Briefing
A critical vulnerability has been disclosed in Tangem hardware wallet cards, enabling a physical side-channel attack to bypass PIN security. Ledger’s Donjon team demonstrated a “tearing attack” that allows an attacker to perform unlimited PIN attempts by interrupting power before a failed entry registers, coupled with electromagnetic analysis to identify the correct PIN. This flaw, which cannot be patched on existing cards, exposes assets stored on affected devices to potential direct theft.
Context
Hardware wallets are generally considered the gold standard for cold storage, designed to isolate private keys from online threats. The prevailing security posture relies on robust physical tamper-resistance and cryptographic safeguards, including limited PIN attempts to prevent brute-force attacks. This incident challenges the assumption of physical security in certain hardware wallet designs.
Analysis
The exploit targets the Tangem card’s internal logic, specifically how it handles failed PIN attempts. By interrupting the card’s power supply during a PIN verification cycle, the attacker prevents the device from registering the failed attempt, effectively granting infinite retries. Concurrently, side-channel analysis of electromagnetic emissions during PIN entry allows the attacker to distinguish between incorrect and correct digits, significantly accelerating the brute-force process. This chain of cause and effect circumvents the fundamental security mechanism of limited PIN attempts, making the wallet vulnerable to an attacker with physical access and specialized equipment.
Parameters
- Targeted Device → Tangem Hardware Wallet Cards
- Vulnerability Type → Physical Side-Channel / Brute-Force Attack
- Exploit Method → “Tearing Attack” (power interruption) combined with Electromagnetic Analysis
- Disclosing Entity → Ledger’s Donjon team
- Patch Status → Unpatchable on existing cards
- Impact → Potential for direct asset theft via PIN compromise
Outlook
Users of Tangem cards should assess their risk exposure, particularly if physical security of their devices cannot be guaranteed. This disclosure will likely prompt a re-evaluation of hardware wallet physical security and side-channel resistance standards across the industry, emphasizing the need for robust tamper-detection and more sophisticated PIN-attempt limiting mechanisms. New security best practices may emerge, advocating for multi-factor authentication or geographically distributed key shares even for cold storage.
Verdict
This hardware wallet vulnerability represents a critical breach in the assumed physical security of cold storage, demanding immediate user awareness and a fundamental re-assessment of device-level cryptographic protections.
Signal Acquired from → Protos
