Weebly and Foursquare are the latest in a long line of tech companies under scrutiny for their security practices. On Thursday, breach notification site LeakedSource posted details of the attacks in a blog post explaining what happened.
More than 43.4 million accounts were stolen in the attack, thought to have been carried out in February.
According to a sample of the data seen by ZDNet, each record in this mega breach contains a username, email address, password, and IP address. Stolen passwords were stored with bcrypt, a strong system for scrambling passwords.