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

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

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  • tanja@mastodon.catgirl.cloudT tanja@mastodon.catgirl.cloud

    @badkeys@infosec.exchange oooofffff

    But why would they turn down the bug bounty????

    <img class="not-responsive emoji" src="https://content.mastodon.catgirl.cloud/custom_emojis/images/000/055/198/original/neocat_googly_shocked.png" title=":neocat_googly_shocked:" />

    oscherler@tooting.chO This user is from outside of this forum
    oscherler@tooting.chO This user is from outside of this forum
    oscherler@tooting.ch
    wrote last edited by
    #33

    @tanja Because they’re cheap assholes? Just a wild guess.

    m_berberich@chaos.socialM 1 Reply Last reply
    0
    • keksdosenmann@mastodon.socialK keksdosenmann@mastodon.social

      @badkeys Telekom. Die machen das.

      christianrickert@23.socialC This user is from outside of this forum
      christianrickert@23.socialC This user is from outside of this forum
      christianrickert@23.social
      wrote last edited by
      #34

      @keksdosenmann @badkeys

      Die schaffen uns. 😮‍💨

      1 Reply Last reply
      1
      0
      • lunareclipse@snug.moeL lunareclipse@snug.moe

        @badkeys bad companies that don't pay out bug bounties can have uncoordinated public disclosure as a treat :3

        kbruen@procial.tchncs.deK This user is from outside of this forum
        kbruen@procial.tchncs.deK This user is from outside of this forum
        kbruen@procial.tchncs.de
        wrote last edited by
        #35

        @lunareclipse@snug.moe @badkeys@infosec.exchange I mean, if it's out of scope, then it's not even a disclosure, as "out of scope" is an admittance that it's no biggie for the information to be public to begin with, right?

        1 Reply Last reply
        0
        • badkeys@infosec.exchangeB badkeys@infosec.exchange

          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-----

          robot@wetdry.worldR This user is from outside of this forum
          robot@wetdry.worldR This user is from outside of this forum
          robot@wetdry.world
          wrote last edited by
          #36

          @badkeys ReallySecureAlgorithm

          1 Reply Last reply
          0
          • badkeys@infosec.exchangeB badkeys@infosec.exchange

            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-----

            diziet@mastodon.me.ukD This user is from outside of this forum
            diziet@mastodon.me.ukD This user is from outside of this forum
            diziet@mastodon.me.uk
            wrote last edited by
            #37

            @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

            badrihippo@fosstodon.orgB 1 Reply Last reply
            0
            • R relay@relay.infosec.exchange shared this topic
            • badkeys@infosec.exchangeB badkeys@infosec.exchange

              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-----

              selea@social.linux.pizzaS This user is from outside of this forum
              selea@social.linux.pizzaS This user is from outside of this forum
              selea@social.linux.pizza
              wrote last edited by
              #38

              @badkeys

              What wat. they published the private key?!

              kramse@helvede.netK 1 Reply Last reply
              0
              • badkeys@infosec.exchangeB badkeys@infosec.exchange

                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-----

                artlog@agora.l0g.euA This user is from outside of this forum
                artlog@agora.l0g.euA This user is from outside of this forum
                artlog@agora.l0g.eu
                wrote last edited by
                #39
                @badkeys

                I don't remember have ever seen lower RSA keys size than 512 bits... We have a winner here !
                1 Reply Last reply
                0
                • momo@social.linux.pizzaM momo@social.linux.pizza

                  @badkeys
                  Do they accept mails from noncommercial mailservers at their nl branch or do they refuse them with "554 None/Bad Reputation" as the german branch does, unless the mail admin publishes full personal (!) contact infos on a webserver hosted on the smtp machine? Just asking, because THOSE guys behave like they wrote the SMTP RFCs all by themselves...

                  bekopharm@indieweb.socialB This user is from outside of this forum
                  bekopharm@indieweb.socialB This user is from outside of this forum
                  bekopharm@indieweb.social
                  wrote last edited by
                  #40

                  @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

                  momo@social.linux.pizzaM 1 Reply Last reply
                  0
                  • selea@social.linux.pizzaS selea@social.linux.pizza

                    @badkeys

                    What wat. they published the private key?!

