Type: Ingress Protocol: TCP Port: 22 (SSH) Source: 0.0.0.0/0 Description: "WARNING: Overly permissive SSH access" ``` #### Security Risk - **Impact:** CRITICAL - Direct database compromise possible - **Exposure:** Database tier exposed to Internet-wide SSH brute force attacks - **Attack Surface:** Any attacker can attempt authentication against production database infrastructure - **Compliance Violation:** Violates PCI-DSS 1.3.1, SOC 2, and NIST 800-53 AC-3 #### Immediate Remediation Steps 1. **IMMEDIATE ACTION** - Remove the 0.0.0.0/0 SSH rule from sg-0e3ae3e6560ba3262 2. Create a dedicated bastion/jump host security group 3. Update Dev-Database-SG to only allow SSH from bastion SG: ``` Source: sg-<bastion-host-sg-id> Port: 22 Protocol: TCP ``` 4. Implement AWS Systems Manager Session Manager as SSH alternative (no inbound ports required) 5. Enable VPC Flow Logs to audit existing SSH connection attempts 6. Rotate all database credentials immediately (assume compromise) --- ### Critical Issue #2: Overly Broad Internal Network Access **Affected Resource:** `sg-06153643a91d79c86` (Production-Application-SG) **VPC:** vpc-0010c25f3b0eb8863 (Production) **Environment:** Production / Network-A #### Rule Details ``` Type: Ingress Protocol: TCP Port: 443 (HTTPS) Source: 10.0.0.0/8 Description: "Allow HTTPS from internal network" ``` #### Security Risk - **Impact:** HIGH to CRITICAL - Permits access from unintended networks - **Exposure:** The /8 CIDR block (10.0.0.0/8) encompasses 16,777,216 IP addresses - **Current VPCs:** Production (10.0.0.0/16) and Development (10.1.0.0/16) only use 131,072 IPs combined - **Blast Radius:** Opens application tier to potential future networks or misconfigurations #### Immediate Remediation Steps 1. Replace the 10.0.0.0/8 CIDR with specific allowed sources: ``` # Option A: Restrict to Production VPC only Source: 10.0.0.0/16 # Option B: If cross-VPC access needed, be explicit Source: 10.0.0.0/16 (Production) Source: 10.1.0.0/16 (Development) ``` 2. Review application architecture to determine if cross-VPC access is required 3. If Development should NOT access Production apps, remove 10.1.0.0/16 entirely 4. Document approved source networks in security group descriptions 5. Implement tag-based security group references where possible: ``` Source: sg-<web-tier-sg-id> instead of CIDR blocks ``` --- ## 3. ⚠️ High-Risk Issues (Severity: High) ### High Issue #1: Unencrypted HTTP Exposed to Internet **Affected Resource:** `sg-06dbcc866e55ac136` (Dev-Application-SG) **VPC:** vpc-0627541bf1d62805c (Development) #### Rule Details ``` Type: Ingress Protocol: TCP Port: 80 (HTTP) Source: 0.0.0.0/0 Description: "WARNING: Overly permissive HTTP access" ``` #### Security Risk - **Impact:** HIGH - Man-in-the-middle attacks, credential theft, data interception - **Data Exposure:** All traffic unencrypted and vulnerable to eavesdropping - **Session Hijacking:** Cookies and session tokens transmitted in clear text - **Compliance:** Violates PCI-DSS requirement 4.1 (encrypt transmission of cardholder data) #### Remediation Steps 1. Remove HTTP (port 80) ingress rule entirely 2. Add HTTPS (port 443) rule if not present: ``` Source: 0.0.0.0/0 Port: 443 Protocol: TCP Description: "Public HTTPS access" ``` 3. Configure application load balancer or web server to redirect HTTP→HTTPS 4. Implement HSTS (HTTP Strict Transport Security) headers 5. Consider adding ALB with AWS ACM certificates for TLS termination --- ### High Issue #2: Cross-Environment Network Connectivity **Affected Resources:** - `acl-0af0e5957e726b65a` (Production-NACL) - `acl-061a0331327c18e7e` (Development-NACL) #### Rule Details - Production NACL ``` Type: Ingress/Egress (Bidirectional) Rule Number: 150 Protocol: All (-1) Source/Destination: 10.1.0.0/16 (Development VPC) Action: ALLOW ``` #### Rule Details - Development NACL ``` Type: Ingress/Egress (Bidirectional) Rule Number: 150 Protocol: All (-1) Source/Destination: 10.0.0.0/16 (Production VPC) Action: ALLOW ``` #### Security Risk - **Impact:** HIGH - Environment isolation violated - **Lateral Movement:** Compromised Development resources