** Description changed: + [ Impact ] + + The default crypto algorithm suite selected for the master key in the + ubuntu krb5-kdc package is 3des-sha1. This comes from a config file + shipped with the packaging which overrides upstream's default choice. + + Users who deploy a KDC using this package will be using an algorithm + deprecated since many years ago, and considered broken nowadays for + security applications. + + This update removes the specification of an algorithm and leaves it to + the upstream default, which is aes256-cts-hmac-sha1-96[1]. + + Kerberos is quite conservative when it comes to updating encryption + algorithms, and one could argue that the default should be something + like aes256-cts-hmac-sha384-192, but in this SRU we are sticking the + upstream default (by not specifying any value). This is also what debian + is doing, and what we have in kinetic and later. + + 1. https://manpages.ubuntu.com/manpages/jammy/man5/kdc.conf.5.html + search for "master_key_type" + + + [ Test Plan ] + + * detailed instructions how to reproduce the bug + + * these should allow someone who is not familiar with the affected + package to reproduce the bug and verify that the updated package fixes + the problem. + + * if other testing is appropriate to perform before landing this update, + this should also be described here. + + [ Where problems could occur ] + + * Think about what the upload changes in the software. Imagine the change is + wrong or breaks something else: how would this show up? + + * It is assumed that any SRU candidate patch is well-tested before + upload and has a low overall risk of regression, but it's important + to make the effort to think about what ''could'' happen in the + event of a regression. + + * This must '''never''' be "None" or "Low", or entirely an argument as to why + your upload is low risk. + + * This both shows the SRU team that the risks have been considered, + and provides guidance to testers in regression-testing the SRU. + + [ Other Info ] + + * Anything else you think is useful to include + * Anticipate questions from users, SRU, +1 maintenance, security teams and the Technical Board + * and address these questions in advance + + Default setting in /etc/krb5kdc/kdc.conf, as installed from krb5-kdc in Ubuntu 22.04 Server: master_key_type = des3-hmac-sha1 3DES was deprecated by NIST in 2017, i.e. give years ago! Reference: https://csrc.nist.gov/News/2017/Update-to-Current-Use-and-Deprecation- of-TDEA . This should not be a default since a very long time, and particularly not for new installations. If a compatibility with out-of- date installations is necessary, this should be explicitly made be the administrator. SHA-1 was deprecated as well, in 2011, i.e. eleven years ago! Reference: https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-131a.pdf . A reasonable default would probably be: master_key_type = aes256-cts-hmac-sha384-192 ProblemType: Bug DistroRelease: Ubuntu 22.04 Package: krb5-kdc 1.19.2-2 ProcVersionSignature: Ubuntu 5.15.0-40.43-generic 5.15.35 Uname: Linux 5.15.0-40-generic x86_64 ApportVersion: 2.20.11-0ubuntu82.1 Architecture: amd64 CasperMD5CheckResult: pass Date: Thu Jul 14 12:34:22 2022 InstallationDate: Installed on 2022-05-30 (45 days ago) InstallationMedia: Ubuntu-Server 22.04 LTS "Jammy Jellyfish" - Release amd64 (20220421) ProcEnviron: - TERM=xterm-256color - PATH=(custom, no user) - XDG_RUNTIME_DIR=<set> - LANG=en_IE.UTF-8 - SHELL=/bin/bash + TERM=xterm-256color + PATH=(custom, no user) + XDG_RUNTIME_DIR=<set> + LANG=en_IE.UTF-8 + SHELL=/bin/bash SourcePackage: krb5 UpgradeStatus: No upgrade log present (probably fresh install)
** Description changed: [ Impact ] The default crypto algorithm suite selected for the master key in the - ubuntu krb5-kdc package is 3des-sha1. This comes from a config file + ubuntu krb5-kdc package is des3-hmac-sha1. This comes from a config file shipped with the packaging which overrides upstream's default choice. Users who deploy a KDC using this package will be using an algorithm deprecated since many years ago, and considered broken nowadays for security applications. This update removes the specification of an algorithm and leaves it to the upstream default, which is aes256-cts-hmac-sha1-96[1]. Kerberos is quite conservative when it comes to updating encryption algorithms, and one could argue that the default should be something like aes256-cts-hmac-sha384-192, but in this SRU we are sticking the upstream default (by not specifying any value). This is also what debian is doing, and what we have in kinetic and later. 1. https://manpages.ubuntu.com/manpages/jammy/man5/kdc.conf.5.html search for "master_key_type" - [ Test Plan ] - * detailed instructions how to reproduce the bug + * detailed instructions how to reproduce the bug - * these should allow someone who is not familiar with the affected - package to reproduce the bug and verify that the updated package fixes - the problem. + * these should allow someone who is not familiar with the affected + package to reproduce the bug and verify that the updated package fixes + the problem. - * if other testing is appropriate to perform before landing this update, - this should also be described here. + * if other testing is appropriate to perform before landing this update, + this should also be described here. [ Where problems could occur ] - * Think about what the upload changes in the software. Imagine the change is - wrong or breaks something else: how would this show up? + * Think about what the upload changes in the software. Imagine the change is + wrong or breaks something else: how would this show up? - * It is assumed that any SRU candidate patch is well-tested before - upload and has a low overall risk of regression, but it's important - to make the effort to think about what ''could'' happen in the - event of a regression. + * It is assumed that any SRU candidate patch is well-tested before + upload and has a low overall risk of regression, but it's important + to make the effort to think about