A three-month study of social media spam has found thatattacks come in waves, with each of the sites experiencing a surge in spam,followed by a peak and a sharp decline.

The study, revealed in a Symantec blog, saw Facebook,Twitter and YouTube all experience the same trend between April and June thisyear.

The average life span of each attack was around 20 days.

Symantec found the most common strategy was to use botnets tosend email notifications from the social networking sites saying the user hasunread messages or pending invites.

A fake link will be provided, and this will direct the userto a harmful website.

Among the most common messages to appear in subject lines werethe phrases ‘Warning: your inbox is full, message not accepted,’ and ‘Hi, you havenotifications pending.’