#system-hardening — Public Fediverse posts

I always remap my sshd daemon to listen to a non-standard port, to reduce a lot of noise. Which has worked fine for years. But every now and then there are attempts. All the #Linux kernel flaws found lately has made remote login attempts more interesting for attackers. And they scan much more broadly now than just port 22.

And that's why my second line of defence is to disallow remote root login - and also make use of the AllowGroups feature in sshd_config. Users granted remote access must be member of a specific group. And root is also excluded from this group.

That pays off these days. And this is a nice filter match for #fail2ban and similar tools

https://termbin.com/0cf6

I have 293 login attempts on "random users" since May 21. And 259 attempts as root.

#infosec #ssh #sshd #systemhardening #kernel

I always remap my sshd daemon to listen to a non-standard port, to reduce a lot of noise. Which has worked fine for years. But every now and then there are attempts. All the #Linux kernel flaws found lately has made remote login attempts more interesting for attackers. And they scan much more broadly now than just port 22.

And that's why my second line of defence is to disallow remote root login - and also make use of the AllowGroups feature in sshd_config. Users granted remote access must be member of a specific group. And root is also excluded from this group.

That pays off these days. And this is a nice filter match for #fail2ban and similar tools

https://termbin.com/0cf6

I have 293 login attempts on "random users" since May 21. And 259 attempts as root.

#infosec #ssh #sshd #systemhardening #kernel

Linux Security Auditing with Lynis

In this article, I cover how to use Lynis for Linux security auditing, system hardening, and practical vulnerability assessment.

🔗 https://denizhalil.com/2025/03/17/linux-security-auditing-with-lynis/

#CyberSecurity #LinuxSecurity #Lynis #SecurityAuditing #SystemHardening #BlueTeam #DevSecOps #InfoSec #Linux #ITSecurity #SecurityEngineering #DenizHalil

Linux Security Auditing with Lynis

In this article, I cover how to use Lynis for Linux security auditing, system hardening, and practical vulnerability assessment.

🔗 https://denizhalil.com/2025/03/17/linux-security-auditing-with-lynis/

#CyberSecurity #LinuxSecurity #Lynis #SecurityAuditing #SystemHardening #BlueTeam #DevSecOps #InfoSec #Linux #ITSecurity #SecurityEngineering #DenizHalil

Linux Security Auditing with Lynis

In this article, I cover how to use Lynis for Linux security auditing, system hardening, and practical vulnerability assessment.

https://denizhalil.com/2025/03/17/linux-security-auditing-with-lynis/

#CyberSecurity #LinuxSecurity #Lynis #SecurityAuditing #SystemHardening #BlueTeam #DevSecOps #InfoSec #Linux #ITSecurity #SecurityEngineering #DenizHalil

Linux Security Auditing with Lynis

In this article, I cover how to use Lynis for Linux security auditing, system hardening, and practical vulnerability assessment.

https://denizhalil.com/2025/03/17/linux-security-auditing-with-lynis/

#CyberSecurity #LinuxSecurity #Lynis #SecurityAuditing #SystemHardening #BlueTeam #DevSecOps #InfoSec #Linux #ITSecurity #SecurityEngineering #DenizHalil

Server Security Checklist — Essential Hardening Guide

Securing your servers isn’t optional — it’s your first line of defense against data breaches, ransomware, insider threats, and lateral movement. Use this checklist as a baseline for Linux, Windows, cloud, hybrid, or on-prem servers.

⸻

🔧 1. System & OS Hardening
• Keep OS & packages updated (apply security patches frequently).
• Remove / disable unused services & software.
• Enforce secure boot + BIOS/UEFI passwords.
• Disable auto-login and guest accounts.
• Use minimal OS images only (reduce attack surface).

⸻

🔐 2. Access Control
• Enforce strong passwords & MFA everywhere.
• Use RBAC & least privilege access.
• Disable root/Administrator login over SSH/RDP.
• Rotate credentials & keys regularly.
• Implement just-in-time access for privileged users.

⸻

🌐 3. Network Security
• Restrict inbound/outbound traffic via firewalls.
• Segment critical servers from general LANs/VLANs.
• Disable unused ports & protocols.
• Enable DoS/DDoS protection.
• Apply zero-trust network principles.

⸻

🔑 4. Secure Remote Access
• Use SSH key-based authentication (disable password login).
• Enforce VPN for admin access.
• Log & monitor all remote access sessions.
• Disable legacy protocols (Telnet, FTP, SMBv1).
• Require bastion/jump host for critical access.

