I reported an insecure DKIM key to Deutsche Telekom / T-Systems.
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I reported an insecure DKIM key to Deutsche Telekom / T-Systems. They first asked me to further explain things (not sure why 'Here's your DKIM private key' needs more explanation, but whatever...). Then they told me it's out of scope for their bugbounty.
I guess then there's really no reason not to tell you: They have a 384 bit RSA DKIM key configured at: dkim._domainkey.t-systems.nl
384 bit RSA is... how shall I put it? I think 512 bit is the lowest RSA key size that was ever really used. 384 bit RSA is crackable in a few hours on a modern PC (using cado-nfs). The private key is:
-----BEGIN RSA PRIVATE KEY-----
MIHxAgEAAjEAtTliQYV2Xvx1OGkDyOL799BTFEuobY2dn2AgtiKCQgrh78NVK1JK
j0yRXgNnPpGBAgMBAAECMF0t+TBZUCi8xATSMij7VLTxv5Xi5OIXesNiXOKtYIRP
LkpYfR5PggaMScfbmqSssQIZAMwOhm9d7Y7Qi7I2j1AlYbiqdtqO54T7FQIZAONa
9dJFkC6lM3EPXR+0SZ4dqwwpiM0nvQIYYgz8thi5JK264ohq9sTvnu9yKvUN9I09
AhgfgMYZKcxtujRjkSZtMzUUNLYzzDmJe90CGDKwqcBI0v9ChaR8WHht+/chMdxj
7ez94w==
-----END RSA PRIVATE KEY-----@badkeys hot take: dkim does not matter anyway -
I reported an insecure DKIM key to Deutsche Telekom / T-Systems. They first asked me to further explain things (not sure why 'Here's your DKIM private key' needs more explanation, but whatever...). Then they told me it's out of scope for their bugbounty.
I guess then there's really no reason not to tell you: They have a 384 bit RSA DKIM key configured at: dkim._domainkey.t-systems.nl
384 bit RSA is... how shall I put it? I think 512 bit is the lowest RSA key size that was ever really used. 384 bit RSA is crackable in a few hours on a modern PC (using cado-nfs). The private key is:
-----BEGIN RSA PRIVATE KEY-----
MIHxAgEAAjEAtTliQYV2Xvx1OGkDyOL799BTFEuobY2dn2AgtiKCQgrh78NVK1JK
j0yRXgNnPpGBAgMBAAECMF0t+TBZUCi8xATSMij7VLTxv5Xi5OIXesNiXOKtYIRP
LkpYfR5PggaMScfbmqSssQIZAMwOhm9d7Y7Qi7I2j1AlYbiqdtqO54T7FQIZAONa
9dJFkC6lM3EPXR+0SZ4dqwwpiM0nvQIYYgz8thi5JK264ohq9sTvnu9yKvUN9I09
AhgfgMYZKcxtujRjkSZtMzUUNLYzzDmJe90CGDKwqcBI0v9ChaR8WHht+/chMdxj
7ez94w==
-----END RSA PRIVATE KEY-----@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.
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@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 crackingIf it were over 4096 bits its still Not Secure and crackable within seconds.
Literally Any modern post quantum algorirthm is orders of magnitude better... -
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@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.
@momo @bekopharm das dreisteste ist es hängt scheinbar stark davon ab welchen Support Mitarbeiter man erreicht. Hab Jahre lang damit gelebt einfach keine E-Mails an t-online senden zu können. Wurde irgendwann dann aber doch zu nervig und ich habe sie nochmal kontaktiert. Dann haben sie ohne große Nachfrage einfach meine IP freigeschaltet
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@momo @bekopharm das dreisteste ist es hängt scheinbar stark davon ab welchen Support Mitarbeiter man erreicht. Hab Jahre lang damit gelebt einfach keine E-Mails an t-online senden zu können. Wurde irgendwann dann aber doch zu nervig und ich habe sie nochmal kontaktiert. Dann haben sie ohne große Nachfrage einfach meine IP freigeschaltet
@j_r
War bei mir ähnlich. Wer seinen Mailkram dann bei der Telekom hatte, hatte halt Pech. Zwischendrin hatte ich deren ASN im Spamfilter geblockt, weil ja, dann halt auch in beide Richtungen. Dann schlug aber der WAF Alarm und da blieb mir keine Wahl mehr... ich hab aber dann wohl beim Support-Lotto das falsche Ticket, gezogen.(WAF= Wife Acceptance Factor)
@bekopharm -
@kkarhan @momo @badkeys @BNetzA @EUCommission Had the same issue just recently. I wonder how this can even be legal.
I wanted to ask a lawyer about this, but never came around doing so.
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@stellated @kkarhan @momo @badkeys It works like this: send an email to a Telekom recipient. Mail bounces with
<xxxxx@t-online.de>: host mx03.t-online.de[194.25.134.73] refused to talk to
me: 554 IP=1.2.3.4 - None/bad reputation. Ask your postmaster for help
or to contact tobr@rx.t-online.de for reset. (NOWL)
Send an email to tobr@rx.t-online.de, hilarity ensues.
(They send a reply pointing you to https://postmaster.t-online.de/#t4.1)
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@stellated @kkarhan @momo @badkeys It works like this: send an email to a Telekom recipient. Mail bounces with
<xxxxx@t-online.de>: host mx03.t-online.de[194.25.134.73] refused to talk to
me: 554 IP=1.2.3.4 - None/bad reputation. Ask your postmaster for help
or to contact tobr@rx.t-online.de for reset. (NOWL)
Send an email to tobr@rx.t-online.de, hilarity ensues.
(They send a reply pointing you to https://postmaster.t-online.de/#t4.1)
@stellated @kkarhan @momo @badkeys Bit more discussion in German to be found here: https://borncity.com/blog/2025/02/25/merkwuerdige-vorschriften-bei-der-telekom-fuer-e-mail-versand/
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I reported an insecure DKIM key to Deutsche Telekom / T-Systems. They first asked me to further explain things (not sure why 'Here's your DKIM private key' needs more explanation, but whatever...). Then they told me it's out of scope for their bugbounty.
I guess then there's really no reason not to tell you: They have a 384 bit RSA DKIM key configured at: dkim._domainkey.t-systems.nl
384 bit RSA is... how shall I put it? I think 512 bit is the lowest RSA key size that was ever really used. 384 bit RSA is crackable in a few hours on a modern PC (using cado-nfs). The private key is:
-----BEGIN RSA PRIVATE KEY-----
MIHxAgEAAjEAtTliQYV2Xvx1OGkDyOL799BTFEuobY2dn2AgtiKCQgrh78NVK1JK
j0yRXgNnPpGBAgMBAAECMF0t+TBZUCi8xATSMij7VLTxv5Xi5OIXesNiXOKtYIRP
LkpYfR5PggaMScfbmqSssQIZAMwOhm9d7Y7Qi7I2j1AlYbiqdtqO54T7FQIZAONa
9dJFkC6lM3EPXR+0SZ4dqwwpiM0nvQIYYgz8thi5JK264ohq9sTvnu9yKvUN9I09
AhgfgMYZKcxtujRjkSZtMzUUNLYzzDmJe90CGDKwqcBI0v9ChaR8WHht+/chMdxj
7ez94w==
-----END RSA PRIVATE KEY-----@badkeys i didn't know anything below rsa-1024 even existed!
