Is it bad to expose the 2FA codes?
In a few weeks I'll do a workshop about security for people who are tech illiterate, I plan to teach about password managers and 2FA.
If I show the 2FA number codes, like the 123 456 ones that I have to paste when required, can that be a possible security breach for me? or is it save since is gonna change in a few seconds anyway?
I'd probably edit a few example screenshots for a purpose like that.
If you really want to show it live on an actual device, then maybe with a throwaway/dummy account
Yea I think that is most valuable as you can include the setup and answer questions people may have. What is obvious to us may not be obvious to them.
Proper, hands-on experience is always best, absolutely
I would assume there aren't any security concerns as:
It's good to keep in mind that while it does improve the overall security of the account, a 2FA/TOTP code can still be phished, so if the user encounters a fake login page and supply his password and 2FA code, it could let an attacker pass the intercepted credentials to the real login page in the background and gain access. Most websites using TOTP will not allow reusing a code more than once in the same time slot, but that's a moot point if the 2FA code is intercepted without being entered on the legitimate website, but in your case of making a demonstration that would not be a security concern.
It's important for the user to ensure they're accessing the legitimate website before typing any credentials and 2FA code.
A safer option nowadays is FIDO2/Passkeys, which will not provide a valid 2FA challenge-response in the case of a spoofed/phishing website, further reducing the possibility of a breach.
2FA (if it’s true 2 factor), each unique code is also challenged against your password and has a lifespan of all but 30 seconds. Wait a minute before showing the slides, they’ll just be useless numbers by then.
They cannot be reverse engineered in some way as to hack any account. At least not to anyone’s knowledge.
Unless there's a super hacker or NSA agent in the class that can figure out your password in real time.. You should be fine doing that.
So NSA agents are the equivalent of super hackers?
Basicly
Make dummy accounts for demos. Will save you a lot of trouble in the future and teach you compartmentalization.
It’s as safe as “leaking” an encrypted document. No one can figure out your TOTP secret unless they brute force it with only a leaked code or two. But if it worries you, you can always change your TOTP secret by going through 2FA setup again.
Also, even if someone knows your second factor, they still need your first factor (your password).
Why would you not have all your demo stuff in a throwaway VE. I would personally just set up a 2FA on something pointless and empty, like a blank proxmox install. Use a separate authenticator for tutorials or just use images that are already out there.
I've entered some 2FA codes about 20 seconds after refresh before, so yeah there is a risk.
is there some useless service that I can use to ser up a 2FA for a demo?
For me I'd put proxmox in a proxmox. get the second one installed with a user then save it as a template. From here you can spin up a new image and use the TOTP services to show various 2FA which include YUBI keys if ever the tutorials get deep. I don't know if there is a 2FA playground as such that just to me seems like a quick low impact way of showing the process. You then just delete that image within the first proxmox install. Hold the phone just searched 2FA playground and it gave me https://pragmarx.com/playground/google2fa#/ which seems perfect for your needs. I can't vouch for the safety of the site but their github is on there so have a browse through
You can setup a Nextcloud instance in a docker and then enable TOTP for the logins. That way, its a separate thing from what you're personally using, and provides a direct analog to the online services that they use. You can even create multiple accounts for your students and have them try it personally.
As you suspect, only during the sixty or so seconds that they are valid.
SMS-based codes tend to be longer lived.
They're useless without your other authentication factors, e.g. login, password.
If you leak one of the 2FA codes, especially together with a timestamp, in theory it allows someone to brute force the seed, since they now have one known plaintext. If you leak multiple, it reduces the amount of time needed to do that.
TOTP ones, no
it's unlikely they are going to be able to bruteforce your 2FA codes in the duration of the class, so just change them back once you're done with the class?
or record the video showing the whole process. change the code, show the video you recorded before the change
Not really