Tangem hardware wallets, designed as plastic NFC cards, have long been considered a benchmark of security thanks to their certified EAL6+ chip. However, recent research has uncovered a critical vulnerability: laser fault injection allows an attacker to reset the card's password and gain full control over stored assets. This is a physical attack that cannot be fixed remotely, as the device firmware is not updated.
Inside each Tangem card is a secure element Samsung S3D232A, responsible for key generation and transaction signing. Access to funds is traditionally protected by two factors: physical possession of the card and knowledge of the password. In case of password loss, a recovery mechanism using a second linked card is provided. Researchers focused on the logic of the SetPin instruction, which checks whether the card is in an allowed state for password reset.
Technical Details of the Attack
Using a single nanosecond laser pulse directed at a specific area of the chip, it was possible to disrupt the recovery state check. After this, the card accepts a new password without requiring the old one or a backup card. To prepare the attack, it was necessary to open the casing, expose the secure element, connect it to a custom hardware platform, and use side-channel analysis to determine the exact moment the vulnerable check is executed.
Once the parameters for a specific model are found, each subsequent attempt takes about two hours. However, the cost of laboratory equipment is estimated at around $250,000, plus deep knowledge in hardware security is required. This makes the attack practically unfeasible for ordinary attackers, but it poses a serious threat in case of card theft or loss.
Tangem's Response and Conclusions
Tangem called the risk for ordinary users "practically non-existent," noting that the attack requires expensive equipment and physical access to the device. The company also pointed out that Ledger's research division is part of their direct competitor, which may influence the interpretation of results. Nevertheless, experts emphasize that EAL6+ certification confirms the chip's resilience according to certain criteria but does not guarantee protection of the firmware logic running on top of it.
Recommendations include implementing multiple independent checks for critical operations and strengthening password change protection even when the recovery function is disabled. This situation once again reminds us: no hardware wallet is absolutely invulnerable, and the security of crypto assets largely depends on physical control over the device.
Expert opinion from Cryptalist: This case is a vivid example of how hardware certification can create a false sense of security. The software logic running on the secure chip remains the weak link. Tangem users should pay closer attention to the physical safety of their cards, especially given that fixing this vulnerability without replacing the device is impossible.