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Ubuntu 21.10 USN-5142-3 Security Advisory: Samba Kerberos Regression

ubuntu
Calendar Grey December 13, 2021
Dist Ubuntu Esm H88
A recent Ubuntu update addresses a Samba issue affecting Kerberos authentication, thereby bolstering security measures in specific settings.
USN-5142-1 introduced a regression in Samba.

Summary

USN-5142-1 introduced a regression in Samba.

Software Description:

- samba: SMB/CIFS file, print, and login server for Unix

Details:

USN-5142-1 fixed vulnerabilities in Samba. Some of the upstream changes

introduced a regression in Kerberos authentication in certain environments.

Please see the following upstream bug for more information:

This update fixes the problem.

Original advisory details:

Stefan Metzmacher discovered that Samba incorrectly handled SMB1 client

connections. A remote attacker could possibly use this issue to downgrade

connections to plaintext authentication. (CVE-2016-2124)

Andrew Bartlett discovered that Samba incorrectly mapping domain users to

local users. An authenticated attacker could possibly use this issue to

become root on domain members. (CVE-2020-25717)

Andrew Bartlett discovered that Samba did not correctly sandbox Kerberos

tickets issues by an RODC. An RODC could print administrator tickets,

contrary to ...

Read the Full Advisory

Topics%20covered

Topics Covered

security advisory security issue samba kerberos authentication ubuntu regression

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 21.10:
  samba                           2:4.13.14+dfsg-0ubuntu0.21.10.4

Ubuntu 21.04:
  samba                           2:4.13.14+dfsg-0ubuntu0.21.04.4

Ubuntu 20.04 LTS:
  samba                           2:4.13.14+dfsg-0ubuntu0.20.04.4

In general, a standard system update will make all the necessary changes.

References

https://ubuntu.com/security/notices/USN-5142-3

https://ubuntu.com/security/notices/USN-5142-1

https://bugs.launchpad.net/ubuntu/+source/samba/+bug/1950363

Severity
critical
Lowest
Low
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Critical

December 13, 2021

Topics%20covered

Topics Covered

security advisory security issue samba kerberos authentication ubuntu regression

Package Information

https://launchpad.net/ubuntu/+source/samba/2:4.13.14+dfsg-0ubuntu0.21.10.4
https://launchpad.net/ubuntu/+source/samba/2:4.13.14+dfsg-0ubuntu0.21.04.4
https://launchpad.net/ubuntu/+source/samba/2:4.13.14+dfsg-0ubuntu0.20.04.4

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