Most business owners assume their antivirus is quietly catching every threat that comes near their network. In reality, traditional antivirus works from a list of known bad software. If a piece of malware isn't on that list yet, or has been slightly altered to avoid detection, it can slip straight through and start running on a work PC without anyone noticing until the damage is done. For a small or medium business without a dedicated security team watching for odd behaviour, that gap can be the difference between a normal Tuesday and a very expensive, very disruptive week.
How traditional antivirus actually works
Conventional antivirus tools use what's called a "default allow" model. Every application is allowed to run unless it matches a known virus signature or is flagged as suspicious by behavioural analysis. This worked reasonably well when malware was slower to evolve, but attackers now generate new variants constantly, specifically to dodge signature-based detection. The result is a permanent game of catch-up: the antivirus vendor has to see a threat, analyse it, and push out an update before your business is protected against it. In the meantime, you're exposed.
This is particularly risky for SMEs, who are often targeted precisely because attackers assume smaller businesses have less robust defences than large enterprises.
The deny-by-default approach
ThreatLocker takes the opposite stance. Instead of trying to identify and block every bad program, it starts from a position where nothing is allowed to run unless it's been specifically approved. Only known, trusted applications and processes are permitted to execute on your devices. Everything else — malware, ransomware, unauthorised software, even well-meaning staff installing something they shouldn't — is blocked by default.
This closes the gap that traditional antivirus leaves open. It doesn't matter whether an attack is brand new, disguised, or fileless; if it isn't on the approved list, it simply doesn't run. There's no waiting for a vendor to catch up with the latest threat, because the protection isn't dependent on recognising the threat in the first place.
What this looks like day to day
- New software has to be approved before it can run, which stops shadow IT and unauthorised installs in their tracks.
- Ransomware that tries to execute is blocked immediately, rather than relying on detecting its behaviour after it's already started encrypting files.
- Scripts and macros commonly used in phishing attacks are prevented from running unless they're explicitly trusted.
Doesn't this slow the business down?
This is the most common objection, and it's a fair one. A poorly configured deny-by-default policy could, in theory, block legitimate tools your staff rely on. In practice, this is where proper setup and ongoing management make all the difference. ThreatLocker includes a "learning mode" that maps out what's already running across your business before any restrictions are switched on, so approved software is baked in from the start. After that, new requests are handled quickly through an approval workflow, rather than staff being locked out with no way forward.
Done properly, most employees never notice the difference in their day-to-day work. What they don't experience is a ransomware attack that started because someone opened the wrong attachment.
Why this matters for SMEs
Larger organisations often have layers of monitoring, dedicated security analysts, and budgets to match. SMEs typically don't, which makes prevention far more valuable than detection after the fact. A deny-by-default model shifts the burden away from constantly reacting to new threats and towards a much simpler question: is this piece of software something we trust, or not? That's a question a managed IT partner can answer and manage on your behalf, without you needing to become a cybersecurity expert yourself.
Ransomware and malware attacks are increasingly automated and don't discriminate by company size. If your current protection relies purely on recognising known threats, there's a meaningful gap in your defences that a deny-by-default approach is designed to close. Valetech Solutions deploys and manages ThreatLocker for businesses across Greater Manchester as part of a wider cybersecurity strategy, handling the setup, approvals and ongoing tuning so your team can work without friction. If you'd like to know whether your current setup would stand up to this kind of scrutiny, Get in touch with Valetech Solutions.