ZKsync

Private Key Leakage

Estimated loss

$5.00M

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.

Forensic narrative

The ZKsync security team discovered that an admin account had been compromised, giving the hacker control of approximately $5 million worth of ZK tokens — the remaining unclaimed tokens from the ZKsync airdrop. The ZKsync Security Council sent an onchain message to the hacker on Monday, April 21st at 15:03 UTC. In an effort to resolve this matter in the spirit of safe harbor, they offered a 10% bounty for returning 90% of the funds involved in the exploit. On Wednesday, April 23rd at 14:39 UTC, 90% of the funds were returned to the Era and Ethereum L1 addresses controlled by the Security Council. Attack method (per SlowMist): Private Key Leakage. Reported loss: $ 5,000,000.

Primary source

https://zksync.mirror.xyz/W5vPDZqEqf2NuwQ5x7SyFnIxqqpE1szAFD69iaaBFnI ↗

Sourced from

slowmist

Technical record