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The Dirty Laundry of Stored Value Washing Cards

Aidan NakacheEquip

Details reverse engineering stored-value contactless laundry cards, uncovering data structure vulnerabilities that allow arbitrary balance modification.

Summary

The Ubiquity of Stored-Value Contactless Cards

Commercial laundry facilities and municipal services worldwide rely on offline stored-value contactless smartcards to process payments without real-time backend network connectivity.

Reverse Engineering RFID Memory Layouts

Aidan Nakache and Equip analyze the internal memory structures, sector keys, and cryptographic checksum algorithms of popular commercial laundry smartcards.

Discovering Balance Modification Flaws

Analyzing memory dumps before and after transactions revealed predictable counter fields and flawed integrity verification, allowing arbitrary balance manipulation.

Global Implications for Offline Payment Systems

The vulnerabilities identified in laundry cards reflect systemic architectural weaknesses across legacy offline stored-value and transit payment systems globally.

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