Yahoo! fails to explain delayed news of 500m data hack, as questions mount on Verizon sale

Markus Jakobsson, chief scientist at Agari, comments: “While there will be speculation around what happened to cause this breach, the reality is these details may not ever be revealed or even truly uncovered by Yahoo! itself. The most likely scenario is that this attack was caused by malware, or the compromise of the account credentials of a user with privileged access to highly sensitive data.”