Chainalysis said hackers obtained password hashes and valid authentication tokens for all users, prompting it to take KYT transaction monitoring, address screening, the Reactor investigation platform, Data Solutions and Chain (Beta) offline. According to Odaily, the company plans to restore KYT and address screening services from November 5 using a trusted IP address allowlist. Chainalysis said it contained and fixed a “man-in-the-middle” attack targeting some customers’ passwords; affected accounts will remain locked until their passwords are changed. The company said it has found no evidence that confidential investigative data was accessed or blockchain attribution data was altered. It is requiring users to reset passwords and, where applicable, rotate API keys, and has hired external cybersecurity experts and used large language models to examine its systems and strengthen defenses.