can reach Production - **Testing Risks:** Development code/changes can affect Production systems - **Compliance Violation:** Violates separation of duties and environment isolation principles - **Incident Scope:** Security incidents in Development automatically impact Production #### Remediation Steps 1. **Assess Business Requirements:** Determine if cross-VPC communication is genuinely needed 2. **If NOT Required:** ``` # Remove rules 150 from both NACLs aws ec2 delete-network-acl-entry --network-acl-id acl-0af0e5957e726b65a --rule-number 150 --ingress aws ec2 delete-network-acl-entry --network-acl-id acl-0af0e5957e726b65a --rule-number 150 --egress aws ec2 delete-network-acl-entry --network-acl-id acl-061a0331327c18e7e --rule-number 150 --ingress aws ec2 delete-network-acl-entry --network-acl-id acl-061a0331327c18e7e --rule-number 150 --egress ``` 3. **If REQUIRED:** Implement strict least-privilege access: ``` # Replace "allow all protocols" with specific requirements # Example: Allow only HTTPS from Dev to Prod API Rule: 150 Protocol: TCP (6) Port: 443 Source: 10.1.0.0/16 Destination: 10.0.x.x/32 (specific API server IP) ``` 4. Use VPC Peering with route table restrictions instead of broad NACL rules 5. Implement Transit Gateway with route domain isolation for better control 6. Enable VPC Flow Logs to monitor actual cross-VPC traffic patterns --- ### High Issue #3: Unrestricted Egress from Application Tier **Affected Resource:** `sg-06153643a91d79c86` (Production-Application-SG) **VPC:** vpc-0010c25f3b0eb8863 (Production) #### Rule Details ``` Type: Egress Protocol: All (-1) Port: All Destination: 0.0.0.0/0 ``` #### Security Risk - **Impact:** MEDIUM to HIGH - Data exfiltration risk - **Command & Control:** Compromised instances can communicate with attacker infrastructure - **No Visibility:** Malware can establish outbound connections without restriction - **Compliance Gap:** Fails to implement "default deny" egress policy #### Remediation Steps 1. Identify actual egress requirements through VPC Flow Log analysis 2. Replace "allow all" egress with specific rules: ``` # Example restrictive egress rules - Port 443 to specific API endpoints - Port 5432/3306 to database security group - Port 443 to AWS service endpoints (S3, DynamoDB, etc.) ``` 3. Use VPC Endpoints for AWS services (S3, DynamoDB, SSM) to avoid Internet egress 4. Implement AWS Network Firewall or NAT Gateway with allow-list 5. Enable GuardDuty for detection of malicious egress patterns --- ## 4. Network Segmentation Analysis ### 4.1 Cross-VPC Connectivity Assessment #### Current State Both Production and Development VPCs have **bidirectional unrestricted connectivity** enabled at the Network ACL level: | Direction | Source Network | Destination Network | Protocol | Status | |-----------|---------------|---------------------|----------|--------| | Dev → Prod | 10.1.0.0/16 | 10.0.0.0/16 | ALL | ⚠️ ENABLED | | Prod → Dev | 10.0.0.0/16 | 10.1.0.0/16 | ALL | ⚠️ ENABLED | #### Security Implications - **Environment Boundary Violation:** Development and Production should be logically isolated - **Blast Radius Expansion:** Security incidents in one environment cascade to the other - **Compliance Risk:** Many frameworks require environment separation (PCI-DSS, SOC 2) - **Testing Safety:** No protection against Development changes affecting Production #### Observed Architecture Pattern Despite NACL-level connectivity, Security Group rules show **proper tier-based segmentation**: - Web tier accepts Internet HTTPS - Application tier accepts from Web/Internal networks - Database tier accepts only from Application tier **Recommendation:** Remove NACL cross-VPC rules. If connectivity is required, implement at Security Group level with specific source/destination pairs and ports. --- ### 4.2 Segmentation Violations Identified #### Violation #1: Development Database Exposed to Internet - **Finding:** SSH port open to 0.0.0.0/0 on database tier - **Expected:** Database tier should be accessible only from application tier - **Severity:** CRITICAL - **Evidence:** sg-0e3ae3e6560ba3262 ingress rule #### Violation #2: Production Application Accepts Overly Broad Internal Traffic - **Finding:** Application tier accepts HTTPS from entire 10.0.0.0/8 range - **Expected:** Should accept only from Web tier SG or specific VPC CIDRs - **Severity:** CRITICAL - **Evidence:** sg-06153643a91d79c86 ingress rule #### Violation #3: Unrestricted Egress from All Tiers - **Finding:** All security groups allow egress to 0.0.0.0/0 on all protocols - **Expected:** Egress should be limited to required destinations - **Severity:** HIGH - **Evidence:** All SG egress rules --- ### 4.3 Instance-Level vs Subnet-Level Controls Comparison | Control Type | Implementation | Scope | Pros | Cons | Use Case | |--------------|---------------|-------|------|------|----------| | **Security Groups** | Instance-level | Stateful firewall per ENI | Granular, easy to reference other SGs | Requires assignment to each instance | Primary access control | | **Network ACLs** | Subnet-level | Stateless firewall per subnet | Broad subnet protection, deny rules | Less granular, must allow return traffic | Defense-in-depth, DDoS protection | #### Current Implementation Assessment **Production VPC:** - ✅ Security Groups: Well-structured with proper tier references - ⚠️ Network ACLs: Overly permissive cross-VPC rules (rule 150) - 📊 Pattern: **Security Groups provide primary controls, NACLs add minimal value** **Development VPC:** - ⚠️ Security Groups: Critical misconfigurations (SSH, HTTP exposure) - ⚠️ Network ACLs: Permissive cross-VPC rules mirror Production issues - 📊 Pattern: **Neither layer provides adequate protection** #### Recommendations 1. **Security Groups:** Primary enforcement mechanism - Use tag-based SG references instead of CIDR blocks - Implement least-privilege access patterns - Remove default security groups from use 2. **Network ACLs:** Defense-in-depth and DDoS protection - Remove cross-VPC allow-all rules - Add explicit deny rules for known-bad sources - Keep rules minimal and subnet-aligned - Example use cases: - Deny all inbound SSH except from bastion subnet - Rate-limit HTTPS to web tier subnets - Block specific threat intelligence IOCs --- ## 5. Recommendations ### 5.1 Immediate Actions (Within 24 Hours) #### Priority 1: Remove Critical Exposures 1. ⏰ **Remove public SSH access** from Dev-Database-SG (sg-0e3ae3e6560ba3262) 2. ⏰ **Restrict Production Application SG** from 10.0.0.0/8 to specific VPC CIDRs 3. ⏰ **Rotate database credentials** in Development environment (assume compromise) 4. ⏰ **Enable VPC Flow Logs** for both VPCs immediately #### Priority 2: Enable Monitoring ```bash # Enable VPC Flow Logs aws ec2 create-flow-logs \ --resource-type VPC \ --resource-ids vpc-0010c25f3b0eb8863 vpc-0627541bf1d62805c \ --traffic-type ALL \ --log-destination-type cloud-watch-logs \ --log-group-name /aws/vpc/flowlogs # Enable GuardDuty aws guardduty create-detector --enable ``` --- ### 5.2 Short-Term Actions (Within 1 Week) #### Segmentation Improvements 1. **Evaluate Cross-VPC Requirements** - Document legitimate use cases for Production↔Development communication - If none exist, remove NACL rules 150 from both VPCs - If required, replace with specific protocol/port rules 2. **Implement Bastion Architecture** ``` Create: sg-bastion (jump host security group) - Ingress: Your office/VPN CIDR on port 22 only - Egress: Production/Dev VPC CIDRs on port 22 only Update: All database and application SGs - Replace 0.0.0.0/0 SSH with source: sg-bastion ``` 3. **Fix HTTP→HTTPS Migration** - Remove port 80 from Dev-Application-SG - Deploy Application Load Balancer with SSL/TLS termination - Configure HTTP-to-HTTPS redirect rules - Implement HSTS headers 4. **Implement Restrictive Egress** - Analyze 30 days of VPC Flow Logs for egress patterns - Create allow-list of required egress destinations - Update all SG egress rules to deny-by-default - Use VPC Endpoints for AWS services --- ### 5.3 Best Practices Recommendations #### Security Group Design Patterns ``` ✅ GOOD: Reference other security groups sg-web → sg-app (source: sg-web) sg-app → sg-db (source: sg-app) ❌ BAD: Overly broad CIDR blocks sg-app (source: 