Mozilla launches Firefox Send for private file sharing

Mozilla launches Firefox Send for private file sharing

Mozilla look to reclaim some ground from the all-powerful Chrome with a new way to send and receive files securely from inside the browser. Firefox Send first emerged in 2017, promising an easy way to send documents without fuss. The training wheels have now come off and Send is ready to go primetime. Will it catch on with the masses, or will only a small, niche group use it to play document tennis?

How does it work?

Firefox Send allows for files up to 1GB to be sent to others via any web browser (2.5GB if you sign in with a Firefox account). The files are encrypted after a key is generated, at which point a URL is created containing said key. You send this URL to the recipient, who is able to then download and access the file securely. Mozilla can’t access the key, as the JavaScript code powering things only runs locally.

Before sending, a number of security settings come into play. You can set the link expiration to include number of downloads, from one to 200, or number of days the link is live (up to seven). Passwords are also available for additional security.

It’s not for everyone

The process isn’t 100 percent anonymous, as per the Send privacy page:

IP addresses: We receive IP addresses of downloaders and uploaders as part of our standard server logs. These are retained for 90 days, and for that period, may be connected to activity of a file’s download URL. Although we develop our services in ways that minimize identification, you should know that it may be possible to correlate the IP address of a Send user to the IP address of other Mozilla services with accounts; and if there is a match, this could identify the account email address.

Of course, there may be even less anonymity if you use the service while signed into a FireFox account to make use of the greater send allowance of 2.5GB.

As a result, this might not be something you wish to use if absolute anonymity is your primary concern.

Who is likely to make use of this?

Send is for situations where you need to get an important file to someone but:

  1. The recipient isn’t massively tech-savvy. If you’re dealing with applications involving a drip feed of documents over time, this can get messy. Eventually, the person at the other end will have had enough of multiple AES-256 encrypted zip files hosted on Box where the password never seems to work, or they don’t have the right zip tool to extract the file. Send will simplify that process.
  2. The person at the other end is tech-savvy. However, they’re not necessarily aware that sending bank details or passport photos in plaintext emails is a bad idea.

A Mozilla project manager mentioned issues involving Visa-related documents in the cloud, and this is definitely where a service like Send can flourish. Multiple uploads over time usually ends up in a game of “hunt the files.” Did you delete everything? Maybe you should leave some of it online in case a problem arises? Are the files really gone if you delete them all, or is it as simple as flipping a “Whoops, didn’t mean it” switch and watching them all come back?

These are real-world, practical problems that people run into on a daily basis. The duct tape, multiple service/program approach works up to a point—and then it doesn’t. Firefox Send is perhaps a bit niche, but there’s nothing wrong with that. Not everyone is a fan of leaving important documents scattered across Google Drive or Dropbox, and this is a handy alternative. We’ll have to see what impact this product has long-term, but having more privacy options available is never a bad thing.


Christopher Boyd

Former Director of Research at FaceTime Security Labs. He has a very particular set of skills. Skills that make him a nightmare for threats like you.