AI-Powered Hackers Breach Thousands of Corporate Tenants in Hours
A China-aligned threat group used autonomous AI agents to exploit a supply chain weakness, granting privileged access to critical infrastructure sectors with minimal human intervention.
By Robert Hayes ·
The digital landscape is shifting as attackers increasingly rely on automation to outpace traditional defense strategies. Microsoft has detailed a sophisticated supply chain campaign that leveraged artificial intelligence to breach thousands of corporate environments in a matter of hours.
The primary driver of this operation was the use of ARTEX, an open-source framework for agentic AI penetration testing. This tool allowed the threat actor to conduct autonomous reconnaissance and exploit vulnerabilities without constant human oversight. The speed of execution meant defenders had very little time to detect and respond to the intrusion.
The attack targeted the ConnectWise platform, a multi-tenant application that serves as a bridge to customer environments. The group attempted sign-ins at more than 2,250 Microsoft 365 tenants using stolen application credentials. These credentials allowed the attackers to authenticate as the apps themselves, bypassing the need for interactive user logins.
In several cases, the group achieved privileged access in less than three hours after initial targeting. Automated password guessing campaigns also struck 327 accounts across eight organizations. These efforts resulted in over 151,000 failed logons, with no successful breaches via this method, though the scale of the attempt was significant.
The targeted sectors included aerospace and defense, semiconductor manufacturing, government agencies, and think tanks. Microsoft confirmed that the activity did not stem from a vulnerability in its own systems or products. Instead, it was a direct result of unauthorized access to the third-party ConnectWise application.
Huntress, a security firm, observed specific behaviors in one tenant on October 15. They noted an application adding itself to the top administrator role. The attackers also planted new secrets set to expire in 2028, suggesting a long-term persistence strategy. By October 17, unauthorized sign-in activity was detected in nearly 1,000 tenants, with more than 300 instances succeeding.
The pattern of the attack, moving through tenants in sorted order with seconds between attempts, indicated a script working from a predefined target list. This methodical approach contrasts with many traditional attacks by relying on a flexible AI framework that can utilize various models. Public reports have linked similar ARTEX usage to recent breaches at South Korean financial institutions.
ConnectWise suspended several of its cloud services as a precautionary measure. A phased restoration process has begun, with recovery expected to take several days. The company has not found indicators that partner backup data was compromised. Microsoft advises customers to keep affected app connections disabled until formal instructions are issued.
The developer of ARTEX, known by the handle Autumn-27, announced that the project will no longer be updated and will become closed source. This move may impact how other threat actors utilize the framework in future campaigns. For now, the incident highlights the growing speed and autonomy of AI-driven cyber operations.
Source: Tom's Hardware
