Attack on Tor network reportedly would either completely shut it down worldwide or turn it into evil network. Attack on Directory Authorities (DA), the servers that help Tor clients to find Tor relays in the anonymous network service. These directory authorities are located in the Europe and United States, and maintain the signed list of all the verified exit relays of the Tor network. According to experts, attack on these backbone servers can “incapacitate” the overall architecture of Tor. The targeted servers, according to DNS data, were hosted in a data center in Rotterdam.
Source: https://thehackernews.com/2014/12/tor-network-hacked.html