Microsoft on October 22 attributed the recent supply-chain compromise of ConnectWise's Cloud Backup service to Storm-0940, a China-state-aligned threat group it has tracked since 2021, disclosing that the actor deployed an agentic AI penetration-testing framework to automate attacks against hundreds of organizations globally2,5.
The framework, ARTEX, is a Go-based tool originally built for security testing that uses AI models to automate scanning, reconnaissance, password spraying, and OAuth application abuse. Microsoft said Storm-0940 used the tool at "machine speed" to accelerate compromised-application abuse, authenticating to target environments through applications that had already been granted access and operating without requiring an interactive user sign-in.
Scale of the campaign
Storm-0940 began the campaign as early as September 2026, targeting organizations across aerospace and defense, automotive, chemicals, energy, financial services, government, legal, manufacturing, media, military, semiconductors, software, technology, think tanks, and non-profits. Immediately before the ConnectWise compromise, the group ran a widespread but unsuccessful password-spraying campaign: over a four-day stretch ending October 14, it targeted 327 Microsoft 365 and Exchange Online accounts across eight organizations, generating more than 151,000 failed logon attempts and peaking at 2,900 failures per minute.
Storm-0940 pivoted to ConnectWise the next day, using AI agents and the same infrastructure to compromise a series of ConnectWise Cloud Backup customers' Microsoft 365 environments. Post-compromise activity included reconnaissance, application credential changes, and attempts to modify privileges to enable expanded or persistent access.
Scope of downstream targeting
The attackers attempted access to more than 2,250 Microsoft 365 tenants following the ConnectWise breach, abusing stolen application credentials and permissions already approved by customers rather than requiring users to enter passwords3. Earlier reporting had documented unauthorized sign-ins across 173 tenants; that confirmed-access figure differs from the broader targeting count, as not every attempted sign-in succeeded and successful authentication alone does not prove data theft.
Parallel research, open questions
Researchers from Zscaler and Microsoft teams separately documented ARTEX abuse in reports published October 21. Zscaler examined a Chinese-speaking operator's broader workflow without establishing that both investigations covered the same actor. ARTEX was previously made closed-source after its abuse against South Korean financial institutions.
Microsoft said the incident demonstrated how threat actors were using AI agents to automate existing attack methods and attempt to compromise multiple organizations at greater speed4. ANALYSIS The ConnectWise case marks a concrete, publicly attributed instance of a nation-state group operationalizing an agentic AI framework not to discover novel vulnerabilities but to compress the time between initial access and lateral movement across a supply-chain target's customer base.