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Ubuntu Security Notice USN-4510-2
September 17, 2020

samba vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 14.04 ESM

Summary:

Samba would allow unintended access to files over the network.

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

Details:

USN-4510-1 fixed a vulnerability in Samba. This update provides
the corresponding update for Ubuntu 14.04 ESM.

Original advisory details:

 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 14.04 ESM:
  samba                           2:4.3.11+dfsg-0ubuntu0.14.04.20+esm9

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

References:
  https://usn.ubuntu.com/4510-2
  https://usn.ubuntu.com/4510-1
  CVE-2020-1472