The Scale of the Credential Stuffing Problem
There are over 24 billion leaked credential pairs in circulation. Automated tools can test millions of username/password combinations per hour across hundreds of target sites simultaneously. The success rate is low — typically 0.1 to 2% — but when you're testing millions of credentials, even a fraction of a percent yields thousands of compromised accounts.
The attacks have gotten smarter too. Modern stuffing tools rotate through residential proxy networks, randomize request timing, mimic real browser fingerprints, and solve CAPTCHAs using ML services that cost pennies per solve.
Detection Beyond Rate Limiting
Simple rate limiting catches simple attacks. But sophisticated credential stuffing bypasses rate limits by distributing requests across thousands of IPs.
1-SEC's Auth Fortress uses behavioral analysis instead. It watches for impossible travel — login attempts from New York and Tokyo within 5 minutes. It detects password spray patterns where one password is tried across many accounts. It tracks MFA fatigue attacks where an attacker repeatedly triggers MFA notifications hoping the user will approve out of annoyance.
Stolen Token Detection
Session tokens stolen via XSS or malware get used from different IPs, user agents, and geolocations than the original session. Auth Fortress maintains a behavioral fingerprint for each session and flags tokens that suddenly change context.
OAuth and Consent Phishing
Attackers don't always need passwords. OAuth consent phishing tricks users into granting access to malicious applications. Auth Fortress monitors OAuth token grants for suspicious scopes, unfamiliar client IDs, and consent patterns that deviate from normal usage.
Building a Real Defense
Layer your authentication defenses. Rate limiting catches the dumb attacks. Behavioral analysis catches the smart ones. Impossible travel catches stolen sessions. MFA fatigue detection catches social engineering. And session fingerprinting catches token theft.
1-SEC runs all of these simultaneously from a single binary, correlating signals across modules. A credential stuffing campaign that also triggers network anomalies from botnet IPs gets escalated as a compound threat — because that's exactly what it is.