Microsoft Says China-Aligned Storm-0940 Used the ARTEX AI Agent Framework to Run the ConnectWise Supply-Chain Attack

Microsoft's account of the ConnectWise breach is a detailed public case of a state-aligned group running an AI agent framework in a real intrusion, and its main lesson is about speed: Microsoft says the activity generated alerts but left defenders very little time to act on them. In a security blog post published on Wednesday, October 21, Microsoft Threat Intelligence said Storm-0940, which it describes as a China-state aligned actor, used the agentic penetration-testing framework ARTEX to automate attacks "targeting hundreds of organizations globally across a broad range of industries."

What Microsoft says happened

Microsoft says that as early as September 2026, Storm-0940 used ARTEX for scanning and reconnaissance, password spraying and abuse of OAuth applications. It lists targeted sectors including aerospace and defense, energy, financial services, government, semiconductors, software and think tanks.

Microsoft assesses that Storm-0940 was responsible for the compromise of ConnectWise's Cloud Backup service, which ConnectWise disclosed on October 16. After the unauthorized access, Microsoft says, "Storm-0940 used ARTEX to attempt to sign-in to more than 2,250 tenants." It says the attacker's AI agents then used the stolen app credentials to reach some customer environments.

In some environments, Microsoft says, the agents went on to make changes involving identities, groups and privileged roles. It says several of the group's attacks reached privileged cloud access, "including multiple instances where the time from initial targeting to privileged access was less than 3 hours."

The earlier password spray

Microsoft describes a separate, earlier campaign from October 10 to 14 that targeted 327 accounts across eight organizations. It says its telemetry recorded more than 151,000 failed logons, peaking on October 11 at 2,900 failures per minute. "Despite the scale, no successful authentication, token issuance, Graph call, or directory change was observed," Microsoft wrote. It links that campaign to the ConnectWise attack through shared infrastructure.

What Microsoft says about its own systems and customers

Microsoft says the activity "did not result from a compromise of or a vulnerability in Microsoft corporate systems, products, or services." It also says the presence of an affected application, or even a successful sign-in, "does not necessarily indicate that customer data was accessed or exfiltrated." Its advice to customers includes keeping affected ConnectWise app connections disabled until ConnectWise gives restoration instructions, and not deleting enterprise applications as a first step, so evidence is preserved.

CyberScoop reported that ConnectWise temporarily shut down services on Saturday after the attacks, began restoring them in phases on Wednesday, and expects recovery to take several days. It also quoted Microsoft executive vice president Igor Tsyganskiy: "Since early October, a wave of AI-driven cyberattacks has been ongoing."

What ARTEX is

Microsoft describes ARTEX as "an open-source penetration testing framework that can use any AI model to automate a variety of offensive security workflows," built as a multi-agent system that runs "from reconnaissance through data exfiltration with little needed human interaction." It says threat actors in several regions are using it. We covered ARTEX's earlier use against Korean financial institutions.

Limits

• This story is from October 21, outside our usual daily window; we are publishing it now because we had not covered it.
• The attribution is Microsoft's assessment. We have not seen a statement from ConnectWise naming Storm-0940, and Microsoft has not said how many customers were compromised.
• CyberScoop's article quotes Microsoft as saying Storm-0940 reached "more than 2,250 tenants at 2,900 sign-in attempts per minute." In Microsoft's blog, the 2,900-per-minute figure belongs to the earlier failed-logon password spray, not to the tenant sign-in attempts, so we keep the two numbers separate.
• Microsoft calls ARTEX open source. Our earlier coverage cited an AFP report that ARTEX's developer had taken it closed-source; we did not check its current status.
• We have left out the network indicators Microsoft published.

Sources

• Microsoft Security Blog: AI-driven, large-scale nation-state campaign using ARTEX enables supply chain compromise (October 21, 2026)
• CyberScoop: Microsoft pins ConnectWise supply-chain attack to China-state aligned threat group (October 21, 2026)
• Times of AI: CrowdStrike says the Korean bank attacker drove ARTEX through Claude Code (October 2026)