GnuPG — "SKS Keyserver Network Under Attack":
"If you fetch a poisoned certificate from the keyserver network, you will break your GnuPG installation."
"High-risk users should stop using the keyserver network immediately."
Temporary replacement can be keybase.io till SKS gets stable fix/replacement.
keybase.io is not a viable replacement. There are a lot of important keys (i.e. distro keys, signing keys for other software, …) that simply don't fit into the keybase model.
Also replacing something decentralized with something centralized especially in this (*hehe*) key position is a really bad idea.
There are various alternatives to the official SKS keyserver implementation, not perfect, but definitely better, because organisations can run it themselves.
Well, first of all, there is WKD, which, to be fair, is not a keyserver implementation by itself, but great for key exchange.
For keyserver implementations I'm thinking of things like the mailveleope keyserver, which isn't doing this background sync that SKS servers do, but at least self-hostable.
I would still prefer WKD to find wider adoption.
Sorry for the necro-reply but SKS has no chances of revival.
Do check out https://keys.openpgp.org that in some respects is an improvement over SKS. Some projects, such as SecureDrop and NixOS already began their switch to keys.openpgp.org:
FWIW I still prefer WKD when possible (own domain or security conscious group of people such as kernel.org: https://www.kernel.org/category/signatures.html#using-the-web-key-directory) but keys.openpgp.org is good for the rest (generic e-mail providers, etc.)
Both Enigmail and OpenKeychain support WKD for some time (see my PR for OpenKeychain: https://github.com/open-keychain/open-keychain/pull/2314).
Recently they both switched to using keys.openpgp.org as the default keyserver as OpenKeychain developer is also behind keys.openpgp.org and Enigmail didn’t have any other choice.
WKD has the advantage of returning third-party signatures (if you care about the Web of Trust), keys.openpgp.org will strip them (this is by design). For a longer discussion see https://blogs.gentoo.org/mgorny/2019/07/04/sks-poisoning-keys-openpgp-org-hagrid-and-other-non-solutions/