Jón Hörđdal, chief operating officer at CCP, has responded to last night's service outage with a statement on the developer's website.
"At 17:00 UTC today, CCP became aware of a distributed denial-of-service attack (DDoS) against the EVE Online cluster and web servers," he wrote.
"Our policy in such cases is to mobilize a taskforce of internal and external experts to evaluate the situation. At 17:55 UTC, that group concluded that our best course of action was to go completely offline while an exhaustive scan of our entire infrastructure was executed."
CCP also stressed that subscriber information - including payment details - remained secure and were unaffected by the attack.
"Further, we can also confirm that no personal details such as users' credentials or credit card numbers were exposed through this incident."
An update later in the evening revealed that attempts to flood the EVE Tranquility server with traffic had led to a further withdrawal of the game service, this time instigated by the developer.
While notorious hacker collective LulzSec wasn't named in the statement, the group claimed last night to have targeted the game, along with the log-in servers for indie favourite Minecraft.
CCP is continuing to monitor the situation, and have warned that Tranquility may be taken offline again should circumstances require it.