After years running ModSecurity + OWASP CRS on nginx, I migrated arleo.eu to a more modern stack: CrowdSec AppSec on OpenResty. The result is a tighter inline WAF architecture — better integrated, easier to maintain, and fully coherent with the rest of the security stack.

Why Drop ModSecurity?

ModSecurity v2 is in maintenance mode. Managing OWASP CRS rules on classic nginx generates friction: frequent false positives, logs that are hard to correlate with CrowdSec, and a configuration spread across multiple tools with no unified view.

Why SRI?

When your site loads resources from a third-party CDN — FontAwesome, Mermaid, Animate.css — you’re trusting an external party you have no control over. If jsdelivr.net gets compromised, or if a supposedly immutable version is silently mutated, your site can become an attack vector.

Subresource Integrity (SRI) solves this cleanly: every <link> or <script> tag carries an integrity="sha256-…" attribute that the browser verifies before executing the resource. If the hash doesn’t match, the browser blocks the load.

CSP nonces and CDN caching are incompatible by design. On a Hugo static site, SHA-256 hashes are the native approach: computed at build time, stable across requests, and fully compatible with Cloudflare caching.

TL;DR

The LoveIt theme’s typewriter animation (TypeIt) stopped working on the home after adding Mermaid diagrams to posts. Cause: a #id-1 DOM selector shared between both libraries. When Mermaid finds an orphan block in a home summary, its initialization crashes, and the JS init chain stops before reaching TypeIt. Fix: add `

TL;DR

The Cloudflare plugin in hugo-mcp v2.0 implements 3 cache purge modes (full, partial, smart). The partial mode computes the linked URLs to invalidate (canonical + sitemap + RSS + listing + home) to preserve 95% of the CDN cache on every modification. Concretely: 6 URLs purged instead of wiping everything. This post details the computation, the pitfalls, and why smart became the default.

⚡ TL;DR

A security stack audit on the homelab NUC reveals redundant double WAF inspection: ModSecurity + OWASP CRS load 11,872 rules into memory despite SecRuleEngine Off, running in parallel with CrowdSec AppSec which already covers the same surface. After removing the ModSecurity nginx module and five other targeted fixes, nginx drops from ~520 MB to ~27 MB PSS. Same security, memory footprint divided by 20.

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🏗️ Architecture Before the Audit

The security stack had six stacked layers: