5 ms·

I was trying to download Linux securely a month or so ago. It's actually embarrassingly difficult to do. The only two distros that did it right (that I could fi

by btrask 11y ago

I was trying to download Linux securely a month or so ago. It's actually embarrassingly difficult to do. The only two distros that did it right (that I could find) are Debian and Alpine Linux. The rest (including Mint and Ubuntu) had hashes (usually MD5) or GPG keys served over HTTP.

chei0aiV 11y ago
If you can think of any improvements Debian could make, please do suggest them via bug reports or on the mailing list. If you would like to work on fixing some of our issues, here are the ones we know about: https://wiki.debian.org/Hardening/RepoAndImages https://wiki.debian.org/Hardening/RepoAndImages
- btrask 11y ago
  Debian is already outstanding in this regard (and others)! One minor suggestion would be to provide ISO hashes over HTTPS. It's just as secure as using GPG with fingerprints sent over HTTPS, and it's a lot easier. The fingerprints (https://www.debian.org/CD/verify https://www.debian.org/CD/verify) could also be made more prominent (perhaps put on the main download page). Thanks again!
- kbaker 11y ago
  Maybe in a GPG-signed release email add magnet URLs for the official torrents. This is kind of in 'No magnet: links for bittorrent downloads on SSL'
bcl 11y ago
Fedora publishes GPG signed SHA256's of the iso's. eg. https://dl.fedoraproject.org/pub/fedora/linux/releases/23/Workstation/x86_64/iso/Fedora-Workstation-23-x86_64-CHECKSUM https://dl.fedoraproject.org/pub/fedora/linux/releases/23/Wo...
- btrask 11y ago
  Thanks! Fedora was one I didn't try (to install; I use it all the time). However there's still no way to use RPMFusion: http://rpmfusion.org/keys http://rpmfusion.org/keys Maybe there's something I'm missing?
  - anaphor 11y ago
    Arch Linux has PGP signatures and is over https, as well as torrents which should be pretty reliable https://www.archlinux.org/download/ https://www.archlinux.org/download/
  - awda 11y ago
    RPMFusion isn't considered part of Fedora. Yes, it would be nice if RPMFusion served hashes securely.
miscellaneous 11y ago
I noticed last year that ubuntu.com - despite being the source from which most people download Ubuntu .isos - has no HTTPS capability and doesn't offer any checksums or gpg signatures on their download page. I believe you can find gpg signatures if you scratch around on their ftp server, but it is ridiculous to assume users will do this (especially when Ubuntu is trying to be a user-friendly distro). Anyway, as a result I ended up emailing their webmaster asking why Ubuntu.com has no SSL cert. and I haven't heard anything back yet. I think it is pretty poor that a company like Canonical can have such a flagrant disregard for basic security practices, especially when it likes to market Ubuntu as a 'secure' OS.
- RaleyField 11y ago
  It's a bit convoluted. Follow this guide - https://help.ubuntu.com/community/VerifyIsoHowto https://help.ubuntu.com/community/VerifyIsoHowto If you are running Ubuntu then you already have signing key (run apt-key list), otherwise you can compare the full fingerprint with the one printed in terminal output in the guide that's hosted on https.
  - btrask 11y ago
    It's on HTTPS, but it's also a Wiki that anyone can edit. This is the most recent change: https://help.ubuntu.com/community/VerifyIsoHowto?action=diff&rev2=24&rev1=23 https://help.ubuntu.com/community/VerifyIsoHowto?action=diff...
cheez 11y ago
Are torrents more secure? I usually use the torrents option.
- kuschkufan 11y ago
  Yes they are. No risk of man-in-the-middle with torrents.
Marqin 11y ago
Arch Linux has HTTPS mirrors and provide their GPG signature on HTTPS site.
emergentcypher 11y ago
What I don't get about publishing the hashes, etc... if they are serving up tampered .iso files, why wouldn't they also change the website to serve the appropriate hashes for the hacked isos? For the verification to work I would think it needs to be PGP-signed and you should have the public key in advance.
antnisp 11y ago
Why is that a problem? If the hash is signed and the public key is trusted shouldn't that be secure?
- cwyers 11y ago
  Because someone can do a man-in-the-middle attack and intercept the right hash and replace it with another one. And how do you verify that the public key is trusted for the first time?
  - antnisp 11y ago
    I was under the impression that you can have your key signed by a generally trusted CA.
    - technion 11y ago
      GPG has no central CAs, but relies on a "web of trust" situation. In reality, there's no one central that everyone trusts, so unless the keys are signed by some individual you personally trust, you're down to being reliant on getting valid keys.

