Chainalysis Says Hack Exposed Data Tied to Its Entire User Base

Chainalysis said information tied to all its users was exposed to a malicious actor; the company also took KYT, other address-screening products and its login page offline Nov. 4 after detecting abnormal activity.

The company said it discovered the exposure Nov. 2. The listed categories included names, usernames, password hashes and live tokens. Chainalysis has not defined the latter term or explained how it hashed passwords.

In a customer notice earlier Nov. 4, Chainalysis said an on-path attack exposed a subset of passwords. The company said it contained the attack, locked affected accounts and found no evidence those accounts were improperly accessed.

Phased restoration of KYT and Address Screening began Nov. 6. Customers must provide trusted IP addresses for an allowlist, reset passwords and rotate API keys where applicable. Chainalysis said it was still working to restore Reactor and Data Solutions.

KYT assesses risk in incoming and outgoing crypto transfers. The company said it had found no evidence that investigation data was accessed or attribution data altered.