Building a Secure Electron App | Hacker News Reader

Building a Secure Electron App

github.com

56 pointsbobblywobbles26 comments

It's a great idea to have a template for writing secure Electron apps, but this particular template should only be used with caution. I don't think it has been reviewed or endorsed by the Electron team as actually following those best practices, and I see a few issues just skimming from my phone:

They're trying to expose IPC to the renderer in an unsafe way. See their discussion on this GH issue https://github.com/electron/electron/issues/21437 (referenced from the main readme as blocking some features they want to implement)

On their "building a secure app" page they complain about Electron's quick release cadence https://github.com/reZach/secure-electron-template/blob/mast...

> The trouble that I've found with electron, is that their release schedule is crazy, with only a few months before each major release. We know that electron is a young framework, but it is hard to keep up so quickly!

Electron releases quickly to pull in critical upstream security fixed from chromium. That reasoning is explained pretty thoroughly in the best practices documentation https://electronjs.org/docs/tutorial/security#17-use-a-curre...

I haven't looked at their implementations of the other security best practices, so these might be the only red flags, but I'd still recommend against just blindly copying the template without understanding and verifying the best practices they're attempting to implement.

(author)

Thank you for your feedback. This template has not yet been reviewed but I hope to get candid feedback like yours on spots that may have been missed.

I am planning to change the way the IPC renderer is exposed; Marshall from the Electron team pointed me to a better way of doing so and I hadn't had time to update the repo yet. That will be something I update soon in the code and in the docs.

The best practices I take from Electron themselves; https://electronjs.org/docs/tutorial/security. If there are other security reports please send them to me and the template can be enhanced further.

Is it possible for you to switch your license to something more like MIT or BSD? The work you're doing is great but I believe the majority of Electron apps are developed inside companies and by licensing your project as GPL you make your work into something most commercially employed devs can't touch.

Looks like they just switched to the MIT license (same license Electron itself uses).

(author)

I just did, the repo is now MIT. Enjoy!

If anyone is interested in Electron application security, I wrote a guide that explains the methodology behind some of the choices the author here has taken and even goes a bit further in a variety of areas: https://know.bishopfox.com/research/reasonably-secure-electr...

(author)

Thank you, I will read up on this!

I wish that Safari would support Progressive Web Apps on Desktop like Chrome. I would much rather provide an Application Manifest and Service Worker than building a pseudo native desktop app.

This is based on the Security documentation that the Electron team maintains, which is full of good advice: https://electronjs.org/docs/tutorial/security

For other types of security try https://github.com/tauri-apps/tauri

It is an electron-like framework written in Rust, and is designed to be as lightweight as possible.

Be aware this is GPL licensed

(author)

Is now MIT licensed. I realized after you said GPL that this isn't what I wanted for the repo!

What's wrong with free software?

Nothing, but a GPL-licensed framework is one that is difficult to use commercially, because this is a case where GPL "infects" the user. This use case was the reason for creating the LGPL.

Is it still possible to unpack the asar, rewrite the source, and repackage the asar?

(author)

Yes, it is quite possible to do that. One of my down the road goals is to add light obfuscation to the source code upon packaging. If anyone is motivated, they can break into _any_ source code and repackage.

I'd also like to add some form of checksumming, but again if they have access to the source code they can change anything they want to.

Code signing with a trusted cert is what really helps in this scenario.

It's tough due to platform limitations -- e.g. I think that macOS codesigning will only sign binaries, and your JS/ASAR files are not binaries.

Shouldn't Electron be a "platform" in this case, and provide affordances for that?

It is better to use OS codesigning than hand-built codesigning because then the OS can enforce it -- e.g. App A can't overwrite App B. Anything you hand-roll can be unrolled by an attacker.

I guess my preferred solution for be for Electron to find a way to put the ASAR inside the main binary and find it there and then codesign that, I'm not sure why it hasn't happened yet AFAIK.

It depends what the threat model is. My understanding of Electron apps is that the binary part of the app (Chromium, node, whatever are the parts of the Electron that present the app to the user) is not changing all that often, while web app bits can be updated by simply downloading new version from the publisher's site (correct me if I'm off base here). If this is the case, then the threat here would be the attacker MITM'ing communications between the user and publisher's site and serving malicious payload to the user. Electron validating the signature before serving downloaded bits would mitigate the threat even without OS support (remember - Electron haven't changed, only web app bits have).

Note that I'm saying "Electron validating the signature" - not web app doing that, which I assume what you meant by "hand-rolling".

> Is it still possible to unpack the asar, rewrite the source, and repackage the asar?

Yes, it is still possible — https://github.com/electron/asar

It would be cool to have a regression testsuite showing "insecure" code for each class of security problem, and showing that the problem is fixed by the template.

(author)

That's on my roadmap! Do you have ideas on how a testsuite for that might work? I am open to suggestions.

> Secure Electron App Bit of an oxymoron no ?

/facetiousness

On a lighter note :

> Feature #1

> Only load secure content - (Need help!)

What kind of help? For this template project ?!

(author)

Yes, I need help as I wasn't able to test the security recommendation. I found some snippets but they didn't work when I tested locally.

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