This leak is a continuation of a previous one from June, when the group dumped email login credentials of Exxon employees. This time Shell, BP Global, Gazprom and Rosneft were hit.
The hackers have also used all of the email addresses to sign Greenpeace's online petition against Arctic drilling, but made sure to say that the environmental organization isn't behind the hack.
They mentioned that they managed to breach Exxon's site due to a mistake of its webmaster, and not by exploiting a vulnerability, but haven't commented on how they compromised the rest of the companies.
"We know we’re going up against the most powerful countries and companies in the world.
But together we have something stronger than any country’s military or any company’s budget. Our shared concern for the planet we leave our children transcends all the borders that divide us and makes us - together - the most powerful force today," the hackers stated, and offered the cracked MD5 hashed for anyone who's interested.