Quantum Fault: Laser Attacks Can Bypass Access Code Locks on Tangem Hardware Cards
Executive Summary
Security researchers at Ledger Donjon have published a groundbreaking technical analysis demonstrating a highly advanced physical fault injection attack capable of bypassing access code locks on card-based Tangem cryptocurrency hardware wallets. By targeting the card's secure element chip with a single, nanosecond-duration laser pulse at a highly precise microscopic coordinate, researchers successfully forced the device's verification loop to fail. This physical disruption triggered an internal firmware fallback sequence that reset the user-defined access code to a null state, granting full access to the wallet's cryptographic private keys and associated digital assets without physically damaging the hardware.
Technical Analysis of the Fault Injection Attack
The Tangem hardware wallet is a card-based cryptocurrency storage solution that utilizes a certified, high-security secure element (EAL6+) chip. Unlike traditional hardware wallets with displays and physical buttons, Tangem cards authenticate transactions via Near Field Communication (NFC) using a companion smartphone application, relying on a user-defined alphanumeric access code to authorize key access.
The physical attack executed by Ledger Donjon relies on Laser Fault Injection (LFI):
Exploit Mechanics and Execution:
1. Motherboard Decapping: The researchers carefully removed the card's protective plastic outer layers to expose the raw silicon secure element chip.
2. Locating the Passcode Verification Loop: Under high-powered microscopes, researchers mapped out the physical layout of the chip, identifying the micro-routing lines and memory registries responsible for processing the access code verification loop.
3. The Laser Pulse: While sending a verification command to the card over the NFC interface, researchers directed a single, nanosecond-duration infrared laser pulse at a highly specific coordinate on the chip's surface.
4. State Disruption and Access Reset: The laser pulse injected a localized electromagnetic fault, temporarily scrambling the chip's logical state and forcing the conditional pass/fail logic of the passcode validation loop to evaluate as a "pass" or bypass. This fault reset the stored access code register to an empty state.
5. Master Seed Recovery: Once the access code lock was bypassed, researchers used automated script loops to query the secure element, retrieve the wallet's master cryptographic seed, and fully clone the card, gaining complete control of all associated on-chain digital assets.
Technical Parameter
Specification / Result
Target Device
Tangem Card Hardware Wallet
Exploit Mechanism
Laser Fault Injection (LFI) and Motherboard Silicon Probing
Impact
Total Alphanumeric Access Code Bypass, Wallet Cloning, and Private Key Theft
Prerequisite
Physical Possession of the Target Card and Specialist Lab Equipment
Threat Landscape and Physical Custody Defenses
The Tangem laser fault injection attack represents a high-sophistication, nation-state-level threat vector. LFI attacks require specialized, extremely expensive laboratory hardware (including optical microscopes, precise laser tables, and signal synchronization equipment), making it highly impractical for standard street-level criminals.
However, the attack shatters the absolute security guarantees of hardware-based self-custody. It demonstrates that physical possession of a secure element chip, when combined with specialist laboratory equipment, can bypass logical access codes and secure firmware barriers, completely compromising digital asset stores.
Recommendations and Mitigations
For cryptocurrency holders and organizations managing digital asset treasuries, the following mitigations are recommended to protect against physical device compromises:
1. Implement Multi-Signature (Multi-Sig) Protocols: Never rely on a single physical hardware wallet or card for large holdings. Distribute keys across multiple independent hardware wallets from different manufacturers, ensuring a physical compromise of one device cannot compromise the treasury.
2. Secure Physical Storage: Store hardware wallets in secure, fireproof safes, safety deposit boxes, or restricted-access vaults to prevent unauthorized physical possession and decapping attacks.
3. Use Alphanumeric Passphrases (BIP-39 Passphrase): Ensure your hardware wallets utilize an additional, user-defined BIP-39 passphrase (often called a "hidden wallet" or "25th word"). Unlike local access codes, passphrases are not stored on the physical device itself, rendering LFI attacks useless since the physical secure element cannot leak a key it does not contain.
4. Deploy Dual-Chip Hardware Verification: Hardware manufacturers should implement active physical shield sensors and light-detection grids on secure element surfaces, designed to automatically zero-out and wipe all cryptographic keys if physical decapping or localized light injection is detected.