The PlayStation Network and Sony Entertainment Network are back online on Monday following a cyber attack that took it down over the weekend. Sony said the networks were taken offline due to a distributed denial of service attack. Such attacks overwhelm systems with traffic in orer to take them down. It says there is no evidence of any intrusion to the network and no evidence of any unauthorized access to users’ personal information.

In light of the issue, the networks will not undergo the regularly scheduled maintenance, which was planned for Monday, August 25.

"We regret any inconvenience this may have caused," Sony said.

But the cyber attack against Sony's PlayStation Network appears to be part of a campaign against several online gaming services. Microsoft's XBox Live, Blizzard's Battle.net, and Grinding Gear Games also reported being disrupted over the weekend.

Microsoft declined to "comment on the root cause" of disruption its rival Xbox Live online gaming service has faced.

This appears to be a consequence of an attack on Activision Blizzard's gaming service Battle.net, which also supports World of Warcraft and Starcraft titles.

"Battle.net game services have recently been subject to DDoS attacks. We worked diligently along with our ISPs [internet service providers] to improve the situation and currently are seeing more stability," said a message posted to the facility's site.

Grinding Gear Games posted a message on the Twitter account of its game Path of Exile on Sunday, saying: "We're having some server issues due to a DDoS attack. Should have it sorted out soon. Sorry for the inconvenience!"