Microsoft said today that security vulnerabilities found to impact a web server discontinued since 2005 have been used to target and compromise organizations in the energy sector.

As cybersecurity company Recorded Future revealed in a report published in April, state-backed Chinese hacking groups (including one traced as RedEcho) targeted multiple Indian electrical grid operators, compromising an Indian national emergency response system and the subsidiary of a multinational logistics company.

The attackers gained access to the internal networks of the hacked entities via Internet-exposed cameras on their networks as command-and-control servers.

A major vulnerability in a networking technology widely used in critical infrastructures such as spacecraft, aircraft, energy generation systems and industrial control systems was exposed by researchers at the University of Michigan and NASA.

It goes after a network protocol and hardware system called time-triggered ethernet, or TTE, which greatly reduces costs in high-risk settings by allowing mission-critical devices (like flight controls and life support systems) and less important devices (like passenger WiFi or data collection) to coexist on the same network hardware. This blend of devices on a single network arose as part of a push by many industries to reduce network costs and boost efficiency.

That coexistence has been considered safe for more than a decade, predicated on a design that prevented the two types of network traffic from interfering with one another. The team’s attack, called PCspooF, was the first of its kind to break this isolation.