Communications giant Twilio has confirmed hackers accessed customer data after successfully tricking employees into handing over their corporate login credentials.

The San Francisco-based company, which allows users to build voice and SMS capabilities — such as two-factor authentication — into applications, said in a blog post published Monday that it became aware that someone gained “unauthorized access” to information related to some Twilio customer accounts on August 4.

Twilio said since the attack, it has revoked access to the compromised employee accounts and has increased its security training to ensure employees are on “high alert” for social engineering attacks. The company said it has begun contacting affected customers on an individual basis. Full story at TechCrunch.