alt Hacker NewsOpenSSH 10.6p2 has been released with a workaround for a critical vulnerability
Comments
> We are making this release as fast as possible (we learned of the problem yesterday) because we have recently observed multiple cases of rapid bug rediscovery by AI agents, sometimes within hours, and so now consider long embargo periods to be a dangerous practice that primarily benefits attackers.
I think this will likely become standard. Nevertheless, a few stormy months are ahead.
Since OpenSSH is included in the base install, and enabled on OpenBSD - is it correct that they will need to update the famous:
“Only two remote holes in the default install, in a heck of a long time!”
musl only, the quick fix:
PasswordAuthentication=no
Is this actually effective against Alpine? The default install seems to use ! as the placeholder in /etc/shadow instead of * and trying the attack doesn't seem to work.
Who does PasswordAuthentication=yes in this day and age anyway.
I would say that PasswordAuthentication=yes is by itself a vulnerability.
This looks terrible for musl, what a collection of terrible decisions on their part. I guess I'm staying away from it.
I'm sure some people running lightweight containers just had a heart attack.
>We consider the root cause of this bug to be outside OpenSSH itself, but we're in a good position to deliver a mitigation quickly.
So not a ssh issue but an issue specific to Linux using "musl libc without PAM".
I presume Dropbear, thus musl-based OpenWrt routers are also not affected? Not that Dropbear has been an example in that regard.
[flagged]
Seems slightly confusing that the OpenSSH release notes page says:
> This release contains a critical security workaround that affects Linux systems that use the musl libc and PAM disabled.
But that there's nothing about it on their security page.
Even if it's not technically a bug in their code, the fact that they've made a "critical" release to address it suggests that it should probably be listed on the security page as well. But maybe (hopefully) they just haven't updated the security page yet.
Wow, what a bug. I expect the exploit is literally as simple as trying to ssh in as a user with the password has ‘*’ in /etc/shadow and typing anything as the password.
To the extent that systems that are configured in the vulnerable manner exist in the wild, I’m surprised they weren’t exploited years ago by trivial ssh bots.
P.S. Wow, I’m reminded of just how awful traditional UNIX-y C APIs and code are.
P.P.S. The musl code in question is nuts. The API it implements is awful. Seriously, here’s the manpage:
https://man.archlinux.org/man/crypt.3.en
You can’t call this function correctly. sshd’s “fix” is basically to assume that a too-short return is an error return instead of a success return.
PAM is also awful, but this is worse.