A complete bypass of eMudhra’s 1FA OTP login system

(mastodon.catgirl.cloud)

187 points | by tensegrist 1 day ago

21 comments

  • ignatella 1 day ago
    I understand it in the following way:

    They put the public key into js and encrypt the body of the request. This is common practice to protect users' important data from being accessed by a proxy (in this case, Cloudflare) and is ok.

    But the real bug is that they don't rate-limit, invalidate, or protect the endpoint related to OTP checks, so it can be brute-forced, as the search space is limited.

    • ignatella 1 day ago
      so not sure why the author shows us the public key
  • jttnr 1 day ago
    Oh man, good that they are leaving the CA business.

    https://news.ycombinator.com/item?id=50195110

    • chrisjj 1 day ago
      That has no effect, since the'd get no such business from now.

      What's sad it they won't be taking their certs with them. Let's hope the powers up the chain conduct some deep self-refection on their part in thus fiasco.

      • dualvariable 1 day ago
        > Let's hope the powers up the chain conduct some deep self-refection on their part in thus fiasco.

        that almost never happens.

        stop hoping corporations grow a soul and a conscience.

        • Georgelemental 1 day ago
          Who said anything about soul or conscience? Getting hacked doesn't deliver value for shareholders
        • greenavocado 1 day ago
          > stop hoping corporations grow a soul and a conscience.

          stop anthropomorphizing social constructs (corporations). corporations are run by humans. it is the humans running them that lack conscience and a soul.

          • ProllyInfamous 1 day ago
            In America, Corporations are people, too (for serious, see Citizens United SCOTUS ruling).

            But corporately-suited Homo sapiens* should definitely be held criminally liable for much of their intentional shenanigans...

  • buildbot 1 day ago
    So basically anyone who used this CA is screwed if someone knows your email?
    • gruez 1 day ago
      Only if they're lazy and went with the "download key and certificate (and we'll generate the keys for you)" option. Otherwise at least how it's supposed to work is that you give a CA a certificate signing request (CSR) containing your public key, they sign it and hand back your certificate. The certificate itself doesn't contain anything sensitive, because it's the same thing that your server presents to clients. But people are lazy and might not know how to generate a csr locally, hence the aforementioned option. And of course if they're too lazy to generate a csr locally, they're probably also too lazy to keep backups, so you can be sure that eMudhra keeps a copy in case they deleted it from their downloads folder.
      • pdpi 1 day ago
        With this exploit, what's stopping me from sending my own CSR for your domain?
  • hoherd 1 day ago
    The number the tool found was 1861. The e-mailed OTP code was 1858. What am I missing?
    • molticrystal 1 day ago
      I noticed that as well. Figured it was a concurrency issue, and they have a follow-up message that you can see if you click on the OP of the Mastodon thread that confirmed my guess: https://mastodon.catgirl.cloud/@49016/117476097901925573

      >(yes the code is off by a few. its bc the poc is shit and to speed it up it uses 8 connections at the same time. it just stops the counter once it has a hit so its off by ~4 lmfao. you could easily fix this but cba today)

  • TazeTSchnitzel 12 hours ago
    Does anyone understand what's going on here? They expect some kind of request to be signed with a certain key, but what is that request and what does it get you?
    • vbezhenar 12 hours ago
      I guess they just bruteforce OTP by sending all combinations of four digits to the server and eventually one works.
  • tommica 1 day ago
    Could someone explain this? Does this mean that it enables logging in as any account in emudhras infra?
    • cyberpunk 1 day ago
      Yes, it’s a complete auth bypass. All you need is the email address of a user and they’ll likely sign CSRs for any domains under that account.

      It’s the end for them, I imagine.

  • vinckr 12 hours ago
    I'm getting blocked or rather served nonsense because the site thinks I'm an AI scraper :/

    I guess this is normal now

    • antonvs 11 hours ago
      It worked for me just now, and I'm on mobile internet which gets blocked more often than landline connections.
  • _ache_ 12 hours ago
    eMudhra may be exiting the global SSL/TLS certificate business, but that won't fix its security culture. It's not even 2FA, it's 1FA.
    • antonvs 11 hours ago
      If anyone can guess or brute force the factor, it's approaching 0FA.

      It's like fractals, not all dimensions are integers. If your one factor is extremely weak, then it's really only 0.x of a factor.

  • FLeXMurphy 1 day ago
    Security represents less than 1% of their business.
    • lenerdenator 1 day ago
      Aye, but it'll now represent much, much more than 1% of their corporate reputation.
    • chrisjj 1 day ago
      Purported security, you mean.

