I've some experience with gdb and debugging in Linux environment (I'm studying computer science at University and I'm able to handle bof in Linux).
The problem now is on a Windows program. I start it up but after a few seconds a popup appears with the message "You are not connected to the Internet", although I am regularly connected to the Internet. I am trying to parse the assembly code and debug with OllyDbg. First I searched for the string "You are not connected" but I didn't find it anywhere. On closer analysis, I found that the error popup appears when the eip is inside the ntdll dll library and sometimes win32u. I am attaching two screenshots to explain myself better. How do I know where the problem lies? Is it correct to say that the problem lies within a dll? Thank you
With your help, I found the function that calls the MessageBox. But unfortunately I think it is part of a very long loop and it is difficult for me to be able to identify the problem. I was noticing, that when the program starts, the ASCII string "Error writing temporary file .." is loaded. Does it correspond to an allocated variable or is it a message I should see when I start the program? Maybe that's the problem
View->Call stackand you will see window showing you function calls that led to the current one. Just double click on the first address from this list belonging to your exe and you will be redirected to the point where the messagebox function was originally called.