Linux Secure Ops is a working notebook for sysadmins who run Debian and Ubuntu boxes in the wild and want to keep them out of the news. We publish reproducible hardening playbooks, post-incident write-ups, and benchmark-aligned configs we actually use on our own fleet — not warmed-over checklists scraped from a 2019 blog. Every command has been pasted into a real shell, every sysctl tweak measured, every IDS rule load-tested before it hits the page.
Noble Numbat changed enough defaults that the old 16.04/20.04 hardening guides now produce broken servers. AppArmor 4, unprivileged user namespaces restrictions, and the new Livepatch client all need fresh treatment. Our playbook walks the full CIS Ubuntu 24.04 Benchmark Level 1 and Level 2 controls, then layers on what CIS leaves out — disabling kernel.unprivileged_bpf_disabled, scoping systemd-resolved, and locking down cloud-init on imaged hosts.
We pay particular attention to the controls that break things quietly: USBGuard policies that lock out KVM consoles, nftables rulesets that survive a netplan reapply, and SSH MaxStartups values that won't lock you out during an Ansible run across 200 hosts. Where a control is theatre, we say so.
The intrusion-detection landscape in 2026 looks nothing like it did five years ago. CrowdSec has matured into a credible Fail2Ban replacement with a community blocklist, Wazuh 4.9 ships a usable agent for Debian-family hosts, and nftables sets make dynamic blocking far cheaper than the iptables hash-tables of old. We benchmark these tools head-to-head on a real SSH-and-Nginx edge node, measure false-positive rates against actual traffic, and show the exact bouncer wiring for Caddy, HAProxy, and bare nftables.
We also cover what nobody likes to admit: most small fleets don't need a SIEM, they need a journald pipeline into Loki with three good alert rules. We share those rules.
A clean Lynis hardening index above 90 is achievable on stock Ubuntu in an afternoon if you know which warnings to trust. We catalogue every sysctl we set — what it actually does at the kernel level (with links to kernel.org sysctl docs), what breaks when you set it wrong, and which ones are placebo. The same treatment applies to auditd rule sets, PAM stacks, and the perpetually misunderstood /etc/login.defs.
Browse our latest articles below for the current week's deep dives, incident retros, and config snippets you can paste into a terminal tonight.
How Linux kernel live patching works in 2026 with kpatch, Ubuntu Livepatch, and TuxCare KernelCare. Install commands, comparison table, and audit tips for zero-downtime CVE fixes.
Wolfi vs Distroless vs Alpine base images for 2026 Linux workloads, with CVE benchmarks, apko and cosign pipeline snippets, and real migration examples for Node.js and Python services.
OpenBao 2.5 vs HashiCorp Vault in 2026: licensing under BUSL vs MPL 2.0, what's free in OpenBao, a real migration recipe from Vault CE 1.14.x, Kubernetes patterns with ESO, and a hardening checklist from a pentester's view.
Deploy Keylime continuous remote attestation on Linux with TPM 2.0: registrar, verifier, Rust agent, IMA runtime policies, and revocation webhooks in 2026.
Auto-unlock LUKS2 volumes at boot using Tang and Clevis NBDE. Covers install, sss threshold pins with TPM2, safe key rotation, and boot troubleshooting for headless Linux servers.
VEX is the layer between your SBOM and your scanner that says this CVE doesn't apply to us, and here's why. Walks through OpenVEX, CSAF VEX, vexctl, Trivy --vex, Grype match exclusions, and the CI pipeline pattern I run on every Linux build.
Kata Containers and gVisor both sandbox Linux containers but use very different mechanisms. This 2026 guide compares their isolation models, performance overhead, Kubernetes RuntimeClass setup, and when to pick each runtime for production workloads.
A practical walkthrough of Linux memory forensics with Volatility 3 in 2026: capturing RAM with AVML or LiME, building ISF symbol tables, running the plugin chain that catches LKM, LD_PRELOAD, and eBPF rootkits, and mapping each detection back to a hardening control.
Use BPF LSM (KRSI) to write dynamic kernel security policies in eBPF. Enable it on Linux 6.x, ship your first enforcement program, and stage audit-to-enforce rollouts safely.
Build, sign, and enroll Unified Kernel Images on Linux: ukify, sbctl, systemd-boot, and TPM2 PCR policies for a measured, tamper-evident Secure Boot chain in 2026.
Compare structured outputs and function calling across OpenAI, Anthropic, and Gemini in 2026. Includes Python code, vendor matrix, and eval metrics that catch the failures schema validation misses.
SPIFFE and SPIRE give Linux workloads short-lived, verifiable identities (SVIDs) for mTLS and JWT auth, replacing long-lived API keys and secrets.
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