Twitter has revealed a little more detail about the security breach it suffered earlier this month when a number of high-profile accounts were hacked to spread a cryptocurrency scam — writing in a blog post that a “phone spear phishing attack” was used to target a small number of its employees. Once the attackers had successfully gained network credentials via this social engineering technique they were in a position to gather enough information about its internal systems and processes to target other employees who had access to account support tools,…