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ATM Transaction Reversal Frauds: Cashing Out Without Malware

Hector Cuevas Cruz

Hector Cuevas Cruz explains Transaction Reversal Frauds (TRF), an attack that abuses banking operational rules to cash out ATMs without malware or drilling.

Summary

The Mechanics of Transaction Reversal Fraud (TRF)

Transaction Reversal Fraud (TRF) is a sophisticated physical-logical attack where criminals exploit business logic error-handling rules in ATMs to steal cash with zero net balance deduction.

Abusing Dispenser Error Handling and Sensor Timing

Hector Cuevas Cruz explains how manipulating the shutter during note presentation triggers an intentional timeout, tricking the ATM into reporting an uncollected cash fault.

Automated Account Reversals and Cash Theft

Because the host bank automatically reverses the debit transaction when an uncollected fault is logged, the attacker retains the physical cash while restoring their account balance.

Hardening ATM Shutter Timing and Host Reconciliation

The author provides banking institutions with dispenser sensor telemetry rules, dual-audit logging, and backend reconciliation controls to mitigate TRF attacks.

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