USN-2855-2: Samba regression

16 February 2016

samba regression

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

  • Ubuntu 15.10
  • Ubuntu 14.04 LTS
  • Ubuntu 12.04 LTS

Summary

USN-2855-1 introduced a regression in Samba.

Software Description

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

Details

USN-2855-1 fixed vulnerabilities in Samba. The upstream fix for CVE-2015-5252 introduced a regression in certain specific environments. This update fixes the problem.

Original advisory details:

Thilo Uttendorfer discovered that the Samba LDAP server incorrectly handled certain packets. A remote attacker could use this issue to cause the LDAP server to stop responding, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS, Ubuntu 15.04 and Ubuntu 15.10. (CVE-2015-3223)

Jan Kasprzak discovered that Samba incorrectly handled certain symlinks. A remote attacker could use this issue to access files outside the exported share path. (CVE-2015-5252)

Stefan Metzmacher discovered that Samba did not enforce signing when creating encrypted connections. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to view sensitive information. (CVE-2015-5296)

It was discovered that Samba incorrectly performed access control when using the VFS shadow_copy2 module. A remote attacker could use this issue to access snapshots, contrary to intended permissions. (CVE-2015-5299)

Douglas Bagnall discovered that Samba incorrectly handled certain string lengths. A remote attacker could use this issue to possibly access sensitive information. (CVE-2015-5330)

It was discovered that the Samba LDAP server incorrectly handled certain packets. A remote attacker could use this issue to cause the LDAP server to stop responding, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS, Ubuntu 15.04 and Ubuntu 15.10. (CVE-2015-7540)

Andrew Bartlett discovered that Samba incorrectly checked administrative privileges during creation of machine accounts. A remote attacker could possibly use this issue to bypass intended access restrictions in certain environments. This issue only affected Ubuntu 14.04 LTS, Ubuntu 15.04 and Ubuntu 15.10. (CVE-2015-8467)

Update instructions

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

Ubuntu 15.10
samba - 2:4.1.17+dfsg-4ubuntu3.2
Ubuntu 14.04 LTS
samba - 2:4.1.6+dfsg-1ubuntu2.14.04.12
Ubuntu 12.04 LTS
samba - 2:3.6.3-2ubuntu2.14

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