*sshole · sshhole.com
sshhole.com
openssh on musl linux has been letting people into password-less accounts since 2016.

are you affected?

  • is your sshd running on musl? (alpine, openwrt, buildroot, yocto)
  • is it not using pam? alpine’s openssh-server doesn’t by default, or maybe you set UsePAM no
  • are password logins still on? they are by default
  • is there an account with just * as its password? key-only users, ldap users, root on alpine
  • and some other account with a real password?
  • then that * account takes any password between 257 and 1024 characters

on alpine’s official aws and azure images that’s the default alpine user, and it has passwordless doas. so it’s root

on debian, ubuntu, fedora or anything else with glibc? going through pam? dropbear? openbsd? you’re fine

  • GeneralDingus@lemmy.cafeEnglish
    2·
    1 hour ago

    I use alpine with an ssh port exposed to the internet so I can connect to it. This doesn’t seem to be an issue if you configured your settings to be secure.

    Never use just default settings.

  • lntl@lemmy.mlEnglish
    6·
    3 hours ago

    I wouldn’t recommend deploying any ssh server without reviewing the config and believe sane defaults are sane.

  • Possibly linux@lemmy.zipEnglish
    12·
    4 hours ago

    This isn’t nearly as bad as I thought it was. Also the author is very reliant on AI to the point where they didn’t think about what if someone wipes the logs.

    Any effected devices should be wiped and redeployed

  • [object Object]@lemmy.caEnglish
    442·
    6 hours ago

    Jesus Christ. Why?! How?

    Edit: I can’t figure out how to upload gifs to Lemmy… please imagine castle-nathan.gif

  • tal@lemmy.todayEnglish
    13·
    5 hours ago

    did you get hacked? check.

    $ grep “Accepted password” /var/log/messages

    That’s a really bad check unless you have an external box receiving logs and you’re looking there, because the first thing that a sophisticated attacker is going to do if they get in as root is remove the signs of their presence.

  • FiredFloridaCop@lemmy.worldEnglish
    15·
    3 hours ago

    I’m no cybersecurity expert, but from what I’ve heard from those who are, this is the new normal as anyone who formerly had no chance due to being a “script kiddie” can now just prompt an AI* to eventually find a vulnerability.

    * oversimplification redacted

    • colourlesspony@pawb.socialEnglish
      9·
      4 hours ago

      Yep, those new fangled slop-kitties. The worst part is that there brute force hacking is being subsidized by people 401ks.

      • FiredFloridaCop@lemmy.worldEnglish
        4·
        4 hours ago

        The irony - of course - is that their 401k money goes right into hacking those same people’s 401ks.

        … but at least we can brainrot an entire generation with glass fruit slices and put artists out of work?

        Now if you’ll excuse me, I have to go convince someone that the TikTok deepfakes they’re watching aren’t real and that cops don’t really employ nanny-boo-boos to unsettle criminals during interrogations. No, I’m not joking.

    • lemmyvore@feddit.nlEnglish
      5·
      4 hours ago

      It’s not quite as simple as that. The author in this case followed a pretty specific trail to find the bug.

      Where AI helped was as the last step. They already knew what the bug would do and where to look, but actually looking through the source code for all the possible musl implementations out there would have taken a lot of time.

      So they brute-forced it instead and asked AI to spin up actual running instances of all those implementations and simply tried the bug against each of them, rather than looking at all the code.

        • lemmyvore@feddit.nlEnglish
          41·
          4 hours ago

          That’s because it turns out there are tons of vulnerabilities out there introduced by very lazy and/or dumb code.

          It isn’t that AI has lowered the bar for hacking, it’s that it’s showing us just how much bad code is out there. The bar was already on the ground, we just didn’t know it.

          After all is said and done AI will actually end up raising the bar for security everywhere.

          Unfortunately we have a lot of legacy crap to clean first.

          • FiredFloridaCop@lemmy.worldEnglish
            12·
            3 hours ago

            You’re doing mental gymnastics to argue with me. Let’s try what I said worded differently in a way that hopefully helps you realize we agree:

            It is now easier to hack.

    • Encrypt-Keeper@lemmy.worldEnglish
      3·
      4 hours ago

      The way it works is that finding vulnerabilities required a lot of technical understanding and mental effort. A software could have a glaring hole in it for years without anyone finding out simply due to nobody really looking. AI just gives you the ability to do rudimentary exploit analysis around the clock without having to spend your own time. This is a wake up call to anyone making software in sloppy fashion.

      But it isn’t quite as easy as saying “AI hack into this service”, if the person doing the hacking is using the same model as the person who made the service, and that person already asked the AI to do that and fixed the resulting exploit prior to release.

      Even projects that use AI in a limited fashion to code or even not at all, often use AI to at least do some red team stuff prior to release.

      I don’t really foresee any way this doesn’t even out eventually.

  • Orygin@sh.itjust.worksEnglish
    10·
    5 hours ago

    OP I know you’re trying to do good, but please try to understand the vulnerability before spreading FUD

    • smiletolerantly@awful.systemsOPEnglish
      21·
      4 hours ago

      Yeah fair, sorry about that. The intro + where I originally learned this from made me overreact a bit, it seems.

