Some malware announces itself. Infostealers do the opposite: they land, copy everything valuable out of your browser in seconds, and vanish. Saved passwords, autofill data, and session cookies all get bundled up and sold in bulk on criminal markets.
Security researchers keep tracing major breaches back to exactly this: an employee’s home computer caught an infostealer, and among the stolen goods was a work login. Sometimes the stolen session cookie lets attackers skip the password and the MFA prompt entirely, because the browser was already signed in.
Why small businesses should care
The credentials get sold in enormous batches, and buyers run them against everything. Your Microsoft 365 login, your bank, your line of business apps. You do not need to be targeted to be affected. You just need one person who saved a work password in a browser on an unprotected machine.
What helps
- Keep work logins off unmanaged machines. If home computers need work access, that is what secured setups and cloud PCs are for.
- Do not treat the browser as a password manager. A real password manager encrypts properly and does not hand everything over in one scoop.
- Shorten session lifetimes for sensitive apps. Stolen cookies expire worthless if sessions do not last for weeks.
- Watch for logins that make no sense. A sign in from a country your team has never visited is a flag worth catching the same hour, not the next quarter.
Curious whether your company credentials are already floating around in one of these dumps? Book a free consultation and we can check.