Tangem hardware wallets, designed in the form of NFC cards, have proven vulnerable to physical attacks. Baptiste Bouillot, a researcher from the Ledger Donjon division, demonstrated a laser fault injection method that allows resetting the password on the device and gaining full access to stored assets.
The problem lies in the architecture of the cards themselves. Inside, a secure Samsung S3D232A chip is used, certified to the EAL6+ standard. However, as analysis showed, the firmware logic responsible for verifying the state during a password change (the SetPin instruction) can be bypassed. Normally, resetting a password requires either knowledge of the old one or possession of a second backup card. But a nanosecond-duration laser pulse directed at a specific area of the chip disrupts this verification and forces the device to accept a new password without any confirmation.
Technical Details of the Attack
The attack process requires serious preparation. First, the researcher opens the card, exposing the chip. Then, using side-channel analysis, the exact moment of the vulnerable check's execution is determined. Once the parameters for a specific chip model are found, each subsequent hacking attempt takes about two hours. A successful password reset immediately gives the attacker the ability to sign transactions and withdraw funds.
The key point is that this is a physical and invasive attack. It cannot be carried out remotely or covertly, and the card remains damaged after the intervention. As Bouillot himself notes, the only realistic risk scenario is a lost or stolen card. If the device is in your possession, this attack is not feasible.
The cost of the necessary equipment is estimated at around $250,000. This includes a laser setup, tools for side-channel analysis, and, importantly, deep knowledge in the field of hardware security.
Tangem's Response and Practical Conclusions
Tangem representatives, in turn, called the risk for ordinary users "practically non-existent," emphasizing that the scenario requires physical access to the card and expensive laboratory equipment. They also pointed out that Ledger Donjon is a research division of their direct competitor and urged considering this context when evaluating the findings. The company reasonably noted that with sufficient resources, the firmware of any secure element can be studied and potentially exploited.
However, Bouillot highlights the limitations of even EAL6+ certification. It confirms the chip's resistance to certain hardware attacks but does not guarantee that the software logic running on top of it is free of vulnerabilities. The expert's recommendations include implementing multiple independent checks for critical operations, more robust state encoding, and strengthening the password change procedure, even if the recovery function is disabled.
My professional opinion: This case is a classic example of how hardware certification is not a panacea if the software running on it is flawed. For the average user, the threat is minimal, as it requires physical access to the device and significant resources. However, for owners of large sums who could become targeted victims, this is a serious signal about the need to diversify asset storage and use wallets with firmware update capabilities.