The Ledger Donjon research division, led by expert Baptiste Boileau, has presented a detailed report on a vulnerability in Tangem hardware wallets. The issue involves a physical attack using laser fault injection, which allows resetting the card's password and gaining full control over the digital assets stored on it. This is a serious signal for the industry, especially considering that Tangem positions its devices as some of the most secure on the market.
Tangem hardware wallets are designed as plastic NFC cards resembling bank cards. Inside is a secure Samsung S3D232A chip with EAL6+ certification, which generates and stores private keys and signs transactions when connected to a mobile app. The standard security model is based on two factors: physical possession of the card and knowledge of the password. Additionally, there is a mechanism for restoring access if the password is lost, using a second backup card.
The researchers focused on the logic of the SetPin instruction, responsible for changing the password. The chip's firmware includes a check to determine whether the card is in a permitted state for recovery. Using a single nanosecond laser pulse directed at a specific area of the EAL6+ chip, Boileau managed to disrupt this check. As a result, the card accepted a new password without entering the old one and without needing the backup card.
To carry out the attack, it was necessary to open the card, expose the secure element, and connect it to a custom hardware platform. Then, using side-channel analysis, the researcher identified the exact moment the required check was executed and directed the laser pulse at the chip area associated with the instruction execution logic. After resetting the password, an attacker gains the ability to sign transactions and withdraw funds.
It is important to emphasize that the attack is physical and invasive. It cannot be carried out covertly, and the card cannot be restored to its original state without signs of tampering. According to Boileau, the only real risk is a lost or stolen card. If the device remains with the owner, this attack is not feasible. However, once the parameters for a specific model are found, each new exploitation attempt takes about two hours of preparation.
The cost of the necessary equipment, including a laser setup and tools for side-channel analysis, is estimated at approximately $250,000. In addition to financial costs, the attack requires deep knowledge in the field of hardware security. Tangem, for its part, called the risk for ordinary users "practically non-existent," emphasizing the need for physical access to the card and expensive laboratory equipment. The company also noted that Ledger is their direct competitor and urged consideration of this fact when evaluating the research results.
Boileau pointed out the limitations of EAL6+ certification: it confirms the secure element's resistance according to certain criteria but does not guarantee the absence of vulnerabilities in the firmware logic running on top of that chip. He 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. The problem is compounded by the fact that the vulnerability affects all Tangem cards in circulation and cannot be fixed with a patch due to the lack of firmware update support.
My professional comment: This research is another reminder that even the most advanced hardware solutions are not absolutely invulnerable. Physical attacks, although requiring significant resources, pose a real threat to high-value targets, such as large cryptocurrency holders or institutional investors. The market needs to move toward implementing multi-layered protection, including not only certified chips but also carefully designed software with redundant checks.