I need to download some files which are distributed as a torrent. The files aren't pirated / restricted so i dont need to worry about a VPN.

My main concern is securing my computer when downloading the files. Im using a macbook pro running 10.10.5 (all latest patches). Ive also got Avast mac anti virus (free) installed.

My current workflow is : add torrent to transmit (torrent client), set download location to a custom folder, once download is complete run an Avast custom scan on the download location folder. If scan comes back with no results i open the file as normal.

Is there anything else i can do to increase the security of my computer from Viruses, malware and other unwanted issues when downloading torrents ?

  • @danielAzuelos do you mean like a checksum ? If so no. Could you clarify what your referring to by "these" – sam Jun 25 '17 at 19:07
  • Does the source of the files provide a signature (MD5, sha2, gpg...) of these (files)? – dan Jun 25 '17 at 21:15
  • How does a person "open the file as normal"? – techraf Jun 26 '17 at 7:04
  • Even if a checksum was provided there is no guarantee that the original file is not malware. How can you trust the checksum? If it is from a random torrent site you can’t. If it is from a vendor and a bit torrent mirror just happens to be the download method then you can more faith. Even then it isn’t always a sure thing: theregister.co.uk/2016/02/21/… – TheJulyPlot Jun 26 '17 at 7:25
  • @techraf by double clicking the file and having it open in its default programme – sam Jun 26 '17 at 10:39

This assumes you are interested in ensuring the file maintains integrity in transit.

If you have access to the source files before transmit you should run a hash on the files such as sha256 or if they are large then save a litttle time using the older sha1 (depends how much you want to trust the source, md5 might be acceptable for you even)

Keep the hashes safe, when the files are received at the other end recheck the hashes.

Make sure you check at the destination before executing them though!

If you are wanting general security advice then the same rules of downloading any file apply. Such as:

  • Keep up to date AV
  • Execute with minimum privileges needed
  • Keep OS patched

You could also (If you think it's worth the effort) sandbox the downloads (even in its own VM) if you wanted. But I don't know what the files are for so only you will know if this level is needed.

  • how do you execute a file with minimum privileges - if its a pdf or video file (various formats) – sam Jun 26 '17 at 10:43
  • I'm saying make sure you are not logged in with administrative/system level privileges. Just the level you need to get the file/application to do what you need. – ISMSDEV Jun 26 '17 at 11:42
  • ah ok, so create another user account with standard privileges and use the file from there. If i did that would i be able to test if file was malicious and then transfer to admin account (the account i use everyday). How would i be able to tell if the file was malicious, as i guess it could start by running some background tasks or lay dormant for a while ? – sam Jun 26 '17 at 15:21
  • it will not detect if malicious. Depending on you ACL will govern which accounts can do what with the file. It's more of a best practice to run with the min privileges you need. You shouldn't be using an admin account for normal everyday working. – ISMSDEV Jun 26 '17 at 17:00
  • Correct me if I am wrong, but I believe malware exists that can detect if it's running in a VM and try to escape. Also, if the VM is connected to the network, it isn't truly sandboxed, right? – Kolob Canyon Sep 11 '18 at 5:44

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