Ubuntu: USN-2950-4: Samba regressions

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.