Hacked Without Knowing It: Infostealers Are a Mid-Market Issue

Infostealers are malware that read passwords, saved credentials and sessions from a computer and send them to third parties. The device keeps running; nobody sees a warning. The stolen data later ends up in collections that are traded online. The company often never finds out, and it never makes the news either.

Why this concerns mid-sized companies

The way onto the computer is unspectacular: a fake download, a tool from an untrusted source, an attachment that looks like an invoice. Often it is a device also used privately, with business logins saved in the browser. Session cookies are particularly sensitive: whoever holds them can take over an existing login without a password and sometimes without a second factor. The attack does not target a specific company. It takes whatever it finds.

What we check

We want to know which companies in our region are affected without suspecting it. To do so, we check automatically and in batches whether credentials with company domains appear in such data sets. Every result is recorded, whether found or not. That turns a gut feeling into a reliable overview. If there is a hit, we inform the affected company personally.

What helps if you suspect a breach

There is no such thing as 100% security. What matters is being able to act quickly: change affected passwords, end active sessions, switch on multi-factor authentication and have the device checked. The order matters: a new password helps little while a stolen session is still valid. If these steps are prepared, no time is lost when it counts.

Three takeaways

1. No alarm does not mean no incident. Infostealers work invisibly, and the true picture only emerges when you check.
2. Check regionally, inform personally. A systematic check turns scattered hints into a clear basis for action.
3. Preparation beats perfection. Knowing your response steps limits the damage and keeps you able to act.