Compromised credentials are work logins that have leaked out and landed where criminals can buy or trade them, usually on dark web marketplaces. If an employee’s username and password show up there, assume someone will try them on your email, VPN, and cloud apps. Soon.
The fix is quick. Reset the password, end active sessions, confirm multi-factor authentication (MFA) is on, and look for signs the account was already used.
Why the rush? The 2026 Verizon Data Breach Investigations Report found that half of ransomware victims had a credential or infostealer exposure in the 95 days before the attack. That’s a warning window. Most businesses never see it.
Are your team’s logins already out there?Run a free dark web scan with our Houston team.
Free Dark Web ScanHow Do Logins End Up on the Dark Web?
Rarely through some dramatic hack of your own company. They leak out through everyday channels, then get bundled and resold.
⛓Someone Else’s Data Breach
An employee signs up for a webinar or a software trial with their work email. That site gets breached. If they reused their work password there (people do, constantly), the attacker now has a working pair.
✉Phishing
A convincing email asks someone to “verify” their Microsoft 365 account. They type their password into a fake page, and it goes straight to the attacker. According to the 2026 DBIR, phishers are also having more luck with voice calls and text messages than with email.
⚠Infostealer Malware
Infostealers are small programs that quietly grab saved passwords, browser cookies and session tokens from an infected computer. The haul gets packaged into “logs” and sold.
Session cookies are the nasty part. They can let an attacker skip the login step entirely, MFA included.
$Access Brokers
Some criminals do nothing but collect access and sell it to ransomware groups. Flare’s summary of the 2026 DBIR puts typical prices at about $700 for a standard user account and close to $1,300 for an admin account. Cheap for a key to your network.
Why Compromised Credentials Do So Much Damage
A stolen password looks like a normal login. No malware to catch, no sketchy attachment to block. The attacker just signs in.
The 2026 DBIR found credential abuse at some stage in 39% of breaches. Exploited vulnerabilities did overtake stolen credentials as the top way attackers first get in this year, but once they’re inside, credentials are everywhere. Attackers use them to hop between systems and read email.
Credential Stuffing
Attackers take huge lists of leaked username and password pairs and fire them automatically at other sites, thousands of attempts at a time. It works for one reason. People reuse passwords. A leak from someone’s personal shopping account can open their work email if the password matches.
Business Email Compromise
Once inside a mailbox, attackers often just watch for a while. They learn who pays the invoices and how your vendors write. Then they send a well-timed request to change bank details, from a real account, which makes it very hard to spot.
The money is only part of the cost. Our piece on revenue and reputation gets into the rest.
What to Do About Compromised Credentials
- Reset the password. New, unique, not used anywhere else.
- End all active sessions. Signing the user out everywhere kills any stolen session cookies.
- Confirm MFA is on. If it wasn’t, turn it on now. Authenticator apps beat text codes, and phishing-resistant options like security keys or passkeys are stronger still.
- Check sign-in history for logins from unfamiliar places, devices or times.
- Review mailbox rules. Attackers love adding hidden forwarding rules that copy email out. Delete anything you don’t recognize.
- Reset any other accounts that shared the same password.
- Scan the device. If an infostealer is the likely source, the computer needs cleaning, or the new password will leak the same way the old one did.
- Write down what you found. Your cyber insurer may want a record of the exposure and how you handled it.
See signs the account was actually used? Then it’s an incident, not a password reset. Our help desk support team can walk your staff through the steps or handle them directly.
How Do You Stop the Next Leak?
You can’t stop other companies from getting breached. You can make a leaked password close to useless.
🔐Make MFA Non-Negotiable
MFA is the biggest single barrier between a stolen password and a breach. Turn it on for email, remote access, cloud apps, and every admin account. Cyber insurers ask about it on almost every application now, so you’ll need it anyway.
🗝Use a Password Manager
A password manager makes a unique password for every account realistic, and unique passwords are what break credential stuffing. We cover how this works for teams in password management.
⛔Block Known-Breached Passwords
NIST’s digital identity guidelines (SP 800-63B) tell organizations to check new passwords against a blocklist that includes passwords from past breaches. Many identity platforms do this automatically. Nobody gets to pick a password attackers already have.
🎓Train Your People
Most leaks start with a click. Regular security awareness training and phishing simulations teach staff to spot a fake login page and report it instead of typing into it.
👁Keep Watching
A one-time scan tells you about today. Leaks don’t stop, though (new breach dumps and infostealer logs surface all the time). Ongoing monitoring alerts you when new company logins appear, so you can reset them before anyone uses them. Here’s how dark web monitoring protects your business between scans.
How Function4 Helps
We’ve helped Houston businesses with their technology since 2012. Our cybersecurity services pull together dark web scanning, endpoint protection, MFA rollout and staff training. And through managed IT services, we keep an eye out for exposed credentials, reset accounts fast and keep the controls in place that stop a leaked password from turning into a breach.
Frequently Asked Questions
What are compromised credentials?
Logins someone else has gotten hold of. Usually that’s an email or username plus a password, picked up through a data breach, a phishing page, malware or plain password reuse. Once exposed, they tend to get sold or shared on dark web forums and tried against other accounts.
How do passwords end up on the dark web?
Mostly through other companies’ data breaches, phishing pages and infostealer malware. Criminals collect the stolen logins, bundle them into lists and sell or trade them. A password can leak through a site you signed up for years ago and forgot about, even if your own systems were never touched.
What is credential stuffing?
An automated attack. Criminals take leaked username and password pairs and try them on lots of other websites, betting that people reused passwords. Unique passwords and MFA stop most of it.
Is it dangerous if my email is on the dark web?
On its own, not very. An exposed address mostly means more phishing and spam, which is annoying but manageable if your staff know what to look for. The real risk starts when a password, a session cookie or other personal data shows up alongside it. So find out exactly what was exposed and when. Then reset any matching passwords, sign out of active sessions and make sure MFA is turned on for that account.
Can someone get into my account without my password?
Yes, sometimes. Infostealer malware can grab the session cookies that keep you signed in, and attackers can reuse them to skip the login step (MFA included, in some cases). That’s why ending active sessions and cleaning the infected device matter just as much as changing the password.
How do I check if my email is on the dark web?
For a single address, free services like Have I Been Pwned will tell you whether it showed up in a known breach. A business needs more than that. A professional dark web scan checks your whole domain at once and shows which employees are exposed.
What should I do if my password is on the dark web?
Change it right away, to something new and unique, and change it anywhere else you used it. Then sign out of all active sessions, turn on MFA and look over recent sign-in activity. For a work account, tell IT so they can check for mailbox rules or other signs of misuse.
Does dark web monitoring remove my information?
No. Leaked data can’t realistically be pulled back once it’s out. Monitoring works as an early warning, so you can reset passwords before anyone uses them.
How often should a business scan for leaked credentials?
Ideally, all the time. New breaches and infostealer logs keep surfacing, so a once-a-year check misses most of the risk. At minimum, scan quarterly and before every cyber insurance renewal. For any business running on email and cloud apps, ongoing monitoring with alerts is the safer bet.
Does MFA protect against stolen passwords?
Mostly. It blocks the bulk of attacks that rely on a stolen password alone. Session theft and MFA fatigue attacks can still get past weaker methods, which is why security keys and passkeys are worth the switch.
Find Out What’s Already Exposed
Compromised credentials are one of the cheapest ways into a business. They’re also one of the easiest to shut down once you know about them. Want a clear picture of your exposure and a plan to close it?
Get your free technology assessment.Prefer to talk first? Call (346) 270-2334.
