The Ledger Donjon research department, specializing in hardware security, has presented a detailed analysis of a physical vulnerability in Tangem hardware wallets. The attack, based on laser fault injection, allows an attacker to reset the password on the device and gain full control over the crypto assets stored on the card. This concerns plastic NFC cards that externally resemble bank cards but contain a secure chip for storing private keys.
The key issue is that the vulnerability cannot be patched: the firmware of Tangem cards is not updated. This means that all released models are at risk if the device falls into the wrong hands. However, the attack is purely physical and invasive, making it extremely difficult to apply covertly.
How the Attack Works
The wallet is based on the Samsung S3D232A secure element with EAL6+ certification. Typically, access to funds is protected by two factors: physical possession of the card and a password. There is also a recovery mechanism using two linked cards. Researchers from Ledger Donjon focused on the SetPin instruction, responsible for changing the password. They found that the firmware includes a check that allows password changes only under certain conditions (e.g., when a backup card is present).
Using a single nanosecond laser pulse directed at a specific area of the EAL6+ chip, the experts were able to disrupt the logic of this check. This allowed them to force the card to accept a new password without entering the old one and without using a backup card. By opening the card and connecting to the secure element via their own hardware platform, the researchers used side-channel analysis to determine the exact moment the vulnerable check was executed.
After resetting the password, the attacker gains the ability to sign transactions and withdraw funds. Preparation for the attack takes about two hours, but only if the parameters for that specific model are already known. The cost of equipment for such an attack is estimated at approximately $250,000, making it accessible only to well-funded groups or state actors.
Tangem's Response and Expert Conclusions
Tangem called the risk to ordinary users "practically non-existent," emphasizing that the scenario requires physical access to the card, expensive laboratory equipment, and deep expertise. Tangem also noted that Ledger Donjon is a division of their direct competitor, which may influence the interpretation of the results.
Nevertheless, researcher Baptiste Boileau highlighted the limitations of the EAL6+ certification itself. It confirms the chip's resistance to certain attacks but does not guarantee the absence of vulnerabilities in the firmware logic running on top of that chip. "The software running on these chips must be developed with special protection patterns in mind," he stated.
As recommendations, the expert proposed implementing multiple independent checks for critical operations, more robust state encoding, and strengthening the protection of the password change procedure, even if the recovery function is disabled.
My professional opinion: This case is a clear reminder that even certified "hardware" is not an absolute guarantee of security. A vulnerability in the firmware logic running on top of a secure element can negate all hardware advantages. For the average user, the risk is minimal, but for holders of large sums or institutional investors, this is a serious signal: security is not only about choosing a chip but also about the quality of the code executed on it. The market needs standards that cover not only the physical level but also the software logic.