VERDICT —OUT OF SCOPE
Root cause is private-key / signer compromise — the on-chain contract behaved exactly as written. No pre-deployment source audit or bytecode review reaches the key-custody perimeter; this is operational-security territory (HSM/MPC hygiene, key rotation, hot-wallet isolation). Bytecode would show nothing wrong.
▰ METHOD
PRIVATE KEY
PRIVATE-KEY
Root cause
Root-cause analysis not yet published. The incident description below contains all currently available signal — review the attack transaction directly for definitive forensics.
Forensic narrative
According to monitoring by the SlowMist security team, cryptocurrency exchange BigONE has suffered a supply chain attack, with losses exceeding $27 million. The attacker breached the production network and altered the operating logic of servers related to account management and risk control, enabling unauthorized fund withdrawals. Notably, no private keys were leaked in this incident. Attack method (per SlowMist): Supply Chain Attack. Reported loss: $ 27,000,000.
Primary source
https://x.com/SlowMist_Team/status/1945346830222680330 ↗Sourced from
slowmist
Technical record
- chain
- —
- protocol
- BigONE
- bug_class
- private-key
- date_occurred
- 2025-07-16
- loss_usd
- $27,000,000
- source_id
- sm:bigone::2025-07-16
Related — same bug class· private-key