Your submission was sent successfully! Close

USN-4510-1: Samba vulnerability

17 September 2020

Samba would allow unintended access to files over the network.



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


Tom Tervoort discovered that the Netlogon protocol implemented by Samba
incorrectly handled the authentication scheme. A remote attacker could use
this issue to forge an authentication token and steal the credentials of
the domain admin.

This update fixes the issue by changing the "server schannel" setting to
default to "yes", instead of "auto", which will force a secure netlogon
channel. This may result in compatibility issues with older devices. A
future update may allow a finer-grained control over this setting.

Update instructions

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

Ubuntu 18.04
Ubuntu 16.04

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


Related notices

  • USN-4510-2: python-samba, libnss-winbind, libpam-winbind, smbclient, samba-testsuite, winbind, libwbclient-dev, libparse-pidl-perl, libpam-smbpass, samba-dsdb-modules, samba-doc, samba-libs, samba-vfs-modules, libsmbclient-dev, libsmbsharemodes-dev, samba, samba-common, registry-tools, samba-dev, libsmbsharemodes0, samba-common-bin, libwbclient0, libsmbclient
  • USN-4559-1: python-samba, libnss-winbind, libpam-winbind, smbclient, samba-testsuite, winbind, ctdb, libwbclient-dev, libparse-pidl-perl, samba-dsdb-modules, samba-libs, python3-samba, samba-vfs-modules, libsmbclient-dev, samba, samba-common, registry-tools, samba-dev, samba-common-bin, libwbclient0, libsmbclient