Every plugin on this list has a genuinely free tier — no trial, no credit card, no time limit. What differs is how much of the actual job that free tier does. A few of these will scan your site, tell you it's infected, and then ask for payment before they'll remove anything. Others give you real, complete protection for free and simply hold back convenience features. Knowing which is which before you install matters more than the install-count numbers do.
Quick comparison
| Plugin | Active installs | What's actually free | The catch |
|---|---|---|---|
| Wordfence | 5,000,000+ | Malware scanning, firewall, login/brute-force protection | Free tier's threat feed lags 30 days behind Premium's real-time updates |
| Sucuri | 600,000+ | Malware & integrity scanning, basic hardening | The cloud WAF and human cleanup team are a separate paid service |
| All-In-One Security (AIOS) | 1,000,000+ | Extensive firewall and hardening rules, login lockdown, file-change monitoring | No malware scanner at all in the free version |
| MalCare | 200,000+ | Weekly malware scan, firewall, vulnerability alerts | Free tier detects malware but can't remove it — cleanup is paid |
| Jetpack Protect | 100,000+ | Daily vulnerability scanning against WPScan's 60,000+ CVE database | No firewall or malware scanning at all in the free plugin |
| Kadence Security | 700,000+ | Password strength, two-factor auth, brute-force login protection | Login-hardening focused — light on malware and vulnerability scanning |
| SecurynAI | — | Firewall, malware scan, vulnerability alerts, hardening, and plain-English explanations, together | Newer, with a smaller track record than the decade-plus players above |
Wordfence
The default most people reach for first, and for good reason — the free tier is a real firewall plus a real malware scanner, not a teaser. The tradeoff is timing, not features: Wordfence's free Threat Defense Feed delivers new firewall rules and malware signatures 30 days after Premium subscribers get them. For a vulnerability being actively exploited the week it's disclosed, that 30-day window is exactly when most of the damage happens.
Sucuri
The free plugin covers malware and file-integrity scanning plus basic hardening — genuinely useful on its own. What it doesn't include for free is Sucuri's signature offering: the cloud WAF and the human team who manually clean up a compromised site. Those live behind Sucuri's paid platform plans, so the free plugin is really a detection layer, not the full product.
All-In-One Security (AIOS)
One of the most feature-dense free security plugins available — firewall rules, login lockouts, file-change monitoring, database and user hardening, all with no paywall. The one thing conspicuously missing: a malware scanner. AIOS free will tell you a core file changed, but it won't scan your site for injected malware the way Wordfence, Sucuri, or MalCare do.
MalCare
Free MalCare runs a weekly malware scan, a firewall, and vulnerability alerts — solid detection coverage. The catch is sharp and worth knowing up front: the free tier finds malware but cannot remove it. If a scan turns something up, cleanup requires upgrading to a paid plan. That's a meaningfully different promise than "free malware protection" might suggest.
Jetpack Protect
A narrow, well-executed free tool: daily vulnerability scanning powered by WPScan's database of 60,000+ known WordPress vulnerabilities, checking your installed core, plugins, and themes against it. It does exactly that one thing and does it for free with no setup. It doesn't run a firewall or scan for malware at all — those require Jetpack's paid Security plan, so Protect is realistically a companion to another tool, not a full replacement for one.
Kadence Security
Focused on the login layer specifically — enforced password strength, two-factor authentication, and brute-force lockouts. If weak logins are your actual risk (a common one, since credential stuffing accounts for a large share of WordPress compromises), this free tier addresses it directly. It's lighter than the others here on malware scanning and vulnerability tracking, so it tends to get paired with something else rather than used alone.
SecurynAI
Where the others each cover one or two pieces for free and hold the rest back, SecurynAI's free tier bundles firewall, malware scanning, vulnerability alerts, and hardening together — plus a plain-English explanation of what each finding means, which none of the others attempt at any price. The honest tradeoff: it's the newest plugin on this list, without the decade-plus production track record that Wordfence or Sucuri can point to.
So which free plugin should you actually use?
- Want the single most battle-tested free firewall: Wordfence — just budget for the 30-day-delayed threat feed as a real limitation, not a footnote.
- Your main gap is hardening, not scanning: AIOS or Kadence Security.
- You want vulnerability scanning specifically, layered on top of something else: Jetpack Protect.
- You're fine finding problems yourself and cleaning them up manually: MalCare's free tier.
- You want firewall, scanning, vulnerability alerts, and hardening together, explained in plain language, without combining two or three plugins: SecurynAI.
Worth saying plainly: a lot of real setups run two free plugins together precisely because no single free tier here covers everything — AIOS for hardening plus Jetpack Protect for vulnerability scanning is a genuinely common, sensible combination. Just be aware that overlapping firewalls occasionally conflict, so test any new combination on staging before trusting it in production.
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