Microsoft links ConnectWise supply-chain breach to AI attack tool

Microsoft said on 21 October 2026 that a China-state aligned threat actor it tracks as Storm-0940 used an agentic AI penetration testing framework called ARTEX to automate attacks against hundreds of organisations worldwide, and that it assesses the same actor was responsible for the recently disclosed ConnectWise supply-chain compromise of a multi-tenant application.

According to Microsoft Threat Intelligence, the activity began as early as September 2026 and hit a broad range of industries, including aerospace and defence, automotive, chemicals, energy, financial services, government, legal, manufacturing, media, military, semiconductors, software, technology, and think tanks and non-profits. Several of the ARTEX-driven attacks gave the actor privileged access to a victim's cloud infrastructure. In multiple cases, Microsoft said, the time from first targeting an organisation to obtaining that privileged access was under three hours.

ConnectWise publicly reported unauthorised access to its customers' tenants using multiple OAuth application identities on 16 October 2026. OAuth applications are software identities that customers have already granted access to their data. Microsoft said Storm-0940 used those already-trusted applications to authenticate into Microsoft 365 customer environments without needing an interactive user sign-in. In multiple affected environments, Microsoft observed follow-on activity through Microsoft Graph, the programming interface for Microsoft 365 data, including reconnaissance, changes to application credentials, and attempts to modify privileges in ways that could enable expanded or persistent access.

Microsoft stated that the activity did not result from a compromise of, or a vulnerability in, Microsoft corporate systems, products or services. It also cautioned that the presence of an affected application, or a successful authentication by the actor, does not by itself mean that customer data was accessed or taken.

ARTEX, as Microsoft describes it, is an open-source penetration testing framework that can run on any AI model. It is a multi-agent system built in Go with a Next.js web front end, and its interface and output can be switched between English, Korean, Mandarin, Spanish and Japanese. The framework's agents run an autonomous penetration test from reconnaissance through to data exfiltration with little human involvement, building a graph of discovered assets and vulnerabilities as they go. Microsoft said public reporting in October 2026 noted that ARTEX was being used by threat actors, including in personal data breaches targeting Korean financial institutions, and that it has identified actors in multiple geographic regions using the framework.

During the ConnectWise compromise, Microsoft said Storm-0940 used ARTEX to speed up scanning and reconnaissance, password spraying and OAuth application abuse at downstream victims. The company noted that such automated activity generates a large volume of traffic and log data that may trigger alerts, but that the speed leaves defenders very little time to act on those alerts and remove the attacker's access in a coordinated way. Most of the targeting was unsuccessful, Microsoft said, but the actor achieved privileged cloud persistence at many organisations in a short period.

Storm-0940 has been active since 2021 and targets organisations across multiple industries for data theft, according to Microsoft. It has historically gained initial access through password spraying and the exploitation of internet-facing applications, and has established persistence in cloud environments by adding credentials to existing OAuth applications.

Microsoft advised customers to review service principal sign-ins, investigate unexpected application credential or privilege changes, and follow ConnectWise's published containment guidance while preserving evidence. It said Microsoft Defender XDR provides detections and hunting queries for suspicious Microsoft Graph activity and for activity tied to known threat infrastructure.