  • tofu@lemmy.nocturnal.gardenEnglish
    25·
    6 hours ago

    I mean, not that it’s not severe, but which container images have ssh baked in? If you’re using good stripped down images, you’re fine here.

    Not sure where the overlap is between"ssh is enabled" and “one of those OSes”. LXCs maybe?

    • lemmyvore@feddit.nlEnglish
      4·
      4 hours ago

      Unless it’s explicitly installed no. The default Alpine image doesn’t come with OpenSSH.

  • tapdattl@lemmy.worldEnglish
    16·
    6 hours ago

    I’m assuming this is only if you allow password authentication? If you’re only allowing certificate based auth you should be safe, right?

      • smiletolerantly@awful.systemsOPEnglish
        212·
        4 hours ago

        NO! Exactly the opposite, that is the problem. Key-only is a prerequisite for this.

        Edit: see also, the first thing that pops up under the link.

        I was wrong, see below.

        • AHemlocksLie@lemmy.zipEnglish
          2·
          4 hours ago

          The “are you affected?” section directly contradicts this. It outright states you must have password authentication enabled. Otherwise, SSH never gives you a chance to even attempt a password.

        • HelloRoot@lemy.lolEnglish
          2·
          4 hours ago

          Bottom of the page says what to do and gives 2 options to mitigate:

          # update. openssh 10.6p2 fixes it.
$ apk upgrade openssh

# can't update yet? turn password logins off.
$ echo "PasswordAuthentication no" > /etc/ssh/sshd_config.d/00-no-passwords.conf
$ rc-service sshd restart

          So if you disable password auth and only allow key auth, then you are unaffected (safe).

          The introis a bit confusing but it means that if you have password auth on - then even if your regular ssh login requires a key, you are not safe.

    • smiletolerantly@awful.systemsOPEnglish
      210·
      4 hours ago

      NO! Exactly the opposite, that is the problem. Key-only is a prerequisite for this.

      Edit: see also, the first thing that pops up under the link.

      I was wrong, see below.

      • cecilkorik@piefed.caEnglish
        8·
        5 hours ago

        I think there is some confusion and potential for misinformation here. SSH in key-only mode (common configuration) protects you from this problem, because it never accepts or even attempts any passwords at all, regardless of length. SSH in password-allowed mode with at least one user who might be a key-only USER by merit of having a password hash of “*” (not a valid password hash) is a prerequisite for this. That is a very different and very common thing, as most systems come with at least one key-only user by default. But gaining access to that user with an incorrect, invalid password still requires having passwords enabled at all.

        To be clear: Password access enabled is a prerequisite, and by extension, password access disabled (key-only) prevents this.

        The website you linked clearly defines that all of these conditions must be true for you to be vulnerable, and as far as I can tell, it is exactly correct:

        is your sshd running on musl? (alpine, openwrt, buildroot, yocto)
        is it not using pam? alpine’s openssh-server doesn’t by default, or maybe you set UsePAM no
        are password logins still on? they are by default
        is there an account with just * as its password? key-only users, ldap users, root on alpine
        and some other account with a real password?

        then that * account takes any password between 257 and 1024 characters

        The * account which they suggest potentially being “key only” is the prerequisite you are talking about, but having SSH itself key-only (which is best practice anyway) prevents the attack entirely.

      • DrakiaXYZ@lemmy.caEnglish
        4·
        5 hours ago

        The linked article literally says you need password login enabled at the ssh level. The account however needs to not have a password set

  • Err(()).unwrap()@lemmy.worldEnglish
    153·
    6 hours ago

    That website is atrocious. It’s the web design equivalent of shoving five kilograms of sugar and whipped cream in a cup of coffee.

      • Err(()).unwrap()@lemmy.worldEnglish
        51·
        5 hours ago

        Yes, it was a stroke of genius to label their mediocre confectionery as “coffee”, although it can lead to near fatalities when someone who’s only ever had Starbucks encounters real coffee for the first time.

        Still, my point stands. That website is like 20% useful content, 40% flair, and 40% wasted space.

    • lagoon8622@sh.itjust.worksEnglish
      2·
      3 hours ago

      “Cyber” ppl love to do this. This is basically their resume I guess? They have to sensationalize absolutely everything they can (not that this isn’t an important bug, but this could have been a 1-2 page white paper imo (like many of them))

  • Venia Silente@lemmy.dbzer0.comEnglish
    6·
    5 hours ago

    If I’m running containers on Alpine, doesn’t that mean that they already don’t offer SSH (sshd)? The entire point of Alpine as a base is to not add stuff you don’t need.

  • tenchiken@anarchist.nexusEnglish
    6·
    5 hours ago

    Everything behind a good firewall and proxy.

    No public facing url should ever not be proxied.

    Only ports you explicitly forward. Ever.

  • InnerScientist@lemmy.worldEnglish
    3·
    4 hours ago

    The only container i have that has a reachable SSH port is forgejo, and even then it’s only local traffic and i’d have to check if it even uses alpine. All others also don’t have SSH enabled.

    The vulnerability doesn’t seem too bad tbh.

    • lemmyvore@feddit.nlEnglish
      2·
      4 hours ago

      I mean, anybody who’s still using password login for SSH is kind of asking for it.

  • Guiorgy@lemmy.mlEnglish
    2·
    4 hours ago

    How is crashing on an unhandled path in a security context not better?!