(RHSA-2016:0623) Important: samba security update

Samba is an open-source implementation of the Server Message Block (SMB)
protocol and the related Common Internet File System (CIFS) protocol, which
allow PC-compatible machines to share files, printers, and various information.

Security Fix(es):

• A protocol flaw, publicly referred to as Badlock, was found in the Security
  Account Manager Remote Protocol (MS-SAMR) and the Local Security Authority
  (Domain Policy) Remote Protocol (MS-LSAD). Any authenticated DCE/RPC connection
  that a client initiates against a server could be used by a man-in-the-middle
  attacker to impersonate the authenticated user against the SAMR or LSA service
  on the server. As a result, the attacker would be able to get read/write access
  to the Security Account Manager database, and use this to reveal all passwords
  or any other potentially sensitive information in that database. (CVE-2016-2118)

• Several flaws were found in Samba’s implementation of NTLMSSP authentication.
  An unauthenticated, man-in-the-middle attacker could use this flaw to clear the
  encryption and integrity flags of a connection, causing data to be transmitted
  in plain text. The attacker could also force the client or server into sending
  data in plain text even if encryption was explicitly requested for that
  connection. (CVE-2016-2110)

• It was discovered that Samba configured as a Domain Controller would establish
  a secure communication channel with a machine using a spoofed computer name. A
  remote attacker able to observe network traffic could use this flaw to obtain
  session-related information about the spoofed machine. (CVE-2016-2111)

Red Hat would like to thank the Samba project for reporting these issues.
Upstream acknowledges Stefan Metzmacher (SerNet) as the original reporter of
CVE-2016-2118 and CVE-2016-2110.