USN-3158-1: Samba vulnerabilities

Ubuntu Security Notice USN-3158-1

19th December, 2016

samba vulnerabilities

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

  • Ubuntu 16.10
  • Ubuntu 16.04 LTS
  • Ubuntu 14.04 LTS
  • Ubuntu 12.04 LTS

Summary

Several security issues were fixed in Samba.

Software description

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

Details

Frederic Besler and others discovered that the ndr_pull_dnsp_nam
function in Samba contained an integer overflow. An authenticated
attacker could use this to gain administrative privileges. This issue
only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, and Ubuntu 16.10.
(CVE-2016-2123)

Simo Sorce discovered that that Samba clients always requested
a forwardable ticket when using Kerberos authentication. An
attacker could use this to impersonate an authenticated user or
service. (CVE-2016-2125)

Volker Lendecke discovered that Kerberos PAC validation implementation
in Samba contained multiple vulnerabilities. An authenticated attacker
could use this to cause a denial of service or gain administrative
privileges. This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04
LTS, and Ubuntu 16.10. (CVE-2016-2126)

Update instructions

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

Ubuntu 16.10:
libsmbclient 2:4.4.5+dfsg-2ubuntu5.2
winbind 2:4.4.5+dfsg-2ubuntu5.2
samba 2:4.4.5+dfsg-2ubuntu5.2
Ubuntu 16.04 LTS:
libsmbclient 2:4.3.11+dfsg-0ubuntu0.16.04.3
winbind 2:4.3.11+dfsg-0ubuntu0.16.04.3
samba 2:4.3.11+dfsg-0ubuntu0.16.04.3
Ubuntu 14.04 LTS:
libsmbclient 2:4.3.11+dfsg-0ubuntu0.14.04.4
winbind 2:4.3.11+dfsg-0ubuntu0.14.04.4
samba 2:4.3.11+dfsg-0ubuntu0.14.04.4
Ubuntu 12.04 LTS:
libsmbclient 2:3.6.25-0ubuntu0.12.04.5
samba 2:3.6.25-0ubuntu0.12.04.5

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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

References

CVE-2016-2123, CVE-2016-2125, CVE-2016-2126