AI Agents Accelerate Massive Supply Chain Breach Across Microsoft Tenants

The landscape of corporate cybersecurity has shifted dramatically as automated systems take center stage in high-stakes breaches. A new report from Microsoft details how a China-state-aligned group known as Storm-0940 utilized an open-source artificial intelligence framework to execute a widespread supply chain attack.

The operation centered on unauthorized access to ConnectWise, a multi-tenant application that serves as a gateway to numerous customer environments. By exploiting stolen application credentials, the attackers bypassed traditional interactive sign-in methods. These credentials allowed the AI agents to authenticate directly as the applications, granting them seamless access to more than 2,250 distinct Microsoft 365 tenants.

The speed of the intrusion marks a significant departure from conventional hacking methods. In several instances, the attackers achieved privileged access within three hours of their initial targeting. This rapid escalation was driven by ARTEX, a system of large language model agents designed to run autonomous penetration tests. The framework handled scanning, reconnaissance, and password spraying with minimal human intervention, leaving defenders with scant time to react.

The attackers also employed aggressive automated password guessing against 327 accounts spread across eight organizations. This campaign resulted in over 151,000 failed logon attempts, with no reported successes. At its peak on October 11, the operation generated 2,900 attempts per minute. Nearly 98% of these activities were eventually locked out, yet the sheer volume overwhelmed detection systems. The targets included sectors such as aerospace, defense, semiconductors, government, and think tanks.

Security firm Huntress observed specific malicious behaviors within affected tenants. On October 15, an application added itself to the top administrator role, a behavior that triggered alerts in Microsoft Defender. The attackers also planted new secrets set to expire in 2028. By October 16, unauthorized sign-ins were confirmed for 162 tenants, a number that surged to almost 1,000 the following day. More than 300 of these sign-ins succeeded, indicating that the automated agents were effectively navigating tenant structures.

The use of ARTEX represents a notable change in threat actor methodology. The framework, which can integrate various AI models, has been linked to other recent breaches, including incidents at South Korean financial institutions. The developer of ARTEX, known by the handle Autumn-27, announced on GitHub that the project will cease updates and transition to closed source. This move may impact the broader ecosystem of open-source security tools and the tactics of other state-sponsored groups.

ConnectWise has suspended several of its services, including Cloud Backup and SaaS Security, as a precautionary measure. The company has begun a phased restoration process, with full recovery expected to take several days. There are currently no indicators that partner backup data was compromised. Microsoft advises customers to keep affected application connections disabled until formal instructions are issued and to review activity logs from this month where possible. The incident highlights how AI-driven agents can compress the timeline of a breach, forcing organizations to rethink their detection and response strategies.