Ledger Donjon's research division has demonstrated a serious physical vulnerability in Tangem hardware wallets. The attack involves laser fault injection, allowing a password reset on the plastic NFC card and granting full control over the crypto assets stored on it. This is a critical defect that cannot be fixed with a software update, as the devices do not support firmware reflashing.
How the Vulnerability Works
At the core of the Tangem wallet is a Samsung S3D232A secure element with EAL6+ certification. This chip generates and stores private keys, and signs transactions when connected to a mobile app via NFC. Standard protection involves two factors: physical possession of the card and knowledge of the password. However, researcher Baptiste Bouatou discovered a flaw in the logic of the SetPin instruction used during password changes.
The firmware includes a check that only allows password reset if a backup card is present. Ledger Donjon managed to bypass this using a single nanosecond laser pulse directed at a specific area of the EAL6+ chip. To do this, the researcher opened the card, exposed the secure element, connected it to a custom hardware platform, and used side-channel analysis to determine the exact moment the required check was executed.
Practical Aspects of the Attack
After resetting the password, an attacker can sign transactions and withdraw funds. However, executing the attack requires significant resources: the equipment for the experiment costs around $250,000, and each new attempt after parameter setup takes about two hours. It is important to emphasize that the attack is physical and invasive — the card does not remain undamaged. Real risk only exists for lost or stolen devices.
Tangem's Response and Expert Analysis
Tangem stated that the risk for ordinary users is "practically non-existent," citing the need for expensive laboratory equipment and expertise. They also noted that Ledger Donjon, being a division of a direct competitor, may have a biased position. Nevertheless, Bouatou himself highlighted the limitations of EAL6+ certification: it confirms the chip's resilience according to certain criteria, but does not guarantee that the firmware logic running on top of it lacks vulnerable checks.
Among the expert's recommendations are implementing multiple independent checks for critical operations, more robust state encoding, and enhanced protection for password changes, even if the recovery function is disabled. In my view, this incident is another reminder that even certified hardware is not a panacea. Wallet security is determined not only by the chip but also by the quality of the firmware, which is often overlooked when choosing a device.