Hardware security experts have identified a serious vulnerability in the security system of popular Tangem cryptocurrency wallets. It has been established that through laser exposure, an attacker with physical access to the storage card can completely reset the password and gain control over all digital assets associated with it.
At first glance, Tangem wallets look like ordinary bank cards. Inside, they are equipped with a secure Samsung chip certified to EAL6+, responsible for generating and storing keys, as well as signing transactions. The master key never leaves the card, and access to funds is protected by two factors: physical possession of the card and knowledge of the password.
However, as detailed analysis showed, the "Achilles' heel" turned out to be the password recovery logic. Cards are sold in sets of two or three with a shared master key, and the standard mechanism allows password reset if two linked cards are available. It is in this function that the vulnerability lies.
The Essence of the Laser Attack
The recovery mechanism includes a conditional check: whether the card is in recovery mode. If yes, a new password is accepted without entering the old one. The goal of the attack is to "break" this single check, forcing the card to accept a new password without activating the "real" recovery mode.
The problem is compounded by the fact that the password change command has no protection against brute force. Unlike authentication commands, it does not introduce delays or lockouts after failed attempts, allowing repeated tries.
The attack itself is technically complex and invasive. Researchers opened the plastic card casing with a scalpel, removed the protective screen, exposed the silicon chip die, and resoldered the antenna for stable power. The primary method was laser fault injection. A powerful pulse of infrared light is aimed at a specific point on the die at a precise moment of operation, temporarily altering the state of transistors and disrupting the program flow—in this case, bypassing the required check.
A separate issue was the chip's own protection. Upon detecting tampering, the chip would write data to flash memory, and after approximately 256 such events, the cards would fail irrecoverably. To bypass this, the team learned to monitor writes in real-time and cut power before completion.
Scope of the Threat and Conclusions
It is important to emphasize that disabling the password recovery function in settings does not help. This setting only blocks one of the legitimate recovery commands, whereas the attack itself does not use it but directly targets the state check.
Meanwhile, the company notes a high barrier to execution: the attack requires physical access to the card, specialized laboratory equipment costing around $250,000, and deep expertise in hardware security. On a prepared model, it achieved 100% reproducibility, with each new attempt taking about two hours.
The key takeaway for users: there is no patch, but the danger is real. The attack cannot be carried out unnoticed, and the card cannot be returned untouched. Real risk only arises if the card is lost or stolen; if it remains with the owner, the described scenario is impossible.
Expert opinion: This finding is a vivid example that even certified "hardware" does not guarantee absolute protection. For the average user, Tangem remains a secure solution as long as the card never leaves their hands. However, investors with large sums should consider multi-factor protection and the use of open-source wallets, where vulnerabilities of this level are discovered and patched faster.