OurMine, the same hackers who claimed responsibility for hacking Facebook CEO Mark Zuckerberg and other celebrities this summer, is leaving a message like this one on each account it successfully hacks:
"Hey, it's OurMine, don't worry we are just testing your security, contact us to tell you more about that."
In every case, the group's access to each target's Twitter account seems to be short-lived. Netflix, Marvel and the NFL have each managed to delete OurMine's tweets -- or else Twitter is doing it for them. The NFL appeared to regain control within 15 minutes of the hack.
According to OurMine, which has been chatting with CNET over email, the hacker group runs into a warning message ("We detected unusual activity on your account") each time it successfully hacks a new Twitter account, suggesting that perhaps Twitter may be automatically flagging the hacks to some degree.
Twitter and the NFL both declined to comment publicly on the hacks.
"We don't know who is our next target," OurMine told CNET.