Microsoft says a China-aligned group used the ARTEX AI agent to breach ConnectWise and hundreds more
A China-aligned group pointed an open-source AI agent framework at a backup vendor's app and tried 2,250 Microsoft 365 tenants at machine speed.
On October 21, 2026, Microsoft said a hacking group it ties to the Chinese state used an AI agent framework called ARTEX to attack hundreds of organizations. Microsoft Threat Intelligence, which tracks the group as Storm-0940, also named it as the attacker behind this month's break-in at ConnectWise's Cloud Backup service.
The campaign goes back as early as September 2026. In several cases, Microsoft says, the group went from first targeting an organization to holding privileged access in its cloud in under three hours.
- Group
- Storm-0940, a China-state aligned actor active since 2021
- Tool
- ARTEX, an open-source penetration testing framework
- Tenants targeted
- more than 2,250
- Pace
- 2,900 sign-in attempts per minute
- Fastest
- initial targeting to privileged access in less than 3 hours
What ARTEX is
ARTEX is open-source software that hands a penetration test to a team of AI agents. According to Microsoft it can run on any AI model, and its agents work from reconnaissance through to taking data out, with little need for a person to step in. It's written in Go, and its interface switches between English, Korean, Mandarin, Spanish and Japanese.
Security teams build tools like this to test their own defenses. Storm-0940 pointed it at other people's. Microsoft says it has seen threat actors in several regions using ARTEX, and its post points back to the October breaches at Korean financial institutions that public reporting tied to the same framework (our story).
How the ConnectWise break-in ran
Microsoft sets out the order of events. Between October 10 and 14, a server at one address ran a password-spray campaign against 327 accounts across eight organizations. Microsoft logged more than 151,000 failed logins, peaking on October 11 at 2,900 failures a minute. None got through.
On October 15, reports of a compromise at ConnectWise's Cloud Backup started to surface, with indicators from the same block of addresses, and ConnectWise posted its own advisory on October 16. Cloud Backup (formerly SkyKick) is an app that customers had already granted access to their Microsoft 365 accounts. Whoever holds its credentials can sign in without a user ever typing a password.
That's the access the agents went to work with. Microsoft says ARTEX tried to sign in to more than 2,250 tenants at 2,900 attempts a minute. Where it got in, the agents looked around, changed app credentials and made changes to identities, groups and privileged roles. One of the alerts Microsoft lists is for an app that gave itself the Global Administrator role.
they can work around the clock, on weekends, and on holidays and attempt multiple breach paths simultaneously
Most of the targeting failed, by Microsoft's account. Storm-0940 still got privileged, lasting access at many organizations in a short time, and the credentials its agents added can keep working as a backdoor after the original app is cleaned up. The alerts fire, Microsoft says, but at that speed defenders have very little time to act on them.
Microsoft says the attack didn't come through a flaw in its own systems or products. It also says an affected app, or even a successful sign-in, doesn't on its own show that anyone's data was read or taken.
the time from initial targeting to privileged access was less than 3 hours
What it means for businesses that hand their IT to someone else
ConnectWise's advisory is written for its partners, the firms that look after Microsoft 365 for their own customers. It asks them to review their own tenant and each managed customer tenant, so one compromised vendor app turns into a check of every customer account those partners look after.
ConnectWise says a China state-aligned group used an openly available agentic AI framework, and that it reached that view partly from threat intelligence Microsoft shared. It suspended Cloud Backup and, because they're built on it, SaaS Security and Cloud Management too. Backup jobs, archive access and restores are all unavailable, and the shutdown covered every user, whether or not the attackers reached their tenant.
The stored backups look intact. ConnectWise says the archives are encrypted and isolated, with no indication of compromise, but adds that this doesn't settle whether individual live Microsoft 365 environments were affected. I'd put that line next to Microsoft's three hours: the backups held, and the question for each business is what the agents did inside its live account.
Microsoft's first advice is to leave the ConnectWise connections switched off until ConnectWise sends formal restoration instructions, and not to delete the apps as a first response, since they're evidence. It asks admins to review activity from at least October 15, and back to October 1 where records allow. ConnectWise says restoration will come in stages and take several days, with each step subject to security review.