Account takeover fraud prevention with trust scoring
Published · Updated
8 min read
Why static rules miss account takeover, and how continuous trust scoring stops fraud without adding friction for genuine customers.
Account takeover starts with a stolen secret
Most account takeover fraud begins with a credential the attacker did not have to break: a reused password, a phished one time code, a session cookie lifted from malware. The login itself looks perfectly valid, which is why rule based fraud detection often sees nothing wrong.
Removing the shared secret removes the primary attack path. Passkeys are bound to a device and to the origin they were created for, so a phishing page cannot replay them and a leaked database cannot reveal them.
Fraud prevention needs signals, not rules
A single rule (block logins from a new country) either fires constantly for travellers or misses an attacker using a residential proxy. Fraud teams end up tuning thresholds against each other.
Authiun weighs device posture, passkey presence, network and IP reputation, geo velocity, behavioural rhythm and history together into one trust score from 0 to 100. The score, not any single rule, decides whether a payment or an account change proceeds.
Step up only where the money is
Each journey sets its own threshold. Reading a balance can clear at a lower score than adding a payee or changing an email address, so genuine customers rarely see a challenge and risky sessions always do.
When the score falls mid session, the step-up happens at the sensitive action rather than at the front door, which is where fraud actually lands.
Evidence for the fraud team
Every decision keeps the factors that produced it, so a disputed block or an approved transfer can be explained after the fact instead of reconstructed from logs.
The same engine covers AI agents acting for customers, so automated activity is authorised with scoped, revocable tokens rather than being mistaken for the human it acts on behalf of.