⸻

📊 5. Logging & Monitoring
• Enable centralized logging (syslog / SIEM).
• Track failed login attempts & anomalies.
• Configure alerts for privilege escalation or config changes.
• Monitor log tampering.
• Retain logs securely for audits & forensics.

⸻

🔒 6. Data Protection
• Encrypt data at rest (LUKS, BitLocker, etc.).
• Encrypt data in transit (TLS 1.2+).
• Strict database access policies.
• Regular, offline, immutable backups.
• Test restore procedures (don’t assume backups work).

⸻

🔁 7. Application & Patch Management
• Keep middleware, frameworks, and apps patched.
• Delete default credentials & sample files.
• Enable code signing for software packages.
• Use secure coding practices (OWASP Top 10).
• Implement dependency scanning (Snyk, Trivy, etc.).

⸻

🛡️ 8. Malware & Intrusion Defense
• Deploy EDR/AV on endpoints.
• Enable IDS/IPS at network edge.
• Automatic vulnerability scans (schedule weekly/monthly).
• Monitor persistence techniques (cron, startup scripts).
• Block known malicious IP ranges & TLDs.

⸻

🏢 9. Physical & Cloud Security
• Restrict physical access to server racks/rooms.
• Enable provider security tools (AWS Security Groups, Azure NSG, IAM).
• Harden cloud images (CIS benchmarks).
• Review cloud logging & audit trails regularly.
• Disable unused cloud API keys / roles.

⸻

📜 10. Policy & Compliance
• Use CIS / NIST / ISO-27001 benchmarks.
• Track & document every access change.
• Force annual access reviews & key rotation.
• Perform regular security training for admins.
• Maintain disaster recovery & incident plans.

⸻

➕ Additional 5 Critical Controls (Advanced Hardening)

🧠 11. Privileged Access Management (PAM)
• Use jump hosts & session recording.
• Just-In-Time access for admins.
• Store keys in secure vaults (HashiCorp Vault, CyberArk).

🚨 12. Real-Time Threat Detection
• Use behavioral analytics → UEBA/XDR.
• AI-based anomaly detection recommended.
• Block suspicious IPs automatically.

🧪 13. Red Team & Pentesting
• Run regular internal pentests.
• Validate configuration weaknesses.
• Simulate phishing + lateral movement scenarios.

🧱 14. Container / VM Isolation
• Use AppArmor, SELinux, Seccomp profiles.
• Limit Docker socket access & root containers.
• Scan images before deployment.

📦 15. Automated Configuration Management
• Use IaC (Terraform, Ansible, Puppet) for repeatable and secure builds.
• Detect drift using compliance scanning.
• Version control all infrastructure.

⸻

🧠 Core Reminder

A server is only as secure as the team who maintains it.
Hardening isn’t one task — it’s an ongoing

#ServerSecurity #SystemHardening #InfoSec #CyberSecurity #BlueTeam
#DevSecOps #SysAdmin #ThreatDetection #AccessControl #NetworkSecurity
#LinuxSecurity #SecureArchitecture #RiskMitigation #SecurityChecklist
#CloudSecurity #InfrastructureSecurity #ZeroTrust #SecurityMonitoring

OpenGuardrails: A new open-source model aims to make AI safer for real-world use https://www.helpnetsecurity.com/2025/11/06/openguardrails-open-source-make-ai-safer/ #Artificialintelligence #systemhardening #cybersecurity #InfluxData #opensource #Don'tmiss #Features #Hotstuff #Hexnode #GitHub #News #CISO #LLMs

OpenGuardrails: A new open-source model aims to make AI safer for real-world use https://www.helpnetsecurity.com/2025/11/06/openguardrails-open-source-make-ai-safer/ #Artificialintelligence #systemhardening #cybersecurity #InfluxData #opensource #Don'tmiss #Features #Hotstuff #Hexnode #GitHub #News #CISO #LLMs

Linux Kernel Runtime Guard hits 1.0.0 with major updates and broader support https://www.helpnetsecurity.com/2025/09/08/linux-kernel-runtime-guard-lkrg-1-0-0-released/ #systemhardening #opensource #software #Linux #News

Linux Kernel Runtime Guard hits 1.0.0 with major updates and broader support https://www.helpnetsecurity.com/2025/09/08/linux-kernel-runtime-guard-lkrg-1-0-0-released/ #systemhardening #opensource #software #Linux #News

Systems don't age like wine.
They rot.

Keep them fresh - or embrace the decay.

#CyberSecurity #InfoSec #SystemHardening #DigitalDecay #ThreatModeling #DeadSwitchSignal

Systems don't age like wine.
They rot.

