On December 23, 2015 a power-outage occurred in the Ukraine, which affected around half of the homes in the Ivano-Frankivsk region. After the outage, malware was found at several of the regional distribution system operators (DSOs) involved. This has led to a suspicion that the outage was caused by a cyber-attack.
This report provides a summary of what is currently known about this incident. Researchers are still analyzing what happened exactly. So the information is still incomplete, and partly a conjecture.