Securing user accounts

Introduction
- What?
- Why?
- How?
Configuring sudo
Disabling root access
Locking home directories
- Red Hat and CentOS
- Debian and Ubuntu
  - useradd
  - adduser
Configuring password complexity
- Pwquality
- Resources
Configuring other password requirements
Dangers of the lxd group
- Resources

Audit services

Introduction
- What?
- Why?
- How?
Auditing system services with systemctl
- Candidates for removal
- Stop and disable
Auditing network services with netstat
- Resources
Auditing network services with nmap
- Port states
- Scan types

Firewalls

Introduction
- What?
- Why?
- How?
- Notes
iptables
UFW
- Installation
- Control
- Usage
  - SSH
  - Nginx HTTP
  - Nginx HTTPS
  - Logging
  - OpenVPN
NFTables
FirewallD
FireHOL
- Installation
- Configuration (example)
Packet filtering
- Configuration resources
Fail2ban
SSHguard
Web Application Firewall WAF
- mod_security
Port spoofing

Encryption technologies

Introduction
- What?
- Why?
- How?
- Notes
GNU Privacy Guard
- Using GPG
- Encrypting files with GPG
  - Symmetric
  - Asymmetric
OpenVPN
strongSwan
- Configuration resources
Installing SSH
Harden ssh server
- Configuration file
- Additional security
Key management
Jumping hosts

Virtual network computing (VNC)

Introduction
- What?
- Why?
- How?
- Notes
TigerVNC
TightVNC
Securing sessions
- TLS
- X509
- SSH

Access control

Introduction
- What?
- Why?
- How?
Discretionary access control (DAC)
Access control lists (ACL) and shared directory management (SDM)
Mandatory access control (MAC)
- SELinux
- AppArmor

Public key infrastructure (PKI)

Introduction
- What?
- Why?
- How?
- Notes
Problems
Internal PKI
Pluggable Authentication Modules (PAM)
- Passwords
- SSH
  - Deny access
  - Allow access
- SASL
Let’s Encrypt
TLS/SSL

Logfiles

Introduction
- What?
- Why?
- How?
- Notes
Syslog
log commands
Path of a common intruder
- Scenario
- Important events for reconstructing an attack
Logrotate
- Installation
- Configuration
Centralised logging

Guards! Guards!

Introduction
- What?
- Why?
- How?
- Notes
Samhain
Maltrail

Incidents

Introduction
- What?
- Why?
- How?
- Notes
Preventing incidents
Using git for configuration management
Implementing a backup plan
- Incremental backups
- Simple script
Using bootable recovery media

Troubleshooting

Overview
- What?
- Why?
- How?
Authentication error
Connection refused

Hardening Linux server

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