Keep them fresh - or embrace the decay.

#CyberSecurity #InfoSec #SystemHardening #DigitalDecay #ThreatModeling #DeadSwitchSignal

🛠 Forged in Fire: Why Ansible Speaks the DeadSwitch Language #DeadSwitch #Ansible #CyberSecurity #DevSecOps #LinuxHardening #VaultMinimal #GhostCompliance #AutomationWithIntent #Agentless #CyberGhost #SecureByDefault #InfrastructureAsCode #OpSec #SystemHardening #EmacsOrgMode #SilentAutomation

http://tomsitcafe.com/2025/04/25/%f0%9f%9b%a0-forged-in-fire-why-ansible-speaks-the-deadswitch-language/

🛠 Forged in Fire: Why Ansible Speaks the DeadSwitch Language #DeadSwitch #Ansible #CyberSecurity #DevSecOps #LinuxHardening #VaultMinimal #GhostCompliance #AutomationWithIntent #Agentless #CyberGhost #SecureByDefault #InfrastructureAsCode #OpSec #SystemHardening #EmacsOrgMode #SilentAutomation

http://tomsitcafe.com/2025/04/25/%f0%9f%9b%a0-forged-in-fire-why-ansible-speaks-the-deadswitch-language/

⚙️ The DeadSwitch Way: Emacs, Org Mode, and the Art of Ansible Rolecraft #Emacs #OrgMode #Ansible #DevOps #IaC #LinuxAutomation
#CyberGhostOps #DeadSwitchWay #InfosecTools #SystemHardening
#TechWriting #Magit #HackerTools #TrampMode #TomITCafe
#SilentOps #InfrastructureAsCode

http://tomsitcafe.com/2025/04/18/%e2%9a%99%ef%b8%8f-the-deadswitch-way-emacs-org-mode-and-the-art-of-ansible-rolecraft/

⚙️ The DeadSwitch Way: Emacs, Org Mode, and the Art of Ansible Rolecraft #Emacs #OrgMode #Ansible #DevOps #IaC #LinuxAutomation
#CyberGhostOps #DeadSwitchWay #InfosecTools #SystemHardening
#TechWriting #Magit #HackerTools #TrampMode #TomITCafe
#SilentOps #InfrastructureAsCode

http://tomsitcafe.com/2025/04/18/%e2%9a%99%ef%b8%8f-the-deadswitch-way-emacs-org-mode-and-the-art-of-ansible-rolecraft/

🐧 Before You Hack, You Must Understand: Why Linux Mastery Comes First #Linux #Cybersecurity #EthicalHacking #PenTesting #LinuxMastery #CyberGhost #HackerMindset #InfoSec #RootAccess #SystemHardening #CommandLine #LinuxSecurity #DeadSwitch

http://tomsitcafe.com/2025/04/06/%f0%9f%90%a7-before-you-hack-you-must-understand-why-linux-mastery-comes-first/

🐧 Before You Hack, You Must Understand: Why Linux Mastery Comes First #Linux #Cybersecurity #EthicalHacking #PenTesting #LinuxMastery #CyberGhost #HackerMindset #InfoSec #RootAccess #SystemHardening #CommandLine #LinuxSecurity #DeadSwitch

http://tomsitcafe.com/2025/04/06/%f0%9f%90%a7-before-you-hack-you-must-understand-why-linux-mastery-comes-first/

I tried Lynis this time, and it gave me clearer suggestions which I was able to act upon, such as installing critical apt tools, and change file permissions to certain files.

#Linux #cybersecurity #malware #systemhardening #tech

Day 12 done #adventofcyber2023 #adventofcyber #tryhackme #SystemHardening

Day 12 done #adventofcyber2023 #adventofcyber #tryhackme #SystemHardening

Full advisory from the #TCG about #CVE20231017 and #CVE20231017 here:https://trustedcomputinggroup.org/wp-content/uploads/TCGVRT0007-Advisory-FINAL.pdf

Article overview from #THN about the latest on the #TPM20 library flaws https://thehackernews.com/2023/03/new-flaws-in-tpm-20-library-pose-threat.html

#PatchYourSystems #SystemHardening

Full advisory from the #TCG about #CVE20231017 and #CVE20231017 here:https://trustedcomputinggroup.org/wp-content/uploads/TCGVRT0007-Advisory-FINAL.pdf

Article overview from #THN about the latest on the #TPM20 library flaws https://thehackernews.com/2023/03/new-flaws-in-tpm-20-library-pose-threat.html

#PatchYourSystems #SystemHardening