10.0.0.0/8) ✅ GOOD: Specific protocols and ports TCP port 5432 from sg-app ❌ BAD: "Allow all" rules ALL traffic from 0.0.0.0/0 ``` #### Naming and Tagging Standards Implement consistent resource naming: ```yaml Security Groups: Format: {Environment}-{Tier}-{Purpose}-SG Example: Production-Database-PostgreSQL-SG Tags Required: - Environment: Production|Development|Staging - Tier: Web|Application|Database|Management - Network: Network-A|Network-B - Owner: team-name - CostCenter: department-code ``` #### Defense-in-Depth Strategy Implement multiple layers of controls: 1. **Network ACLs** - Subnet-level protection 2. **Security Groups** - Instance-level primary control (stateful) 3. **Host Firewalls** - OS-level protection (iptables/Windows Firewall) 4. **Application Firewalls** - WAF for web applications 5. **Identity & Access** - IAM roles and policies #### Network Segmentation Model ``` Internet ↓ [Public Subnet - Web Tier] ↓ (only HTTPS/443) [Private Subnet - Application Tier] ↓ (only DB ports from sg-app) [Private Subnet - Database Tier] ↓ (no direct Internet access) NAT Gateway (for updates only) ``` #### Security Group Reference Pattern Replace CIDR-based rules with SG references: ```python # Instead of: CidrIp: "10.0.1.0/24" # Use: SourceSecurityGroupId: "sg-web-tier" Description: "Allow from Web tier security group" ``` #### Monitoring and Alerting ```yaml CloudWatch Alarms: - UnauthorizedSSHAttempts (from VPC Flow Logs) - SecurityGroupChanges (from CloudTrail) - UnusualEgressTraffic (GuardDuty findings) - CrossVPCTraffic (VPC Flow Logs analysis) AWS Config Rules: - restricted-ssh (no 0.0.0.0/0 on port 22) - restricted-common-ports (no public access to DB ports) - vpc-flow-logs-enabled - guardduty-enabled-centralized ``` --- ## 6. ✅ Positive Findings ### Properly Configured Security Controls #### 6.1 Production VPC Security Strengths ✅ **Proper Tier-Based Segmentation** - Web tier (sg-0aa1fbf8078f24d98): Accepts HTTPS from Internet appropriately - Application tier (sg-06153643a91d79c86): Properly references internal networks - Database tier (sg-01d4dec8340b585eb): Correctly restricted to application SG only ✅ **Security Group Referencing** ``` Production-Database-SG ingress rules: - PostgreSQL (5432) from sg-06153643a91d79c86 (Application SG) - MySQL (3306) from sg-06153643a91d79c86 (Application SG) ``` This pattern prevents unauthorized database access even if network boundaries change. ✅ **Comprehensive Tagging** Both VPCs implement consistent tags: - Environment classification (Production/Development) - Network designation (Network-A/Network-B) - Tier identification (Web/Application/Database) - Descriptive names for all resources ✅ **Network ACL Strategy** Custom NACLs (Production-NACL, Development-NACL) implemented with: - Explicit HTTPS allow rules - Default deny for unmatched traffic - Proper rule precedence (100, 150, 200, etc.) --- #### 6.2 Development VPC Security Strengths ✅ **Database Access Control** Development database SG properly references application tier: ``` Dev-Database-SG ingress: - PostgreSQL (5432) from sg-06dbcc866e55ac136 (Dev-Application-SG) - MySQL (3306) from sg-06dbcc866e55ac136 (Dev-Application-SG) ``` ✅ **HTTPS-Only Web Tier** Dev-Web-SG accepts only HTTPS (port 443) from Internet, not HTTP. ✅ **Consistent Architecture** Development mirrors Production's three-tier architecture, making it suitable for testing production-like scenarios. --- ### Key Architectural Patterns Observed #### Pattern 1: Multi-Tier Application Architecture Both VPCs correctly implement: ``` Internet → Web Tier → Application Tier → Database Tier ``` #### Pattern 2: Security Group Chain of Trust Database tiers trust application tiers through SG references rather than IP ranges, providing: - Automatic updates when instances scale - No IP address management overhead - Clear dependency visualization #### Pattern 3: Network Isolation via Tags Resources properly tagged for: - Environment separation (Production vs Development) - Network segmentation (Network-A vs Network-B) - Cost allocation and ownership tracking --- ### Summary of Positive Security Posture