Researchers from Ledger Donjon, the security analysis division of Ledger, have identified a critical vulnerability in Tangem hardware wallets. As an independent analyst, I must note that this finding raises important questions about the boundaries of secure chip certification and the actual security of user devices.
The attack, based on a laser fault injection method, allows an attacker to reset the password on a Tangem card and gain full control over the crypto assets stored on it. The issue affects all Tangem cards currently in circulation and, critically, cannot be fixed with a software update, as the devices do not support firmware updates.
Technical Details of the Attack
At the core of the Tangem wallet is a Samsung S3D232A secure element with EAL6+ certification, which generates and stores private keys and signs transactions. Access to funds is typically protected by two factors: physical possession of the card and knowledge of the password. Tangem also implements a recovery mechanism that allows resetting the password if two linked cards are available.
Researchers from Ledger Donjon focused on the logic of the SetPin instruction used during password changes. They discovered that the firmware includes a check to determine whether the card is in an allowed state for recovery. Using a nanosecond-duration laser pulse directed at a specific area of the chip, they were able to disrupt this check and force the card to accept a new password without entering the old one and without needing a backup card.
To successfully execute the attack, the card must be opened to expose the secure element, connected to a specialized hardware platform, and the exact moment of the check execution must be determined using side-channel analysis. Once the parameters for a specific model are found, each subsequent attempt takes about two hours. However, as emphasized in the report, the attack is physical and invasive: it leaves traces and cannot be carried out unnoticed.
Practical Feasibility and Cost
It is worth noting that carrying out such an attack requires more than just a stolen or lost card. According to Ledger Donjon's estimates, the laboratory setup for the experiment costs around $250,000. Additionally, expensive laser equipment, tools for side-channel analysis, and significant expertise in hardware security are needed. Thus, while the vulnerability is serious, its exploitation in real-world conditions against ordinary users is unlikely.
Tangem, for its part, called the risk to ordinary users "practically non-existent," citing the high barrier to entry for an attacker. The company also noted that Ledger Donjon is a division of their direct competitor, which could influence the interpretation of the results. Nevertheless, the very existence of such an attack underscores that even EAL6+ certification is not a panacea, and the software logic on top of the secure element must be developed with specific threats in mind.
My expert conclusion: This vulnerability is not a reason for panic among Tangem owners, but it is an important reminder for the entire industry. Chip certification does not guarantee the security of the entire system as a whole. Manufacturers need to implement additional, independent checks for critical operations, such as password changes, and more robust state encoding. For users, the main lesson remains the same: the physical security of the device is your first and most important line of defense.