I reported an insecure DKIM key to Deutsche Telekom / T-Systems.

[diziet@mastodon.me.uk]

@badkeys
Not the same at all, but here are most of my dkim private keys https://www.chiark.greenend.org.uk/dkim-rotate/README.txt

[selea@social.linux.pizza]

@badkeys

What wat. they published the private key?!

[artlog@agora.l0g.eu]

@badkeys

I don't remember have ever seen lower RSA keys size than 512 bits... We have a winner here !

[bekopharm@indieweb.social]

@momo Hab mich damit auch schon herum geärgert und mit einem "Musterbrief" frei gekauft: https://beko.famkos.net/2023/06/02/%c2%b7t%c2%b7%c2%b7%c2%b7error/

Die haben doch echt nicht mehr alle Latten am Zaun o0

[kramse@helvede.net]

@selea @badkeys

no, sounds like they stayed for tooo long on a short length that could be cracked quickly.

they should upgrade to more bits, and re-roll their keys

[janet_catcus@hachyderm.io]

@buherator @badkeys @mcr314 probably done by an apprentice anyway

[badrihippo@fosstodon.org]

@Diziet never even thought this could be a thing!

So you're basically making it impossible to prove through DKIM signatures that a given email was actually sent from your server?

@badkeys

[linear@nya.social]

@badkeys@infosec.exchange just a few days ago i broke an rsa384 key using yafu on my home server (a ~6 year old dell poweredge, fairly decent spec) as a practice run for something, and it took under 5 minutes

[linear@nya.social]

@badkeys@infosec.exchange the yafu help describes using siqs for this, which would take that server 2 to 3 hours, but using nfs it took only minutes

[momo@social.linux.pizza]

@bekopharm
Ich konnte sie auf ein Kontaktformular runterhandeln, musste aber versichern, dass der Transport dann nicht per eMail erfolgt. Ich habe ne ntfy-Instanz auf einem meiner Server laufen, das Webformular generiert jetzt eine Notification auf mein Smartphone.

Eigentlich wollte ich den Zugriff per Firewall auf die Admin-Netzwerke der Telekom zumachen, aber das war für sie absolut inakzeptabel.

Aber bei jeder Gelegenheit seine eigenen Kunden in Geiselhaft nehmen und rumprotzen, dass sie der größte Provider Deutschlands sind und damit eigene Regeln festlegen können, an die sich jeder zu halten hat.

[m_berberich@chaos.social]

@oscherler @tanja

Or they did not understand the problem?

[yama@tech.lgbt]

@lunareclipse @badkeys "bad companies", so most of them by nature ?

[yama@tech.lgbt]

@badkeys RSA ?
You can literally get an API key for your python script to access a literal quantum computer. And someone already made shors alg. implementation exclusively for RSA cracking

If it were over 4096 bits its still Not Secure and crackable within seconds.
Literally Any modern post quantum algorirthm is orders of magnitude better...

[diziet@mastodon.me.uk]

@badrihippo @badkeys Yes.

Everyone should be doing the same (rotating DKIM keys and publishing the old private keys). Here's my blog post on the subject:

https://diziet.dreamwidth.org/16025.html

[x0r@mamot.fr]

@badkeys Modern DKIM implementations should not accept signatures made with RSA keys smaller than 1024 bits, nowadays, so it seems unlikely to me that you could do anything nefarious with a key this weak. The verifier would be equally faulty if it accepts weak keys.

See also: https://www.rfc-editor.org/rfc/rfc8301#section-3.2

[woffs@fe.disroot.org]

@badkeys hot take: dkim does not matter anyway

[wpalant@infosec.exchange]

@badkeys Way to go Telekom! Last time I found a 320 bit RSA key it was “protecting” people’s private information (https://palant.info/2023/01/25/ipinside-koreas-mandatory-spyware/#how-is-this-data-protected) and I even had a little difficulty finding a cryptography library that wouldn’t refuse working with a key so short.

[trpalesz@mastodon.social]

@16af93 @q @badkeys iirc BSA recommends at least 3000bits

[varx@infosec.exchange]

@yama @badkeys Out of curiosity, what year are you posting from?

[yama@tech.lgbt]

@varx @badkeys Im not arguing with internet strangers. Go dive off a bridge mate