      Actual security, add some zeros ;)

  • tossit444 11 hours ago
    Blocked link, thanks AI!
  • skeledrew 1 day ago
    I guess certs isn't the only thing they'll be exiting.
  • cyberpunk 1 day ago
    Don't piss off the internet, there will be consequences. I guess.
  • gilrain 1 day ago
    This site serves me garbage. Iocaine, I think? I use Brave.

    "If you are not [a bot], and you feel you have been served garbage by mistake, please contact the owner of the site you're visiting."

    If anyone knows another way to access the content, I'd be interested. No contact details are offered and visiting mastodon.catgirl.cloud resets my connection.

    • jwilk 1 day ago
      You can use https://github.com/jwilk/zygolophodon to read Mastodon posts in your terminal:

        $ zygolophodon --with-ancestors https://mastodon.catgirl.cloud/@49016/117475976434068995
      • fc417fc802 1 day ago
        Doesn't that also fetch the content directly? So depending on the logic of the filter it likely won't make any difference.
        • jwilk 1 day ago
          It uses the API, which hopefully is protected from bots less fiercely.
    • swiftcoder 1 day ago
    • fc417fc802 1 day ago
      Ah yes, adopting the standard cloudflare approach. "Contact the site administrator to resolve this" but no contact details are provided.
  • VladVladikoff 1 day ago
    Hahahahha what a roast. Too funny, especially the "4 Bars" in the background of the demo.
  • trallnag 1 day ago
    Damn, these Mastodon accounts are a rabbit hole to get lost in
  • baal80spam 1 day ago
    "S" in "eMudhra stands for "Secure".
  • EQYV 1 day ago
    Please can this not be true..
  • bragr 1 day ago
    The anti AI scraping on this site doesn't work that well. I'm being served non-sense text about buttplugs. I'm human, I swear.
    • Muromec 1 day ago
      That was proof of soul check and you passed
    • evulhotdog 1 day ago
      I got the same, on a residential internet service. No idea what the trigger is, worked on my phone though.
    • ronsor 1 day ago
      anti-AI scraping is often anti-privacy in practice, as any effective implementation requires invasive browser inspection to detect scrapers.
      • esseph 1 day ago
        The web is for bots now. Humans are the minority and will get pushed out, or leave in the face of various pending identity verification schemes to get past the bot filters.
    • doubled112 1 day ago
      That's what comes after the verification can.
    • paimapi 1 day ago
      that's actually the exploit, it was very physical
      • nathancahill 1 day ago
        We're living in a South Park episode.
  • bigfishrunning 1 day ago
    [flagged]
    • BigTTYGothGF 1 day ago
      Coward.
    • _def 1 day ago
      You should be able to open the url in any other mastodon instance where you are signed in
    • codeduck 1 day ago
      so use your phone?
    • sgsjchs 1 day ago
      weak aura
    • OptionOfT 1 day ago
      There was an post about something like this a while back on lobste.rs, where some people were upset about the image that Anubis shows while it is validating your machine.
      • _def 1 day ago
        People are so uptight, it's embarassing
      • CodinM 1 day ago
        I mean, they do accept money to give you a version without that.
  • greenavocado 1 day ago
    Cut the undersea cables already
    • ProllyInfamous 1 day ago
      I gave up cell phone service a few years ago (mid-sized USA city).

      This seems less-and-less extreme, daily. Free yourselves from your leashes!

      ----

      Next time you're standing in line, strike up conversation (about anything) with your ugliest linemate (it doesn't even matter about what, just offline communication)...

      Maybe ya'll both like ZFS or "heard about that PHP thing!?" (I used both conversation starters, today – it worked – I can be the ugliest, too).

      • danielbln 1 day ago
        Please don't, not everyone appreciates small talk.
        • ProllyInfamous 16 hours ago
          Please express this succinctly when talkers like me "get going" – I appreciate that not everybody wants these brief connections (you won't hurt my feelings with a simple "hey I'm not really much for talking").

          If you prefer wordless silence, pulling out a phone (or book/magazine) works well when talkers "don't take the hint;" or face away (for particularly invasive conversation starters).

          My hope is that small talk leads to shared connections, perhaps even (a brief intertwining of) humanity.

  • Sphax 12 hours ago
    Is this site blocking users coming from HN or something ? I'm getting a garbage page starting with "Face, those cold eyes, and the pale people; I like them if we have."