samsung – "Attackers in% 1 $ s can atte …" downloads while using the Facebook application

On the night of the 17th, I was using the Facebook application and suddenly a download icon appeared in progress in the status bar. I flipped the notifications screen just in time to take a look at the word "attackers" followed by a bunch of symbols like $ before it disappeared. I could not find anything in the list of download folders, ESET premium was monitoring my phone and all the downloads had not even detected it, and I tried in vain to search online using only the selected phrases I had managed to glimpse.

Then, by sheer luck, today, I managed to find a thread on this problem with all the details. The message was the one in the title of this thread (I can not publish it here because the letter b is in bold) with a download in progress while I use the Facebook application. Which I suppose is completed as "I might try to steal your information" or something like that.

I tried to use this phrase to search it in Google, and although nothing specific to this problem arose, a list of generic information emerged about various types of attacks on the network, DDos, man in the middle and zero-day attacks, which I have really worried about

I still use the phone as it is, I do not really know much about things related to technology. Please let me know what I should do now, if I just turn off the phone or something. The person on the other thread said he had rebooted his phone and that the problem had reappeared when he had logged back into Facebook, so now I'm not sure if a simple factory reset will help and I will probably need to install a custom ROM. something.

I am using Android 7.0 on a Samsung Galaxy J7 Prime. I got a software update for Oreo just one hour before and I wonder if updating the software will help eliminate any malware / spyware / hacking application that has been installed.

Please help me. I have logged into all my accounts through this phone and it has been 4 days since the message appeared. A damage control is needed.

Thank you. If you know anything, anything, please let me know that it is very urgent.