2,250 Tenants Targeted In AI-Led Attack On ConnectWise Chain

Attackers aligned with the Chinese state deployed an autonomous artificial intelligence agent to execute a massive supply chain assault against ConnectWise, reaching for sign-ins at more than 2,250 Microsoft 365 tenants. The operation, attributed to the actor known as Storm-0940, utilized ARTEX, an open-source framework designed to run an autonomous penetration test. The tool leverages a system of LLM-driven agents capable of scanning, reconnaissance, password spraying, and OAuth application abuse with minimal human interaction, a capability Microsoft says leaves defenders with little time to detect and respond.

The activity unfolded rapidly. On October 11, automated password guessing targeted 327 accounts across eight organizations, generating over 151,000 failed logons with no successes recorded. At the peak of that day, the attempt rate hit 2,900 per minute, totaling over 111,000 tries, with 48 accounts logging more than 1,000 failures each. While nearly 98% of that activity was locked out, the assault shifted to using stolen application credentials. With control of identities for multiple ConnectWise cloud apps, the attacking AI agents signed into customer tenants from the same IP range. More than 200 sign-ins occurred in under four minutes using four application credentials.

Operations within compromised tenants included Graph and directory operations, reconnaissance, app credential changes, and modifications to identities, groups, and privileged roles. In one tenant on October 15, the security firm Huntress observed an application adding itself to the top administrator role, a behavior that triggered the Microsoft Defender alert titled 'Application self-assigned Global Administrator role.' Actions involved planting new secrets scheduled to expire in 2028. Huntress confirmed unauthorized sign-ins for 162 tenants by October 16, expanding to nearly 1,000 Entra tenants with sign-in activity from the attacking IP by the next day, with more than 300 succeeding. The sequence of attacks through tenants in sorted order, a few seconds apart, indicated a script working from a target list.

Storm-0940, active since 2021, is described as a 'China-state aligned actor' with no known industry aliases. The campaign targeted 14 industries in total, including aerospace and defense, semiconductor, government, and think tanks. Microsoft stated the activity did not result from a compromise of or a vulnerability in Microsoft systems, products, or services. In some attacks reaching privileged access in less than three hours, the group attempted sign-ins at Microsoft 365 tenants using stolen ConnectWise app credentials.

ConnectWise suspended Cloud Backup, SaaS Security, and Cloud Management as a precaution and has started a phased restoration, with recovery expected to take several days. The company noted no indicators to date that partner backup data was compromised. Microsoft advises customers to keep affected app connections disabled until formal restoration instructions are issued. The source article date is 2026-10-23.

The use of the open-source penetration testing framework marks a shift from traditional attacks. Threat actors in multiple regions are utilizing the technology, and public reporting this month tied it to breaches at South Korean financial institutions. CrowdStrike said the suspect in those separate attacks was likely based in China and allegedly used ARTEX with Anthropic’s Claude Code. ARTEX’s developer, who goes by the handle ‘Autumn-27,’ stated on GitHub that the ARTEX project will no longer be updated and would become closed source.