USN-2950-4: Samba regressions

Ubuntu Security Notice USN-2950-4

18th May, 2016

samba regressions

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

• Ubuntu 12.04 LTS

Summary

USN-2950-1 introduced regressions in Samba.

Software description

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

Details

USN-2950-1 fixed vulnerabilities in Samba. The backported fixes introduced
in Ubuntu 12.04 LTS caused interoperability issues. This update fixes
compatibility with certain NAS devices, and allows connecting to Samba 3.6
servers by relaxing the "client ipc signing" parameter to "auto".

We apologize for the inconvenience.

Original advisory details:

Jouni Knuutinen discovered that Samba contained multiple flaws in the
DCE/RPC implementation. A remote attacker could use this issue to perform
a denial of service, downgrade secure connections by performing a man in
the middle attack, or possibly execute arbitrary code. (CVE-2015-5370)

Stefan Metzmacher discovered that Samba contained multiple flaws in the
NTLMSSP authentication implementation. A remote attacker could use this
issue to downgrade connections to plain text by performing a man in the
middle attack. (CVE-2016-2110)

Alberto Solino discovered that a Samba domain controller would establish a
secure connection to a server with a spoofed computer name. A remote
attacker could use this issue to obtain sensitive information.
(CVE-2016-2111)

Stefan Metzmacher discovered that the Samba LDAP implementation did not
enforce integrity protection. A remote attacker could use this issue to
hijack LDAP connections by performing a man in the middle attack.
(CVE-2016-2112)

Stefan Metzmacher discovered that Samba did not validate TLS certificates.
A remote attacker could use this issue to spoof a Samba server.
(CVE-2016-2113)

Stefan Metzmacher discovered that Samba did not enforce SMB signing even if
configured to. A remote attacker could use this issue to perform a man in
the middle attack. (CVE-2016-2114)

Stefan Metzmacher discovered that Samba did not enable integrity protection
for IPC traffic. A remote attacker could use this issue to perform a man in
the middle attack. (CVE-2016-2115)

Stefan Metzmacher discovered that Samba incorrectly handled the MS-SAMR and
MS-LSAD protocols. A remote attacker could use this flaw with a man in the
middle attack to impersonate users and obtain sensitive information from
the Security Account Manager database. This flaw is known as Badlock.
(CVE-2016-2118)

Samba has been updated to 4.3.8 in Ubuntu 14.04 LTS and Ubuntu 15.10.
Ubuntu 12.04 LTS has been updated to 3.6.25 with backported security fixes.

In addition to security fixes, the updated packages contain bug fixes,
new features, and possibly incompatible changes. Configuration changes may
be required in certain environments.

Update instructions

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

Ubuntu 12.04 LTS:

samba 2:3.6.25-0ubuntu0.12.04.4

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

LP: 1574403, LP: 1576109