Harmony

Private Key Leakage

Estimated loss

$100.00M

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.

▰ PROOF OF CONCEPT

DEFIHACKLABS

src/test/2022-06/Harmony_multisig_exp.sol

view forked test on github ↗

Reproducible Foundry test fork from SunWeb3Sec/DeFiHackLabs. Clone the repo, run forge test against the file path above, and replay the exploit against a mainnet fork at the historical block. Use for reproduction only — not for live targets.

Forensic narrative

Harmony Horizon bridge was hacked. According to the analysis of SlowMist MistTrack, the attackers made more than 100 million US dollars, including 11 ERC20 tokens, 13,100 ETH, 5,000 BNB and 640,000 BUSD. On the 26th, Harmony founder Stephen Tse said on Twitter that Horizon was attacked not because of a smart contract vulnerability, but because of a private key leak. Although Harmony stored the private keys encrypted, the attacker decrypted some of them and signed some unauthorized transactions. At present, Harmony has migrated Horizon's verification authority on the Ethereum side to 4/5 multi-signature. It is reported that this incident is suspected to be related to the North Korean hacker group Lazarus Group. Attack method (per SlowMist): Private Key Leakage. Reported loss: $ 100,000,000.

Primary source

https://twitter.com/harmonyprotocol/status/1540110924400324608 ↗

Sourced from

slowmist

Technical record