A free website security scan is a useful first check, but a green tick doesn’t mean your site is safe. Free scanners look at your website from the outside, the way a visitor would. They can spot visible malware, blocklist warnings and some outdated software. They can’t see hidden backdoors, rogue admin accounts or vulnerable plugins that haven’t been exploited yet. For that, you need a check from the inside.
Key takeaways
- Remote scanners only see the pages and files that are public.
- They’re good at catching visible malware, spam injections and blocklist status.
- They usually miss backdoors, malicious admin users and database infections.
- Sucuri found backdoors on 49% of hacked sites it cleaned, so “clean on the surface” isn’t enough.
- A proper audit checks files, the database, users, versions and server settings.
How does a free website security scan work?
A remote scanner visits your website, loads a set of pages and inspects the code it receives. It compares what it finds against lists of known malware, spam patterns and blocklists. Popular free tools include Sucuri SiteCheck and Google’s Safe Browsing site status check.
Because the scanner only sees what your server sends to visitors, it’s limited to the outside of the site.
What do free scans catch?
- Visible malware, such as malicious scripts injected into your pages.
- Spam injections, including hidden links and pharma or casino spam.
- Malicious redirects that send visitors elsewhere.
- Blocklist status with Google and some antivirus vendors.
- Some outdated software, when version numbers are publicly visible.
- Missing security headers and SSL problems.
That’s worth knowing. Google Safe Browsing protects over five billion devices a day (Google). If your site is flagged, most visitors will see a warning before they reach you.
What do free scans miss?
This is the important part. Remote scanners can’t see:
| What they miss | Why it matters |
|---|---|
| Backdoors in your files | Sucuri found backdoors on 49% of compromised sites. They let attackers return after a clean-up. |
| Malicious admin users | Found in 55% of infected databases Sucuri cleaned. |
| Database infections | Malware stored in the database may only appear to some visitors, or not at all. |
| Vulnerable plugins not yet exploited | Patchstack found 46% of 2025’s WordPress vulnerabilities had no fix at disclosure. |
| Conditional malware | Some infections only show to mobile users, first-time visitors or people arriving from Google. |
| Weak passwords and missing two-factor login | The most common way in, and invisible from outside. |
The figures come from Sucuri’s threat report and Patchstack’s 2026 report.
Why a green tick can give false confidence
Small businesses often underestimate their risk. auDA’s 2026 research found 38% of small businesses think they’re “too small to be targeted”, and those businesses were less likely to use multi-factor authentication (auDA). Attacks on websites are mostly automated. Bots scan millions of sites for known weaknesses, whatever their size.
A clean remote scan on a site with an outdated plugin is like a tidy house with an unlocked back door. Nothing looks wrong until someone walks in.
What should a proper security check include?
- File integrity: comparing core files against official copies and searching for injected code.
- Database review: looking for injected scripts, spam and suspicious options.
- User audit: listing every admin and checking each one is legitimate.
- Software versions: WordPress, plugins, themes and PHP, checked against known vulnerabilities.
- Login security: password policy, two-factor authentication and rate limiting.
- Server settings: file permissions, firewall rules and backups.
Our free security audit is a good first step. We check your site for common security problems, out-of-date software and blocklisting, then explain what we found in plain English.
For the deeper inside checks and ongoing protection, our Maintain & Protect plans scan for malware daily and come with a simple promise: hack-free, or we fix it free. Our website security monitoring keeps watching after the audit, as part of our website maintenance plans. Server-side protection comes with our secure web hosting.
What if a scan finds something?
Don’t just delete the flagged file. Infections usually have more than one part, and a partial clean-up often fails within days. Take a backup of the infected site for evidence, change all passwords and get a full clean-up. If customer data may have been exposed, you may have legal obligations. Our guide to handling a data breach explains them. For the broader picture, see our article on small business cyber security in Australia.
If a scan flags something, our checklist of warning signs your website has been hacked helps you confirm it, and our explainer on website security monitoring shows what ongoing checks catch that a one-off scan can’t.
Frequently asked questions
Are free website security scanners accurate?
They’re accurate about what they can see, which is the public side of your site. They can’t see inside your files or database, so a clean result isn’t a guarantee.
How often should I scan my website?
Daily is a good standard. Our Maintain & Protect plans scan for malware every day, update monthly and patch high-risk security flaws weekly.
Can a security plugin replace a scan?
A good security plugin scans from inside and adds a firewall. It still needs updating and someone to act on its alerts.
My scan says my site is blocklisted. What now?
Clean the site fully first, then request a review through Google Search Console. Asking for review before the clean-up usually fails.
Is a security audit worth it for a small business?
Yes. The average cybercrime report cost an Australian small business $56,600 in 2024-25, according to the ASD. An audit is a small price by comparison.
Sources
- 2023 Hacked Website and Malware Threat Report, Sucuri, June 2024
- State of WordPress Security in 2026, Patchstack
- Google Safe Browsing, Google
- Digital Lives of Australians 2026, auDA
- Annual Cyber Threat Report 2024-25, Australian Signals Directorate, October 2025