CYBER SECURITY – Page 2

Paperless-NGX Setup: Installation, Security, and NGINX Integration

When I read about paperless-ngx, I was immediately drawn to the idea of having all my documents indexed (via OCR) and centrally stored. With a proper tagging system, exporting my documents for my annual tax declaration should only take seconds.

Bogon Defense: Integrating Dynamic IP Blacklists into Suricata’s Reputation System

Bogon networks are IP address ranges that should never appear on the public internet, as they are either reserved or unassigned. Blocking these ranges is a fundamental and highly effective security measure. While this can be done with simple firewall rules, integrating the blocklist directly into the Suricata IP Reputation system is far more performant.

Suricata AF-Packet: Resolving VirtIO Non-Functionality via Checksum Offload Disablement

This article documents a two-part process: successfully upgrading Suricata to version 7 on Debian Bookworm and solving a critical stability issue required to run the AF-Packet IPS mode with high-performance VirtIO NICs in a virtual machine. Without this specific configuration, the IPS failed to function.

Automating IPS: Real-Time Suricata Rule Generation via Fail2ban Hook

In my last posts, I established a central syslog hub feeding Fail2ban and demonstrated Suricata as an intrusion prevention system (IPS). This final piece connects the two: feeding Suricata with the ban results from Fail2ban by creating a dynamic, external rule file.

Suricata Alert Analysis: Tuning Rules and Promoting Detection to Prevention

This is a follow-up to my last post in which I set up Suricata as an IPS. This article demonstrates how to effectively work with the Suricata engine—specifically, how I analyze its log output, silence unnecessary alerts, and promote specific detection rules to prevention rules.

Suricata IPS: Building a Transparent Network Defense Layer with AF-Packet Bridging

Suricata functions as a powerful engine for Network Intrusion Detection and Prevention (IDS/IPS). This guide demonstrates how to set up Suricata as a transparent Intrusion Prevention System (IPS) within a KVM environment by replacing the kernel bridge with the high-performance AF-Packet mechanism.

Automated Defense: Building a Central Log Hub for Fail2ban and External Firewall Integration

A very light-weight and efficient approach for consolidating logs centrally is by using rsyslog. My virtual machines all use rsyslog to forward their logs to a dedicated internal virtual machine, which acts as the central log hub. A fail2ban instance on this hub checks all incoming logs and sends a block command to an external firewall—a process helpful for automated security.

ZFS Data Migration: Encrypting Existing Volumes with zfs send and zfs recv

Encrypting previously unencrypted data, such as a legacy ZFS pool, requires a reliable migration strategy. The most robust way to achieve this is by using the powerful ZFS data stream mechanism: zfs send and zfs recv.

The core procedure is simple: create a snapshot, transfer this snapshot, and receive it at a new, encrypted destination.

ZFS Encryption: Mitigating Physical Attacks with Remote Key Management

This article documents the design and implementation of an external key management solution for ZFS encryption. This approach utilizes a custom PHP service to serve encryption keys on demand, specifically designed to mitigate physical and system-level compromises where local keys would fail. This deep dive explores the security architecture, the self-written PHP proof-of-concept (PoC), and the critical security caveats of building a custom Key Management System (KMS).

Inside Amavisd-new: Advanced Features for Intelligent Mail Filtering

I guess that most people use amavisd-new together with spamassassin and for example ClamAV. Probably a few more use features like DKIM verification and signing with amavis. However, there are some features which aren’t found in the usual howtos. Here are some of them.