Despite the critical issues identified, the underlying architecture demonstrates **security-conscious design**: 1. ✅ Proper use of security group referencing 2. ✅ Three-tier architecture with clear separation 3. ✅ Custom Network ACLs for additional control 4. ✅ Comprehensive resource tagging 5. ✅ Web tier appropriately exposed via HTTPS **The main issues are configuration oversights rather than fundamental architectural problems**, making remediation straightforward and low-risk. --- ## 7. Compliance and Risk Matrix | Finding | CIS AWS Benchmark | PCI-DSS | SOC 2 | NIST 800-53 | Risk Score | |---------|-------------------|---------|-------|-------------|------------| | Public SSH to Database | 5.2 | 1.3.1, 2.2.1 | CC6.6 | AC-3, AC-4 | 9.5/10 | | Overly Broad Internal Access | 5.2 | 1.3.4 | CC6.1 | AC-3 | 8.5/10 | | Unencrypted HTTP | 5.2 | 4.1 | CC6.7 | SC-8 | 8.0/10 | | Cross-VPC All Traffic | 5.1 | 1.2.1 | CC6.6 | AC-4 | 7.5/10 | | Unrestricted Egress | 5.3 | 1.3.4 | CC6.1 | AC-4 | 7.0/10 | --- ## 8. Appendix: Resource Inventory ### Production VPC (vpc-0010c25f3b0eb8863) **CIDR:** 10.0.0.0/16 **Tags:** Environment=Production, Network=Network-A #### Security Groups | Group ID | Name | Rules | Purpose | |----------|------|-------|---------| | sg-0aa1fbf8078f24d98 | Production-Web-SG | 2 | Web tier - public HTTPS | | sg-06153643a91d79c86 | Production-Application-SG | 2 | Application tier - internal services | | sg-01d4dec8340b585eb | Production-Database-SG | 3 | Database tier - restricted access | | sg-017cc87bf5646936e | default | 2 | ⚠️ Unused default SG | #### Network ACLs | ACL ID | Name | Type | Rules | Associated Subnets | |--------|------|------|-------|-------------------| | acl-0af0e5957e726b65a | Production-NACL | Custom | 7 | subnet-069fa3952c2dc480d | | acl-0d4825db5ac1b1547 | (default) | Default | 4 | (none) | --- ### Development VPC (vpc-0627541bf1d62805c) **CIDR:** 10.1.0.0/16 **Tags:** Environment=Development, Network=Network-B #### Security Groups | Group ID | Name | Rules | Purpose | |----------|------|-------|---------| | sg-0c426974459a1f4f6 | Dev-Web-SG | 2 | Web tier - public HTTPS | | sg-06dbcc866e55ac136 | Dev-Application-SG | 2 | Application tier - internal services | | sg-0e3ae3e6560ba3262 | Dev-Database-SG | 4 | Database tier - ⚠️ SSH exposed | | sg-0917ccabaee2e6c13 | default | 2 | ⚠️ Unused default SG | #### Network ACLs | ACL ID | Name | Type | Rules | Associated Subnets | |--------|------|------|-------|-------------------| | acl-061a0331327c18e7e | Development-NACL | Custom | 7 | subnet-021cf5ff3f40f76e5 | | acl-05afc42db64c7a8a5 | (default) | Default | 4 | (none) | --- ## 9. Review Metadata **Review Performed By:** AWS Network Security Controls Review Tool **Tool Version:** nsc-review v1.0 **Data Source:** AWS API (live configuration) **Review Scope:** - Production VPC: vpc-0010c25f3b0eb8863 - Development VPC: vpc-0627541bf1d62805c **AWS Region:** us-east-1 **AWS Account ID:** 605821131877 **Total Resources Analyzed:** 8 Security Groups, 4 Network ACLs, 41 Rules --- ## 10. Next Steps & Action Plan ### Week 1: Critical Remediation - [ ] Remove public SSH from Dev-Database-SG - [ ] Restrict Production-Application-SG to specific CIDRs - [ ] Enable VPC Flow Logs for both VPCs - [ ] Enable AWS GuardDuty - [ ] Rotate Development database credentials ### Week 2: High-Priority Fixes - [ ] Evaluate and document cross-VPC requirements - [ ] Remove HTTP from Dev-Application-SG - [ ] Deploy Application Load Balancer with SSL - [ ] Implement bastion host architecture - [ ] Create restrictive egress rules ### Week 3: Best Practices Implementation - [ ] Implement VPC Endpoints for AWS services - [ ] Deploy AWS Config rules for continuous compliance - [ ] Set up CloudWatch alarms for security events - [ ] Document security group design standards - [ ] Train team on security best practices ### Ongoing: Continuous Improvement - [ ] Monthly security group reviews - [ ] Quarterly penetration testing - [ ] Regular VPC Flow Log analysis - [ ] Security group automation via Infrastructure as Code - [ ] Incident response plan testing --- **END OF REPORT**