Compromised Credentials | What They Are, How They’re Stolen, and How to Detect Them Before Attackers Do

Compromised credentials are usernames, passwords, or other login details that have fallen into an attacker’s hands through a phishing email, a data breach , or malware quietly harvesting them from an infected device. They can now be used to break into your accounts without your knowledge.

Once a credential is compromised, it doesn’t just disappear into the void; it’s typically packaged, sold, or shared on dark web marketplaces and criminal forums , where attackers can buy and reuse it long after the original breach makes headlines. That gap between compromise and discovery is exactly what makes credentials so dangerous.

According to IBM, breaches involving stolen or compromised credentials take an average of 292 days to identify and contain, longer than any other attack type.