TOKYO — Sony music sites in Greece and Japan have been hacked, adding to the company’s already throbbing security headache.The attack on the Greek site occurred Sunday, when hackers uploaded a user database to the Internet that includes usernames, real names and email addresses of approximately 8,500 users. The Japanese site was breached on Monday by the hacker group Lulz Security. The group posted a message to its Twitter account with a link to two Sony databases while teasing “stupid Sony” for its lax security. The databases did not contain personal info of site users, however. Sony suffered its first major security breach in April, when hackers accessed the personal details of nearly 100 million subscribers to its online game and music services. Since then the company has been hit by other attacks while spending an estimated $171 million to fix flaws, restore downed services and compensate affected users.