Ledger Donjon's research division has identified a critical vulnerability in Tangem hardware wallets. The attack, based on laser fault injection, allows an attacker to reset the card's password and gain full control over the assets stored on it. This poses a serious challenge for an industry where the security of hardware wallets is considered the gold standard.
As a reminder, Tangem produces crypto wallets in the form of NFC cards resembling bank cards. Inside is a secure Samsung S3D232A chip with EAL6+ certification, which generates and stores private keys, as well as signs transactions when connected to a mobile app. The vulnerability affects all Tangem cards currently in circulation and, critically, cannot be fixed — the devices do not support firmware updates.
How the attack works
In a standard scenario, access to funds is protected by two factors: physical possession of the card and knowledge of the password. Tangem also has a recovery mechanism that allows resetting the password if two linked cards are available. Ledger Donjon researcher Baptiste Boileau focused on the logic of the SetPin instruction used when changing the password. He discovered that the firmware includes a check to determine whether the card is in an allowed recovery state.
Using a single nanosecond laser pulse directed at a specific area of the EAL6+ chip, the researcher was able to disrupt this check and force the card to accept a new password without entering the old one and without a backup card. This required opening the card, exposing the secure element, connecting it to a custom hardware platform, and using side-channel analysis to precisely determine the moment the required check was executed. After configuring the parameters for a specific model, each new attempt takes about two hours.
It is important to emphasize that the attack is physical and invasive — it cannot be carried out covertly, nor can the card be returned to an undamaged state. As Boileau noted, "the only real risk is a lost or stolen card; if it remains with you, the described attack cannot be performed." Additionally, the cost of equipment for such an attack is estimated at approximately $250,000, and deep knowledge in hardware security is also required.
Tangem's response and expert analysis
Tangem called the risk to ordinary users "practically non-existent," emphasizing that the scenario requires physical access to the card, expensive laboratory equipment, and high expertise. The company also noted that Ledger Donjon is a division of their direct competitor and urged consideration of this when evaluating the findings.
However, despite the high cost and complexity of the attack, its very existence raises important questions. Boileau rightly pointed out the limitations of EAL6+ certification: it confirms the secure element's resistance according to certain criteria but does not guarantee that the firmware logic running on top of the chip does not contain vulnerable checks. "The software running on these chips must be developed with special protection patterns in mind," he stated.
This incident is yet another reminder that hardware security is not absolute. Even certified chips can be compromised if the firmware does not meet high standards. The expert's recommendations — multiple independent checks for critical operations, more robust state encoding, and additional protection for password changes — should become industry standards.
My comment: Although the attack on Tangem is unlikely to pose a real threat to the average user, it demonstrates that the arms race in hardware wallet security continues. Manufacturers must not only rely on chip certification but also carefully design firmware logic, considering all possible attack vectors. For users, the main takeaway remains the same: the physical security of the device is your first line of defense.