My phone died a few days ago, and the Cisco Duo app overwrote 2FA key backup after connecting my old phone to the internet.
Lemmy has no backup codes, nor can you disable 2FA even while logged in without a valid token.
Anyway, I noticed there’s no rate limiting on 2FA attempts.
So following Lemmy API docs I wrote this exceptionally stupid script (look at my foolish way of parallelization and no auto-stop).
I got the JWT token from logged-in Firefox session, using cookies.txt extension to export it.
Anyway, just make sure your password is secure enough, It’s obviously (potentially) better than 6 digits, probably with 3 valid combinations at each time (current 30s, past 30s, future 30s windows), if I am guessing how it works right.
My attempt also clearly involved a lot of luck with just 21,830 attempts (less than 5 minutes). But, if you’re lucky enough, you may guess it on first attempt, or never if you aren’t.
Anyway, I noticed there’s no rate limiting on 2FA attempts.
Well that’s mildly horrifying… May as well not even have 2fa. Especially with no failed auth attempt notifications (well, no notifications at all really; I hate this part of lemmy)
Glad I don’t have/keep anything private here.
Not do downplay this issue, but based on the description, OP had a valid session cookie, and was updating their profile to disable MFA since they lost the code. They weren’t brute forcing logging in.
I haven’t looked into the source code, maybe this is an instance by instance configuration, but login attempts are rate limited. After a few failed attempts, I started getting this message:
Lemmy Error: You’re being rate limited, wait a bit before trying that again.
I just did a manual test with sh.itjust.works comparing it to lemmy.blahaj.zone.
sh.itjust.works keeps accepting attempts
lemmy.blahaj.zone blocks after I think 3 attempts (I forgot to pay attention)
lemmy.ml also blocks after 3 attemptssh.itjust.works and lemmy.blahaj.zone even use the same version, lemmy.ml is on a 0.19.6 beta.
Going further, lemmy.world: no blocking (as far as tested)
lemm.ee: no blocking (as far as tested)
sopuli.xyz: after 10 attemptsSummary: SDF is using old version, the rate limiting seems to be variable suggesting a setting
Analysis: lemmy.ml, lemmy.blahaj.zone and sopuli.xyz appear to be exposed directly (.zone doesn’t respond without SNI, other 2 show NGINX page). NGINX can pass client IPs in headers. The rate limiting appears to be IP-based.
sh.itjust.works, lemmy.world and lemm.ee are all behind CloudFlare.Hypothesis: Either a problem with passing client IP headers from
cloudflaredor the instance admins simply trust CloudFlare to provide some rate limiting.
Hell yeah
This is like the time I forgot the password to my LUKS drive and started brute forcing it using john and a custom password generation function.
I didn’t get nearly as lucky as you, it took around 18 hours, but I got in. Which was lucky since that luks drive had the sole 512 byte key to my long-term storage drive that had important paperwork on it.
Did you still remember lots of your password parameters, or was it just really short to be solved that fast?
I remembered about 60% and I knew the general format of the password. It was about 30-40 characters in length so it was far from short. I couldn’t remember one of the words, the numbers, or the symbols, nor could I remember the order of the numbers and symbols since I diverted from the pattern I used to use due to the significance of the password.
I made a custom dictionary, and used john with a custom generator to make it fit the possible format of my password so that is why it was so fast. Had I not done that, it probably would have been feasible. It was also an older less secure luks partition so that helped a ton, and the fact I had a mediocre gpu (2070max-q) was the icing on the cake.
I intentionally keep no copies of my encrypted drive passwords so I was fucked if I couldn’t remember the password.
Next time save the secret string on a password manager like KeePassXC to syncronize the files to your PC
Yeah! Defeat the dragon of phone 2fa by putting all your secondary passwords on the cloud, synced to your computer! That’ll show em :D
KeePassXC is offline, it uses local storage
If you sync it it isn’t offline by definition. Might not have to be on google/one drive, but has to be acessible over some network (probably even the internet).
Syncing can be through a peer to peer protocol such as sync thing where both devices would need to know each other’s Device IDs, and the Device IDs are basically just SHA256 hashes of locally generated keys.
Or if the user uses a program to sync over the local network or over USB it’s not necessarily online
You mentioned cloud, and that’s really not needed. If you need sync, you can use a P2P service like Syncthing, and while your data is transmitted over the Internet, any threat actor would need to
a) identify your device IDs and intercept your traffic b) crack the encryption of the network traffic c) crack your password d) (if you used a key file, crack that as well)
If that is not safe enough for your threat profile, sure, don’t use a password manager, but at that point you got bigger problems
