Returned mail: see transcript for details

[Post Office]

Dear user linux na linux.cz, Mail server administrator of linux.cz would like to inform you that:

We have found that your account has been used to send a large amount of spam during the recent week.
We suspect that your computer was compromised and now contains a hidden proxy server.

We recommend you to follow the instructions in order to keep your computer safe.

Best wishes,
The linux.cz team.