Ubuntu Security Notice 3976-3 - USN-3976-1 fixed a vulnerability in Samba. The update introduced a regression causing Samba to occasionally crash. This update fixes the problem. Isaac Boukris and Andrew Bartlett discovered that Samba incorrectly checked S4U2Self packets. In certain environments, a remote attacker could possibly use this issue to escalate privileges. Various other issues were also addressed.
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Ubuntu Security Notice USN-3976-3
May 27, 2019
samba regression
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A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
Summary:
USN-3976-1 introduced a regression in Samba.
Software Description:
- samba: SMB/CIFS file, print, and login server for Unix
Details:
USN-3976-1 fixed a vulnerability in Samba. The update introduced a
regression causing Samba to occasionally crash. This update fixes the
problem.
We apologize for the inconvenience.
Original advisory details:
Isaac Boukris and Andrew Bartlett discovered that Samba incorrectly checked
S4U2Self packets. In certain environments, a remote attacker could possibly
use this issue to escalate privileges.
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 18.04 LTS:
samba 2:4.7.6+dfsg~ubuntu-0ubuntu2.11
Ubuntu 16.04 LTS:
samba 2:4.3.11+dfsg-0ubuntu0.16.04.21
In general, a standard system update will make all the necessary changes.
References:
https://usn.ubuntu.com/usn/usn-3976-3
https://usn.ubuntu.com/usn/usn-3976-1
https://launchpad.net/bugs/1827924
Package Information:
https://launchpad.net/ubuntu/+source/samba/2:4.7.6+dfsg~ubuntu-0ubuntu2.11
https://launchpad.net/ubuntu/+source/samba/2:4.3.11+dfsg-0ubuntu0.16.04.21