Chainalysis Breach Exposes All Users' Credentials, Forces Shutdown of Key Services

Blockchain analysis firm Chainalysis said an ongoing investigation into an agentic cyber attack targeting its systems exposed names, usernames, password hashes and live tokens for all users. The company removed access to Reactor and Data Solutions while it investigated, and said it has no evidence that investigations data was accessed or attribution data was manipulated. It also took the KYT user interface and API, other address screening products, and its login page offline.

Account Lockdown and Recovery Steps

Chainalysis locked impacted accounts out of caution. Customers who received reset emails cannot reset passwords right now, but the company encouraged resetting passwords on other systems where credentials may be reused. It plans to restore access to KYT and Address Screening, asking customers to send trusted IP addresses to support or their account team for an allowlist. After that, users can reset passwords and rotate API keys to register transactions. Chainalysis said it is working to harden systems and bring Reactor and Data Solutions back online, and every user will have to reset passwords and rotate API keys as appropriate.

Broader AI-Linked Attacks

The development comes less than a week after Chainalysis disclosed a cybersecurity incident in which an external actor used offensive agentic techniques to access its systems and internal tools. Chainalysis said the attack was similar to incidents affecting many other tech platforms in recent weeks. Companies including Chainstack, OpenCode, Warp, and WorkOS have disclosed AI-driven attacks, some involving an autonomous penetration testing tool called ARTEX.

Microsoft and Cloud Credential Abuse

Microsoft said threat actors use an agentic AI offensive framework to search public GitHub repositories for exposed secrets across applications and cloud services. In at least one case, an AI agent moved from scanning GitHub for secrets to exfiltrating data from Azure Key Vault in five minutes. The activity is assessed to be ongoing from August 2026, with sign-in events from two IP addresses, 199.19.77.84 and 199.19.77.18. The agent conducted service principal sign-ins across dozens of applications, targeted credential-returning operations, and compromised applications accessed SharePoint and OneDrive. Agents also obtained tokens for single-tenant OAuth applications, enumerated cloud resources, and in some cases exfiltrated secrets from Azure Key Vault, with a focus on credentials for AI services.

LLM Access Resale

Google disclosed that cybercriminals have built a business model around stealing cloud access to commercial large language models and reselling it. LLM Mixers act as illicit intermediaries that advertise access to compromised enterprise LLM accounts on underground markets. Google-owned Wiz identified at least two resale operations using stolen AWS Bedrock keys from two organizations. Separately, Zeabur disclosed a breach in which an unknown actor exploited plaintext credentials, exfiltrating over 3.2 million environment variable records and data tied to 321,810 accounts. Wiz said threat actors also compromise environments to abuse finances for mass LLM execution, incurring hundreds of thousands of dollars in AI API charges.

Earlier coverage: Chainalysis Confirms Intrusion Into Internal Tools and Exposure of Customer Identity Data

Sources: The Hacker News · Cybernews