It management company SolarWinds has been hacked, possibly by the Russian government. Us Treasury, commerce, state, energy, and homeland security departments have been affected. The Wall Street Journal is now reporting that some big tech companies have been infected.

Solarwinds had stated that’fewer than 18,000′ companies were affected. It even attempted to hide the list of clients who used the malware.

It can take a long time for the impacts of a hack to be fully realized. Once hackers are inside a system, it can be difficult to tell if they’re fully gone.

In this case, investigators have a lot of data to look back through. The hack is still ongoing and has been for months.

This attack, dubbed supernova, was thought to be part of the main attack. Investigators now think it was executed by a second, less sophisticated group.