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USN-5174-1: Samba vulnerabilities

6 December 2021

Several security issues were fixed in Samba.

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Releases

Packages

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

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 properly check sensitive
attributes. An authenticated attacker could possibly use this issue to
escalate privileges. (CVE-2020-25722)

Joseph Sutton discovered that Samba incorrectly handled certain TGS
requests. An authenticated attacker could possibly use this issue to cause
Samba to crash, resulting in a denial of service. (CVE-2021-3671)

The fix for CVE-2020-25717 results in possible behaviour changes that could
affect certain environments. Please see the upstream advisory for more
information:

https://www.samba.org/samba/security/CVE-2020-25717.html

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Update instructions

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

Ubuntu 18.04

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

References

Related notices

  • USN-5142-1: ctdb, libpam-winbind, samba, samba-common-bin, samba-dev, smbclient, registry-tools, libsmbclient, python3-samba, winbind, libnss-winbind, samba-dsdb-modules, libwbclient-dev, samba-libs, samba-common, samba-testsuite, libwbclient0, samba-vfs-modules, libsmbclient-dev
  • USN-5675-1: heimdal-clients, heimdal-kcm, heimdal-docs, heimdal-servers-x, heimdal-servers, libkafs0-heimdal, libhcrypto4-heimdal, libroken18-heimdal, libhdb9-heimdal, libkadm5srv8-heimdal, heimdal, libasn1-8-heimdal, libotp0-heimdal, libkrb5-26-heimdal, libgssapi3-heimdal, heimdal-kdc, heimdal-multidev, heimdal-clients-x, libheimbase1-heimdal, libkadm5clnt7-heimdal, libsl0-heimdal, heimdal-dev, libwind0-heimdal, libheimntlm0-heimdal, libhx509-5-heimdal, libkdc2-heimdal

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Further reading