Blockchain analytics firm Chainalysis has confirmed that hackers stole login credentials and live session tokens belonging to all of its users, in a breach the company described as a "multifront cyberattack" that began in October 2026.
Chainalysis first disclosed the incident on October 30, saying at the time that only non-sensitive customer data — such as user IDs, full names, email addresses, and organization role labels — had been accessed, and that authentication credentials and session tokens appeared untouched. The picture changed this week. According to the company, an investigation on Monday, November 2, found that names, usernames, password hashes, and live session tokens for all Chainalysis users had been exposed to a malicious actor.
A further update on Wednesday, November 4, revealed that part of the attack involved an "on-path attack" that exposed a subset of customer passwords. Chainalysis said the attack vector had been identified and fixed. The company took its login portal, Reactor investigations tool, Data Solutions platform, and Know Your Transaction (KYT) service offline while it investigated, and said on Friday that access to KYT and Address Screening was being phased back in.
The breach is significant because of who uses Chainalysis. The firm's customers include government agencies such as the FBI, U.S. Immigration and Customs Enforcement, and the U.S. Air Force, as well as private companies including Microsoft, Coinbase, and Barclays, according to the company and public records cited by Ars Technica. All users have been told to reset passwords and rotate API keys before returning to the platform.
Chainalysis said it has found no evidence that investigation data was accessed or that its attribution data — the labels linking wallet addresses to real-world entities — was manipulated. The attacker has not been identified, and the company said the incident has no link to the $6.3 billion Binance theft that the FBI attributed to North Korea.
Crypto markets showed little immediate reaction. Bitcoin traded near $75,888 on Binance spot, up 0.35% over 24 hours, while Ether traded near $2,244, up 0.94%, as of November 7 at 15:21 UTC. The episode is a reminder that even the firms policing crypto crime can become targets — and that stolen session tokens, which can allow access without a password, deserve the same urgency as stolen funds.
This article is for informational purposes only and is not financial advice. Do your own research.
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