tfa.one

Security and privacy

two-factor authentication sharing

SHOW HN2021

tfa.one

Generate shared 2FA codes for your entire team

tfa.one

#shared 2fa#totp#team authentication#slack bot

49points
41comments
#866of 2,533 in 2021
Top 35%of 2021 by points

How HN took it

RoastedHalf or more of the comments are critical

3 positive, 5 neutral or asking, 1 mixed, 12 critical, out of 21 comments about the project. Thread score -0.40.

Idea: 3 for, 6 againstPrivacy: 0 for, 6 against

The thread, comment by comment

Each row is a top-level comment and its replies, in HN's order. Select a cell to open that comment on HN.

positive neutral or mixed critical about another commenter or something else the maker

What HN said

What people liked

  • Useful for shared test accounts and cheap team access.

    From 2 comments
    • This is absolutely perfect for a use case that I've seen a lot: shared test accounts. Eg our app connects to external service X, so we have a staging account set up such that the…
      fishtoaster on HN
    • Yep! I use that with my personal 1password. And honestly, that's probably the way we'll go eventually, but right now we're a super tiny startup - setting up a team 1password and…
      fishtoaster on HN
  • Slash command avoids posting codes in a public channel.

    From 1 comment
    • One conscious decision made when building this was not to blast 2FA codes inside some channel where potentially anyone can see them, which would indeed be pretty bad when users…
      hansy on HN

Objections

  • Gives a third party the TOTP secrets, a risky trust placement.

    From 3 comments
    • Totally get the use case for this, lots of shared accounts in IT, been a problem for years that gets solved in a number of ways. Sometimes clever, sometimes barely duct tape.…
      ShakataGaNai on HN
    • Like most of the services popping up around 2FA, now that 2FA is popular: this essentially removes one of the factors. Whether you're making one of the factors available to…
      remram on HN
    • Most people have their phone as a 2FA device, but they will login to websites/services on their phone anyway. Would you suggest preventing logins from phones? The REAL benefit of…
      tedk-42 on HN
  • Slack as a delivery channel adds another attack surface.

    From 3 comments
    • Not just that... you're also sending those 2FA codes through yet another third party service (Slack), so you have two places where your security can be compromised.
      tgsovlerkhgsel on HN
    • I get the use case, but I just can’t get behind using software like this for security reasons. It’s too easy to add users to slack, leading to accidentally exposing secrets.
      joshdev on HN
    • Using a separate device (yubikey, mobile phone, etc) is always recommended, but this is a bit more secure than meets the eye. Someone would have to get access to your Slack…
      hansy on HN
  • Shared codes defeat the purpose of 2FA and weaken accountability.

    From 2 comments
    • The use case seems to be to bypass any value provided in using 2FA in the first place...
      tossaway9000 on HN
    • Where does non-repudiation fit in if multiple people get the same 2FA code? You're trusting teamFA, Slack, and each team member's Slack accounts. This seems like a security…
      whoknew1122 on HN
  • Lacks an audit log.

    From 1 comment
    • I can see the use case in this (even though it entirely defeats the purpose of 2FA) but one glaring omission I see on the homepage screenshots is the lack of an audit log. I…
      jeroenhd on HN
  • Shared TOTP codes collide when several users log in at once.

    From 2 comments
    • It doesn't say, but I presume these are TOTP codes, and there is just a single generator that you're sharing and thus one shared secret. This has some surprising consequences,…
      tialaramex on HN
    • Yup this is indeed a limitation in that once a code is used, the next person essentially has to wait at least one minute before they can get another working code. My target is…
      hansy on HN

Requests

  • Add an audit log of who requested codes.

    From 2 comments
    • I can see the use case in this (even though it entirely defeats the purpose of 2FA) but one glaring omission I see on the homepage screenshots is the lack of an audit log. I…
      jeroenhd on HN
    • At the moment I don't log/track anything (I don't even store user emails), but I can see an audit trail being extremely useful. Thanks for the suggestion!
      hansy on HN

Questions

  • Can the TOTP seed be reconstructed from codes?

    From 1 comment
    • Is it possible to reconstruct the seed (or some equivalent that would allow you to generate future codes)? If yes, how many codes would you need to do so?
      cmeacham98 on HN

Alternatives named

  • 1Password shared vaults with TOTP fields.

    From 3 comments
    • Do you know 1password handles storing mfa codes?
      auslegung on HN
    • Can't the login with 2FA be shared with the team in 1Password, because 2FA alone is not enough to share a login. Not that sharing logins is a smart thing to do, but people still…
      nikolay on HN
    • For that one vital service which doesn’t support multiple users on a single account (or locks it away behind an eye-wateringly expensive enterprise plan). Every org has one, for…
      jon-wood on HN
  • Bitwarden and Vaultwarden with shared TOTP.

    From 2 comments
    • Bitwarden does this too
      weird-eye-issue on HN
    • Bitwarden, and the fantastic rust-built equivalent Vaultwarden can be self-hosted, include granular, multi-user sharing of credentials which may contain TOTP secrets. The web…
      jeffalyanak on HN
  • LastPass TOTP support.

    From 1 comment
    • Totally get the use case for this, lots of shared accounts in IT, been a problem for years that gets solved in a number of ways. Sometimes clever, sometimes barely duct tape.…
      ShakataGaNai on HN
  • HashiCorp Vault TOTP secrets engine.

    From 1 comment
    • Would recommend hashi vault in place of this which can work for human/non-human workflows and a pretty robust security model with better auditing and authorization than slack.…
      weirdo28 on HN

Category, keywords, summaries and labels on this page were made by AI (Thread Reader v2) and not checked by hand. Each point links to the comments it came from.

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