COLDCARD RNG Integration Error Enables $88 Million Bitcoin Theft from Hardware Wallets
What Happened — Researchers uncovered an integration error in COLDCARD hardware‑wallet firmware that caused the device to fall back to a deterministic software RNG instead of the built‑in STM32 hardware RNG. The flaw let attackers reconstruct wallet seeds offline and sweep an estimated $88.6 million in Bitcoin from more than 4,500 addresses.
Why It Matters for Compliance & Audit Readiness
- Demonstrates the risk of weak cryptographic implementations—SOC 2 CC6.2 (Cryptographic Key Management) requires that key‑generation processes be demonstrably random and protected.
- Highlights the need for continuous control monitoring; evidence of firmware integrity checks and secure‑development lifecycle (SDLC) checkpoints is essential audit evidence.
- Shows that a single control gap can cascade into massive asset loss, underscoring the importance of mapping technical controls to SOC 2 criteria and maintaining a defensible audit trail.
Who Is Affected — Digital‑asset custodians, cryptocurrency wallet providers, and any organization that relies on hardware‑based key generation for financial transactions.
Recommended Actions
- Perform an immediate firmware integrity audit and verify that the hardware RNG is correctly invoked.
- Deploy the vendor‑provided patched firmware, document the change‑control process, and retain signed hashes as evidence.
- Map the RNG and key‑management controls to SOC 2 CC6.2, and set up continuous monitoring to capture firmware version, checksum, and RNG test results for audit readiness.
Technical Notes — The flaw stems from an incorrect check in the firmware that routes ngu.random to MicroPython’s deterministic Yasmarang fallback rather than the STM32 hardware RNG. The fallback uses the microcontroller ID and system timing—values that are observable and not cryptographically secure. No CVE has been assigned yet. Source: BleepingComputer