FRAUD SCENARIO LIBRARY

Credential Stuffing 

Credential stuffing is a type of cyberattack where attackers use large sets of stolen usernames and passwords—often from data breaches on unrelated websites—to gain unauthorized access to user accounts on other platforms.

How Does Credential Stuffing Work?

Attackers obtain leaked credentials from the dark web or past breaches.

Data Collection

Attackers obtain leaked credentials from the dark web or past breaches.

Attackers obtain leaked credentials from the dark web or past breaches.

Automation

They use bots or scripts to rapidly attempt logins across multiple sites.

If users have reused passwords, attackers can successfully access accounts.

Account Takeover

If users have reused passwords, attackers can successfully access accounts.

Credential Stuffing to Filing

Stopping Attacks with Fingerprint + Unit21

A fraud analyst receives an alert: multiple failed logins are occurring across different accounts from what appears to be the same device. The trigger? Fingerprint detects identical device/browser signatures attempting to access hundreds of accounts - a clear sign of credential stuffing in progress.

1

Fingerprint Detection: Device Intelligence Triggers Early Warning

Fingerprint’s passive browser/device tracking identifies repeated login attempts from a single fingerprint across multiple user accounts. This anomaly is automatically shared with Unit21 as a high-fidelity signal.

2

Custom Rules Fire in Unit21

Within Unit21, custom rules are configured to escalate login attempts that combine failed authentications and shared Fingerprint identifiers. These alerts immediately flag compromised accounts for analyst review.

3

Network Analysis Identifies Account Takeover Campaign

Using graph-based analysis, analysts visualize a web of accounts linked by device fingerprinting, shared IPs, and behavioral similarities - quickly revealing a coordinated credential stuffing campaign.

4

Risk Rating Adjustments & Watchlist Screening

Affected accounts are rerated with elevated customer risk scores. Some match prior watchlists - enabling further prioritization for action and internal escalation.

5

AI Agent Summarizes Activity & Suggests Filing

Unit21’s AI Agent auto-summarizes key behaviors, links to publicly known attack patterns, and pre-populates a suspicious activity narrative. Analysts finalize and file a SAR or STR with one click, enabling rapid compliance and regulator notification.

Prevention Tips for Credential Stuffing

  • Encourage unique passwords and multi-factor authentication (MFA).
  • Monitor for unusual login behavior.
  • Use bot detection and rate-limiting tools.
FREQUENTLY ASKED QUESTIONS

Credential Stuffing

Why is credential stuffing a growing threat?
What makes systems vulnerable to credential stuffing attacks?
How does password reuse contribute to credential stuffing?
Can poor anomaly detection increase the risk?
What are the potential impacts of a successful credential stuffing attack?
How does bot traffic from credential stuffing affect business operations?
Why is multi-factor authentication critical in prevention?

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