Analysis
Microsoft Threat Intelligence reports that Storm-0940, which it describes as a China-state aligned actor, used the agentic AI penetration testing framework ARTEX to target hundreds of organizations globally from as early as September 2026. Microsoft says that in multiple instances the time from initial targeting to privileged access was less than three hours. It also reports ARTEX-driven sign-in attempts against more than 2,250 tenants following unauthorized access associated with ConnectWise Cloud Backup. Microsoft separately observed a Storm-0940 password-spray campaign targeting 327 accounts across eight organizations, peaking at 2,900 failed logons per minute. Microsoft observed no successful authentication in that password-spray campaign.
Microsoft also assesses that Storm-0940 was responsible for the recently disclosed ConnectWise supply chain compromise of a multi-tenant application. After gaining control of identities for ConnectWise cloud applications, the agents used those applications to authenticate to customer environments without requiring an interactive user sign-in. Microsoft states that the activity did not result from a compromise of or a vulnerability in Microsoft corporate systems, products or services, and that an affected application, or even a successful authentication, does not necessarily mean data was accessed.
Analysis: the practical lesson is about tempo and inventory. When automated sign-in attempts run at thousands per minute, a response plan that depends on a periodic review of vendor access is too slow. Microsoft's guidance is specific: keep affected ConnectWise connections disabled until ConnectWise provides formal restoration instructions, do not delete enterprise applications as the first response, inventory the listed application IDs rather than searching by display name, and review activity from at least October 15, 2026 (Microsoft suggests extending service-principal sign-in review to October 1 where records allow). The underlying test for any organization is whether it can list every multi-tenant application with access to its tenant and say what each one is allowed to do.
Source: AI-driven, large-scale nation-state campaign using ARTEX enables supply chain compromise · 2026-10-21
Why it matters
Inventory third-party application access by ID and rehearse disabling it, because agent-driven attacks shorten the time available to notice misuse.