what ''could'' happen in the + event of a regression. - * This must '''never''' be "None" or "Low", or entirely an argument as to why - your upload is low risk. + * This must '''never''' be "None" or "Low", or entirely an argument as to why + your upload is low risk. - * This both shows the SRU team that the risks have been considered, - and provides guidance to testers in regression-testing the SRU. + * This both shows the SRU team that the risks have been considered, + and provides guidance to testers in regression-testing the SRU. [ Other Info ] - - * Anything else you think is useful to include - * Anticipate questions from users, SRU, +1 maintenance, security teams and the Technical Board - * and address these questions in advance + * Anything else you think is useful to include + * Anticipate questions from users, SRU, +1 maintenance, security teams and the Technical Board + * and address these questions in advance Default setting in /etc/krb5kdc/kdc.conf, as installed from krb5-kdc in Ubuntu 22.04 Server: master_key_type = des3-hmac-sha1 3DES was deprecated by NIST in 2017, i.e. give years ago! Reference: https://csrc.nist.gov/News/2017/Update-to-Current-Use-and-Deprecation- of-TDEA . This should not be a default since a very long time, and particularly not for new installations. If a compatibility with out-of- date installations is necessary, this should be explicitly made be the administrator. SHA-1 was deprecated as well, in 2011, i.e. eleven years ago! Reference: https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-131a.pdf . A reasonable default would probably be: master_key_type = aes256-cts-hmac-sha384-192 ProblemType: Bug DistroRelease: Ubuntu 22.04 Package: krb5-kdc 1.19.2-2 ProcVersionSignature: Ubuntu 5.15.0-40.43-generic 5.15.35 Uname: Linux 5.15.0-40-generic x86_64 ApportVersion: 2.20.11-0ubuntu82.1 Architecture: amd64 CasperMD5CheckResult: pass Date: Thu Jul 14 12:34:22 2022 InstallationDate: Installed on 2022-05-30 (45 days ago) InstallationMedia: Ubuntu-Server 22.04 LTS "Jammy Jellyfish" - Release amd64 (20220421) ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_IE.UTF-8 SHELL=/bin/bash SourcePackage: krb5 UpgradeStatus: No upgrade log present (probably fresh install) -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to krb5 in Ubuntu. https://bugs.launchpad.net/bugs/1981697 Title: KDC: weak crypto in default settings Status in krb5 package in Ubuntu: Fix Released Status in krb5 source package in Jammy: In Progress Status in krb5 source package in Kinetic: Fix Released Status in krb5 package in Debian: Fix Released Bug description: [ Impact ] The default crypto algorithm suite selected for the master key in the ubuntu krb5-kdc package is des3-hmac-sha1. This comes from a config file shipped with the packaging which overrides upstream's default choice. Users who deploy a KDC using this package will be using an algorithm deprecated since many years ago, and considered broken nowadays for security applications. This update removes the specification of an algorithm and leaves it to the upstream default, which is aes256-cts-hmac-sha1-96[1]. Kerberos is quite conservative when it comes to updating encryption algorithms, and one could argue that the default should be something like aes256-cts-hmac-sha384-192, but in this SRU we are sticking the upstream default (by not specifying any value). This is also what debian is doing, and what we have in kinetic and later. 1. https://manpages.ubuntu.com/manpages/jammy/man5/kdc.conf.5.html search for "master_key_type" [ Test Plan ] * detailed instructions how to reproduce the bug * these should allow someone who is not familiar with the affected package to reproduce the bug and verify that the updated package fixes the problem. * if other testing is appropriate to perform before landing this update, this should also be described here. [ Where problems could occur ] * Think about what the upload changes in the software. Imagine the change is wrong or breaks something else: how would this show up? * It is assumed that any SRU candidate patch is well-tested before upload and has a low overall risk of regression, but it's important to make the effort to think about what ''could'' happen in the event of a regression. * This must '''never''' be "None" or "Low", or entirely an argument as to why your upload is low risk. * This both shows the SRU team that the risks have been considered, and provides guidance to testers in regression-testing the SRU. [ Other Info ] * Anything else you think is useful to include * Anticipate questions from users, SRU, +1 maintenance, security teams and the Technical Board * and address these questions in advance Default setting in /etc/krb5kdc/kdc.conf, as installed from krb5-kdc in Ubuntu 22.04 Server: master_key_type = des3-hmac-sha1 3DES was deprecated by NIST in 2017, i.e. give years ago! Reference: https://csrc.nist.gov/News/2017/Update-to-Current-Use-and-Deprecation- of-TDEA . This should not be a default since a very long time, and particularly not for new installations. If a compatibility with out- of-date installations is necessary, this should be explicitly made be the administrator. SHA-1 was deprecated as well, in 2011, i.e. eleven years ago! Reference: https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-131a.pdf . A reasonable default would probably be: master_key_type = aes256-cts-hmac-sha384-192 ProblemType: Bug DistroRelease: Ubuntu 22.04 Package: krb5-kdc 1.19.2-2 ProcVersionSignature: Ubuntu 5.15.0-40.43-generic 5.15.35 Uname: Linux 5.15.0-40-generic x86_64 ApportVersion: 2.20.11-0ubuntu82.1 Architecture: amd64 CasperMD5CheckResult: pass Date: Thu Jul 14 12:34:22 2022 InstallationDate: Installed on 2022-05-30 (45 days ago) InstallationMedia: Ubuntu-Server 22.04 LTS "Jammy Jellyfish" - Release amd64 (20220421) ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_IE.UTF-8 SHELL=/bin/bash SourcePackage: krb5 UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/krb5/+bug/1981697/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