by btrask 11y ago

chei0aiV 11y ago

If you can think of any improvements Debian could make, please do suggest them via bug reports or on the mailing list. If you would like to work on fixing some of our issues, here are the ones we know about: https://wiki.debian.org/Hardening/RepoAndImages https://wiki.debian.org/Hardening/RepoAndImages

btrask 11y ago
Debian is already outstanding in this regard (and others)! One minor suggestion would be to provide ISO hashes over HTTPS. It's just as secure as using GPG with fingerprints sent over HTTPS, and it's a lot easier. The fingerprints (https://www.debian.org/CD/verify https://www.debian.org/CD/verify) could also be made more prominent (perhaps put on the main download page). Thanks again!
kbaker 11y ago
Maybe in a GPG-signed release email add magnet URLs for the official torrents. This is kind of in 'No magnet: links for bittorrent downloads on SSL'

bcl 11y ago

Fedora publishes GPG signed SHA256's of the iso's. eg. https://dl.fedoraproject.org/pub/fedora/linux/releases/23/Workstation/x86_64/iso/Fedora-Workstation-23-x86_64-CHECKSUM https://dl.fedoraproject.org/pub/fedora/linux/releases/23/Wo...

btrask 11y ago
Thanks! Fedora was one I didn't try (to install; I use it all the time). However there's still no way to use RPMFusion: http://rpmfusion.org/keys http://rpmfusion.org/keys Maybe there's something I'm missing?
- anaphor 11y ago
  Arch Linux has PGP signatures and is over https, as well as torrents which should be pretty reliable https://www.archlinux.org/download/ https://www.archlinux.org/download/
- awda 11y ago
  RPMFusion isn't considered part of Fedora. Yes, it would be nice if RPMFusion served hashes securely.

miscellaneous 11y ago

I noticed last year that ubuntu.com - despite being the source from which most people download Ubuntu .isos - has no HTTPS capability and doesn't offer any checksums or gpg signatures on their download page. I believe you can find gpg signatures if you scratch around on their ftp server, but it is ridiculous to assume users will do this (especially when Ubuntu is trying to be a user-friendly distro). Anyway, as a result I ended up emailing their webmaster asking why Ubuntu.com has no SSL cert. and I haven't heard anything back yet. I think it is pretty poor that a company like Canonical can have such a flagrant disregard for basic security practices, especially when it likes to market Ubuntu as a 'secure' OS.

RaleyField 11y ago
It's a bit convoluted. Follow this guide - https://help.ubuntu.com/community/VerifyIsoHowto https://help.ubuntu.com/community/VerifyIsoHowto If you are running Ubuntu then you already have signing key (run apt-key list), otherwise you can compare the full fingerprint with the one printed in terminal output in the guide that's hosted on https.
- btrask 11y ago
  It's on HTTPS, but it's also a Wiki that anyone can edit. This is the most recent change: https://help.ubuntu.com/community/VerifyIsoHowto?action=diff&rev2=24&rev1=23 https://help.ubuntu.com/community/VerifyIsoHowto?action=diff...

cheez 11y ago

Are torrents more secure? I usually use the torrents option.

kuschkufan 11y ago
Yes they are. No risk of man-in-the-middle with torrents.

Marqin 11y ago

Arch Linux has HTTPS mirrors and provide their GPG signature on HTTPS site.

emergentcypher 11y ago

What I don't get about publishing the hashes, etc... if they are serving up tampered .iso files, why wouldn't they also change the website to serve the appropriate hashes for the hacked isos? For the verification to work I would think it needs to be PGP-signed and you should have the public key in advance.

antnisp 11y ago

Why is that a problem? If the hash is signed and the public key is trusted shouldn't that be secure?

cwyers 11y ago
Because someone can do a man-in-the-middle attack and intercept the right hash and replace it with another one. And how do you verify that the public key is trusted for the first time?
- antnisp 11y ago
  I was under the impression that you can have your key signed by a generally trusted CA.
  - technion 11y ago
    GPG has no central CAs, but relies on a "web of trust" situation. In reality, there's no one central that everyone trusts, so unless the keys are signed by some individual you personally trust, you're down to being reliant on getting valid keys.