AI-powered hackers breach cloud provider to hit thousands of firms

The intersection of artificial intelligence and cyber defense has created a new tension for corporate security teams. A recent large-scale attack demonstrated how quickly automated systems can move from initial breach to high-level control. The speed of this operation compressed the reaction time for defenders to a matter of hours, highlighting a significant shift in the cost and speed of digital intrusions.

Microsoft revealed that the group, identified as Storm-0940, utilized a tool called ARTEX. This is an open-source framework designed for agentic penetration testing. The attackers used this system to streamline reconnaissance, password guessing, and the abuse of application credentials. The efficiency of the tool allowed the group to execute complex steps with minimal human input. This automation significantly accelerated the timeline of the intrusion.

The financial and operational impact of the campaign was substantial. The attackers attempted to sign in to more than 2,250 Microsoft 365 tenants. They did this using stolen credentials from the ConnectWise platform. In some cases, the group achieved privileged access in under three hours after the initial target was identified. This rapid escalation poses a direct risk to the integrity of sensitive corporate data and administrative controls.

The group also conducted a massive password spraying campaign. They targeted 327 accounts across eight organizations, resulting in over 151,000 failed login attempts. On the peak day of October 11, the system made 2,900 attempts per minute. While almost 98% of these attempts were locked out, the sheer volume of traffic created a significant burden on security monitoring systems. The attackers also successfully signed in to over 200 tenants in less than four minutes using just four application credentials.

Storm-0940 is a China-state-aligned actor that has been active since 2021. The group targeted industries including aerospace and defense, semiconductors, government, and think tanks. Microsoft clarified that the attack did not stem from a vulnerability in its own systems. Instead, it leveraged the compromise of the third-party ConnectWise application. This supply chain vector allows attackers to bypass perimeter defenses by entering through trusted partners.

Security firm Huntress confirmed unauthorized sign-ins for 162 tenants by October 16. By the following day, nearly 1,000 tenants showed activity from the attacking IP address. In one specific instance, an application assigned itself the Global Administrator role. The attackers also planted new secrets set to expire in 2028, suggesting a long-term persistence strategy. The sequential nature of the tenant sweeps indicated that the attackers were working from a pre-sorted list of targets.

The use of ARTEX marks a departure from traditional manual attacks. The framework can utilize various AI models, and other threat actors in different regions are also adopting this technology. Public reports have linked similar tools to breaches at South Korean financial institutions. The developer of ARTEX has since announced that the project will become closed source and will no longer be updated. This move may impact how other groups plan their future operations.

ConnectWise has suspended several of its cloud services as a precautionary measure. The company is working on a phased restoration of its systems, which is expected to take several days. There are no current indicators that partner backup data was compromised. Microsoft advises customers to keep affected application connections disabled until formal restoration instructions are issued. This incident underscores the growing financial stakes of securing third-party integrations in the cloud ecosystem.