The break-in with no broken window.
Most cyber attacks you can picture. A locked screen, a ransom note, an alarm going off. An infostealer is the opposite. It does not smash anything. It walks in quietly, copies your saved passwords and logins, and leaves without a trace. You carry on as normal. Then, days or weeks later, someone logs in as you and the damage starts. This is one of the fastest growing threats to small businesses, and most owners have never heard of it.
What an infostealer actually is
An infostealer is a small piece of malware with one job: quietly copy the useful things saved on your computer and send them to a criminal. Think of a pickpocket who does not take your wallet. They open it, photograph every card and password inside, slip it back, and you never feel a thing.
What they photograph is everything your browser remembers for you. The passwords you told it to save. The card details at the checkout. And the "keep me logged in" tokens that let someone skip the password and the security code entirely. All copied in seconds, then gone.
What it copies
Tap each one to see what it means for you.
The quiet part: it copies fast, then it waits
Here is the part that catches people out. The copying takes seconds. But the danger does not arrive with it. Your stolen logins get packaged up, sold on, and sit in criminal hands until someone decides to use them. Some infostealers even stay on the machine and keep copying, month after month, quietly topping up their haul.
There is no popup. No warning. No ransom note on day one. Everything looks fine, which is exactly the problem. Press play and watch how a single infection plays out over three weeks.
How it gets in without you noticing
Nobody clicks a button labelled "install malware." Infostealers arrive dressed as something you actually wanted.
Free or cracked software ▶
The number one way in. A "free" version of paid software, a game mod, a cracked tool. The program might even work as promised. The stealer simply rides along inside it.
Fake updates and download buttons ▶
A website warns that your browser or a plugin is out of date. The "update" is the malware. The same goes for the biggest, brightest "Download" button on a dodgy page.
Fake "prove you are human" pages ▶
A page tells you to confirm you are not a robot by pressing a few keys or pasting a line of text. Those keystrokes quietly run the malware in memory. This trick, known as ClickFix, exploded through 2025 and slips straight past most email filters because you run it yourself.
Phishing emails ▶
An attachment or link, often disguised as an invoice, a delivery note, or a message from a supplier you know. Open it, and the download begins.
Poisoned adverts and search results ▶
A paid advert or a top search result that points to a fake copy of a real, trusted program. You searched for the right thing and still landed on the wrong download.
The families doing the damage
Most infostealers are not built by the people using them. They are rented, like any other software, for around 200 dollars a month, complete with a control panel and customer support. This is called malware-as-a-service, and it means someone with almost no skill can run one. These are the names showing up most in 2026.
LummaC2 (Lumma) ▶
The biggest name for a long stretch. Police disrupted it in May 2025, and it was back within weeks. Known for a fast update cycle that keeps defeating browser protections.
Acreed / ACRStealer ▶
Surged to the top after Lumma was hit. Dangerous because it can hijack your live login sessions to walk past two-factor, then hands ready-made access straight to ransomware crews.
StealC (v2) ▶
Popular, cheap, and relaunched in 2025 as a rebuilt version designed to dodge detection and frustrate investigators trying to trace it.
Vidar ▶
A long-running, reliable stealer that keeps stepping into the top spot every time a bigger rival gets taken down.
Rhadamanthys ▶
A premium option known for clever evasion, for stealing document files, and for reading secrets out of screenshots. Its own servers were seized in late 2025, which tells you how much damage it was doing.
RedLine (still circulating) ▶
Taken down in October 2024, but the logins it stole are still bought and sold today. Old does not mean safe.
Mac is not safe either ▶
Atomic macOS Stealer and Banshee target Apple machines, aimed at developers, executives, and anyone assuming a Mac cannot be touched.
Why small businesses are the perfect target
Owners often think, we are too small to bother with. That belief is exactly why small businesses get hit. To the criminal, you are not a small business. You are a shortcut to a bigger one.
Here is the logic. Your laptop holds logins to your clients' systems, your suppliers' portals, your accountant, your bank. Bigger companies trust emails and logins that come from you. So an attacker does not need to break into the big target directly. They break into you, borrow your trusted access, and step across. This is called lateral movement, and small firms are the easiest first step. Watch how the pivot works.
One infected laptop at a small firm can quietly open the door to dozens of the companies it works with. That is why a stolen login from a five-person business can be worth more than the business itself.
Why it is so hard to catch
Traditional antivirus looks for files it already knows are bad. Infostealers are either brand new versions it has never seen, or they run entirely in memory and never leave a file to check. Either way, there is nothing on the list to match against.
There is no alarm to trip. The theft looks like an ordinary login. And because the strike comes days or weeks later, from somewhere else, most businesses never connect it back to that "free" download. By the time you notice, the login has already been used against you.
Catching this needs three things working together. Something watching what programs actually do, not just what they are called, so credential theft is spotted as it happens. Someone watching the dark web and stealer markets for your logins, so you know before they are used. And a team ready to act in the short window between theft and attack. Most small businesses have none of these. That gap is the whole opportunity.
How wide is your door?
Tick everything that is true. The higher the number, the wider your door is open to an infostealer.
- ✓Staff save passwords in their web browser
- ✓Some staff use personal laptops or phones for work
- ✓We rely on passwords, not passkeys, for important systems
- ✓We have no way to know if our logins appear on the dark web
- ✓No one watches what programs are doing on our devices in real time
- ✓We share logins or portals with suppliers or clients
GHOSTLINE closes the door infostealers walk through.
TRACE watches how programs behave on every device and shuts down credential theft the moment it starts, even from malware no antivirus has ever seen. SIGNAL watches the dark web and stealer markets for your logins, so a stolen password becomes a dead end instead of a way in. Together, that is the mature security team most small businesses cannot afford to hire.