commands/sysadmin/linux-desktop/security/posture-diagnostics/security-posture-check.md

You are conducting a comprehensive security posture evaluation for this Linux desktop system.

Your Task

Perform a thorough security assessment of the system and provide a detailed report with actionable recommendations.

Assessment Areas

1. Firewall Status

• Check if UFW (Uncomplicated Firewall) or iptables is active
• Review firewall rules and policies
• Identify any concerning open ports

2. System Updates

• Check for available security updates
• Verify automatic update configuration
• Review update history for critical patches

3. User Account Security

• List user accounts and their privileges
• Check for accounts with sudo access
• Identify any accounts without passwords or weak configurations
• Review SSH key configurations

4. SSH Security

• Check if SSH is running
• Review SSH configuration (/etc/ssh/sshd_config)
• Verify key-based authentication settings
• Check for root login permission
• Review allowed authentication methods

5. Running Services

• List all active services
• Identify unnecessary services that could be disabled
• Check for services listening on external interfaces

6. File Permissions

• Check critical system files (/etc/passwd, /etc/shadow, /etc/sudoers)
• Review permissions on home directories
• Identify world-writable files in system directories

7. Antivirus/Malware Protection

• Check if ClamAV or other antivirus is installed
• Verify if definitions are up to date
• Check recent scan history

8. Security Packages

• Verify installation of: fail2ban, apparmor, aide, rkhunter, lynis
• Check their configuration and status

9. Network Security

• Review listening ports and services
• Check for unusual network connections
• Verify network configuration security

10. Audit Logs

• Check if auditd is running
• Review recent authentication logs
• Look for failed login attempts
• Check for suspicious sudo usage

Output Format

Provide your findings in the following structured format:

SECURITY POSTURE ASSESSMENT
Generated: [timestamp]

=== SUMMARY ===
Overall Security Level: [Critical/Poor/Fair/Good/Excellent]
Critical Issues Found: [number]
Warnings: [number]
Recommendations: [number]

=== CRITICAL ISSUES ===
[List any critical security problems that need immediate attention]

=== WARNINGS ===
[List security concerns that should be addressed]

=== CURRENT PROTECTIONS ===
[List active security measures in place]

=== RECOMMENDATIONS ===
[Prioritized list of security improvements]

=== DETAILED FINDINGS ===
[Detailed breakdown by assessment area]

Important Notes

• Use sudo when necessary to access system files and configurations
• Be thorough but focus on actionable findings
• Prioritize issues by severity
• Provide specific commands for remediation where applicable
• Consider the desktop/workstation context (not a server)