                    kramse@helvede.netK This user is from outside of this forum
                    kramse@helvede.netK This user is from outside of this forum
                    kramse@helvede.net
                    wrote last edited by
                    #41

                    @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

                    1 Reply Last reply
                    0
                    • buherator@infosec.placeB buherator@infosec.place
                      @mcr314 @badkeys Source? I doubt someone who makes a mistake like this knows what ECDSA is.
                      J This user is from outside of this forum
                      J This user is from outside of this forum
                      janet_catcus@hachyderm.io
                      wrote last edited by
                      #42

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

                      1 Reply Last reply
                      0
                      • diziet@mastodon.me.ukD 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

                        badrihippo@fosstodon.orgB This user is from outside of this forum
                        badrihippo@fosstodon.orgB This user is from outside of this forum
                        badrihippo@fosstodon.org
                        wrote last edited by
                        #43

                        @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

                        diziet@mastodon.me.ukD 1 Reply Last reply
                        0
                        • badkeys@infosec.exchangeB badkeys@infosec.exchange

                          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-----

                          linear@nya.socialL This user is from outside of this forum
                          linear@nya.socialL This user is from outside of this forum
                          linear@nya.social
                          wrote last edited by
                          #44
                          @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.socialL 1 Reply Last reply
                          0
                          • linear@nya.socialL 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.socialL This user is from outside of this forum
                            linear@nya.socialL This user is from outside of this forum
                            linear@nya.social
                            wrote last edited by
                            #45
                            @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
                            1 Reply Last reply
                            0
                            • bekopharm@indieweb.socialB 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

                              momo@social.linux.pizzaM This user is from outside of this forum
                              momo@social.linux.pizzaM This user is from outside of this forum
                              momo@social.linux.pizza
                              wrote last edited by
                              #46

                              @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.

                              j_r@social.jugendhacker.deJ 1 Reply Last reply
                              0
                              • oscherler@tooting.chO oscherler@tooting.ch

                                @tanja Because they’re cheap assholes? Just a wild guess.

                                m_berberich@chaos.socialM This user is from outside of this forum
                                m_berberich@chaos.socialM This user is from outside of this forum
                                m_berberich@chaos.social
                                wrote last edited by
                                #47

                                @oscherler @tanja

                                Or they did not understand the problem?

                                1 Reply Last reply
                                0
                                • lunareclipse@snug.moeL lunareclipse@snug.moe

                                  @badkeys bad companies that don't pay out bug bounties can have uncoordinated public disclosure as a treat :3

                                  yama@tech.lgbtY This user is from outside of this forum
                                  yama@tech.lgbtY This user is from outside of this forum
                                  yama@tech.lgbt
                                  wrote last edited by
                                  #48

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

                                  1 Reply Last reply
                                  0
                                  • badkeys@infosec.exchangeB badkeys@infosec.exchange

                                    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-----

                                    yama@tech.lgbtY This user is from outside of this forum
                                    yama@tech.lgbtY This user is from outside of this forum
                                    yama@tech.lgbt
                                    wrote last edited by
                                    #49

                                    @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...

                                    varx@infosec.exchangeV 1 Reply Last reply
                                    0
                                    • badrihippo@fosstodon.orgB 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

                                      diziet@mastodon.me.ukD This user is from outside of this forum
                                      diziet@mastodon.me.ukD This user is from outside of this forum
                                      diziet@mastodon.me.uk
                                      wrote last edited by
                                      #50

                                      @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

                                      1 Reply Last reply
                                      0
                                      • badkeys@infosec.exchangeB badkeys@infosec.exchange

                                        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-----

                                        x0r@mamot.frX This user is from outside of this forum
                                        x0r@mamot.frX This user is from outside of this forum
                                        x0r@mamot.fr
                                        wrote last edited by
                                        #51

                                        @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

                                        1 Reply Last reply
                                        0
                                        • badkeys@infosec.exchangeB badkeys@infosec.exchange

                                          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-----

                                          woffs@fe.disroot.orgW This user is from outside of this forum
                                          woffs@fe.disroot.orgW This user is from outside of this forum
                                          woffs@fe.disroot.org
                                          wrote last edited by
                                          #52
                                          @badkeys hot take: dkim does not matter anyway
                                          1 Reply Last reply
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