Experts from Ledger's research division, the Donjon team, have discovered a critical vulnerability in Tangem hardware wallets. This involves a laser fault injection attack that allows an attacker to reset the password on a physically captured card and gain full control over the assets.
Tangem wallets are plastic NFC cards that resemble bank cards externally. Inside, they feature a secure Samsung S3D232A chip with EAL6+ certification. This component is responsible for generating and storing private keys, as well as signing transactions when connected to a mobile app. The problem is that the vulnerability affects all issued cards and cannot be fixed — the devices do not support firmware updates.
Technical Details of the Attack
Ledger Donjon researcher Baptiste Boileau thoroughly analyzed the logic of the SetPin instruction used when changing the password. The firmware includes a check to determine whether the card allows access recovery. A nanosecond-duration laser pulse directed at a specific area of the chip can disrupt this check, forcing the card to accept a new password without entering the old one and without a backup.
The process requires serious preparation: first, the researcher opened the card, exposing the secure element, connected it to a custom hardware platform, and used side-channel analysis to identify the exact moment of the critical check. Then, the laser pulse was directed at the chip area associated with the instruction execution logic.
Once the parameters for a specific model are found, each subsequent attempt takes about two hours. After resetting the password, the attacker can sign transactions and withdraw funds.
However, the cost of equipment for such an attack is estimated at approximately $250,000. In addition to the laser setup, tools for side-channel analysis, deep knowledge of hardware security, and preparation time are required.
Tangem's Response and Context
Tangem stated that the risk for ordinary users is "virtually non-existent," as the scenario requires physical access to the card, expensive laboratory equipment, and expertise. The company also noted that Ledger Donjon, while positioning itself as an independent research unit, operates within one of Tangem's largest competitors. According to them, with sufficient resources, the firmware of any secure element can be studied and potentially exploited.
Boileau, in turn, highlighted the limitations of EAL6+ certification. It confirms the chip's resistance according to certain criteria but does not guarantee that the firmware logic on top of the chip lacks vulnerable checks. The expert recommended implementing multiple independent checks for critical operations, more robust state encoding, and additional protection for password changes, even if the recovery function is disabled.
My expert assessment: This research is an important signal for the entire hardware wallet industry. It clearly demonstrates that even top-level certification does not guarantee absolute security if the software logic on top of the chip contains flaws. For Tangem owners, the practical risk is minimal, but the very existence of such an attack vector underscores the need for more thorough firmware audits and the implementation of protective mechanisms at the application level. The competitive rivalry between Ledger and Tangem here only adds intensity to the discussion but does not negate the technical validity of the findings.