New Access Security Installed

New Access Security Installed: A Comprehensive Guide to Infrastructure Hardening

1. INTRODUCTION

When Reddit users spotted an “intruder” in a homelab server rack photo last month, the sysadmin community immediately recognized the dual nature of modern security challenges. While the feline interloper was harmless, the incident underscores a critical truth: unauthorized access remains the #1 threat to self-hosted infrastructure.

In 2024, 68% of homelab breaches originate from misconfigured access controls according to SANS Institute research. Whether you’re securing Docker containers, Kubernetes clusters, or bare-metal servers, implementing robust access security isn’t optional—it’s existential.

This guide delivers battle-tested security hardening techniques refined through enterprise deployments and adapted for homelab environments. You’ll learn:

• Modern access control frameworks beyond basic SSH keys
• Threat prevention strategies that stop 99% of automated attacks
• Container-specific security measures Docker doesn’t enable by default
• Monitoring systems that detect anomalies before they become breaches

By combining infrastructure-as-code principles with military-grade security practices, we’ll transform your environment into a fortress—without sacrificing operational efficiency.

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2. UNDERSTANDING ACCESS SECURITY

What is Modern Access Control?

Contemporary access security combines three layers:

1. Authentication (Prove identity via SSH keys, MFA, certificates)
2. Authorization (Define precise permissions with RBAC/ABAC)
3. Audit (Log all access attempts with immutable records)

Evolution of Access Security

The field has evolved dramatically:

Era	Approach	Limitations
1990s	Passwords	Brute-force vulnerable
2000s	SSH Keys	No expiration/rotation
2010s	MFA	Phishing risks
2020s+	Certificate-based + Contextual Auth	Requires PKI infrastructure

Critical Components

1. Zero Trust Architecture: Never trust, always verify
2. Just-In-Time Access: Temporary elevated privileges
3. Network Policies: Microsegmentation for containers
4. Behavioral Analysis: Detect anomalous activity

Real-World Impact

When Cloudflare implemented certificate-based access:

• Reduced breach surface by 83%
• Eliminated SSH key sprawl
• Achieved PCI DSS compliance

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3. PREREQUISITES

Hardware Requirements

• x86_64 or ARMv8+ CPU
• 2+ cores dedicated to security services
• 4GB RAM minimum for analysis workloads

Software Dependencies

# Core security stack components
sudo apt install -y \
  fail2ban=0.11.2 \
  wireguard=1.0.20210914 \
  auditd=3.0.7 \
  libpam-google-authenticator=20191231-1

Network Pre-Checks

1. Confirm no open ports except 443/80:

   sudo ss -tulpn | grep -vE '(127.0.0.1|:::443|:::80)'
   

2. Verify reverse path filtering:

   sysctl net.ipv4.conf.all.rp_filter
   # Should return 1
   

Security Baseline

Before implementation:

• Disable root SSH access
• Remove unused packages (apt list --installed)
• Confirm UFW/iptables default deny policy
• Backup existing configurations

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4. INSTALLATION & SETUP

Step 1: Certificate-Based SSH Access

Replace vulnerable keys with X.509 certificates:

# Generate CA (air-gapped machine only)
ssh-keygen -t ed25519 -f access-ca -C "ACCESS_CA_$(date +%Y%m%d)"

# Sign user certificate (valid 8h)
ssh-keygen -s access-ca -I "user_$(whoami)" \
  -V +8h -n "$(whoami)" id_ed25519.pub

Step 2: Container Hardening

Create a Docker security profile:

# daemon-security.json
{
  "userns-remap": "default",
  "no-new-privileges": true,
  "iptables": true,
  "live-restore": true,
  "userland-proxy": false
}

Apply with:

sudo cp daemon-security.json /etc/docker/daemon.json
sudo systemctl restart docker

Step 3: Network Microsegmentation

Implement Calico network policies:

apiVersion: projectcalico.org/v3
kind: NetworkPolicy
metadata:
  name: frontend-policy
spec:
  selector: role == 'frontend'
  ingress:
    - action: Allow
      protocol: TCP
      destination:
        ports: [443, 80]
  egress:
    - action: Allow
      protocol: TCP
      destination:
        selector: role == 'backend'
        ports: [3306]

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5. CONFIGURATION & OPTIMIZATION

SSH Hardening Checklist

# /etc/ssh/sshd_config
Protocol 2
PermitRootLogin no
MaxAuthTries 3
LoginGraceTime 30
ClientAliveInterval 300
HostbasedAuthentication no
IgnoreRhosts yes
PermitEmptyPasswords no
X11Forwarding no
AllowTcpForwarding no
PermitTunnel no
AllowAgentForwarding no

Fail2Ban Advanced Configuration

# /etc/fail2ban/jail.d/nginx.conf
[nginx-botsearch]
enabled  = true
port     = http,https
filter   = nginx-botsearch
logpath  = /var/log/nginx/access.log
maxretry = 2
findtime = 1h
bantime  = 1d

Performance vs Security Tradeoffs

Setting	Security Gain	Performance Impact
SSH CBC Ciphers	High	None
TLS 1.3 Only	Medium	Low (-3% TPS)
Container Profiling	High	Med (-8% CPU)

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6. USAGE & OPERATIONS

Daily Access Review

# Check authentication attempts
sudo journalctl _TRANSPORT=audit --since "24h ago" | grep USER_LOGIN

# Container access audit
docker events --filter 'event=exec' --since 24h

Automated Policy Enforcement

# Check for privileged containers
docker ps --format "table $CONTAINER_ID\t$CONTAINER_NAMES\t$CONTAINER_STATUS\t$CONTAINER_IMAGE" \
  | awk '$4 ~ /privileged/ {print "ALERT: Privileged container "$2}'

# Verify certificate validity
find /etc/ssh/user_certs/ -name "*.pub" -exec ssh-keygen -Lf {} \; | grep Valid

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7. TROUBLESHOOTING

Common Issues & Solutions

Problem: SSH Certificate Expiration

# Renew before expiry
ssh-keygen -s /path/to/ca -I "renewal_$(date +%Y%m%d)" -V +8h user_key.pub

Problem: Overly Restrictive Network Policies

# Temporary audit mode
calicoctl patch globalnetworkpolicy default -p '{"spec":{"doNotTrack":true}}'

Problem: Fail2Ban False Positives

# /etc/fail2ban/filter.d/nginx-custom.conf
[Definition]
failregex = ^<HOST> .* "(GET|POST|HEAD) \/?(admin|wp-login) HTTP.*" 403
ignoreregex = .*\.(googlebot|bingbot)\.com

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8. CONCLUSION

Implementing modern access security transforms your infrastructure from a vulnerable target into a hardened environment that deters 98% of automated attacks (SANS 2024). By combining certificate-based authentication, network microsegmentation, and behavioral analysis, you’ve created multiple defensive layers that protect even when one component fails.

Next Steps:

1. Implement WireGuard for encrypted management access
2. Explore OpenPolicyAgent for granular RBAC
3. Automate certificate rotation with Hashicorp Vault

Security isn’t a one-time installation—it’s an ongoing process of refinement. Stay vigilant, monitor relentlessly, and remember: even the cutest intruders deserve a secure environment.

External Resources:

• NIST SSH Hardening Guide
• CIS Docker Benchmark
• Zero Trust Architecture (NSA)