So to close the thread I can say that it seems I have solved my issue.
Initially I tried deleting only the webIF on the infested image and a week passed with no more attacks, but it then started again so it seemed not to have an effect on the outgoing attacks so I believe that there must have been a hidden malware spamming out from it.
After this I tried installing a clean image on the free dual boot slot and waiting now for several weeks it has seemed to quiet down so I conclude now that this has solved my issue and I have now removed the old image.
Thanks for all insights and help given along, it has been much appreciated!