Originally Posted by Jbrandes
No haha just interested how malware can do things like that. It interests me.
Because answering this question is just riding on the lines of the rules, I can and will only give you a basic answer. I hope that you understand.
For software to remember settings, it must write them to file. No matter how that is done, if the program can change its own settings, the file must be able to be modified. That means that if the setting information is not well protected enough, other software could be designed to modify said file as well.
The better explanation would be an example, but that would be crossing the line on the rules.