Samba Badlock Vulnerability
Medium Nessus Plugin ID 90509
SynopsisAn SMB server running on the remote host is affected by the Badlock
DescriptionThe version of Samba, a CIFS/SMB server for Linux and Unix, running on
the remote host is affected by a flaw, known as Badlock, that exists
in the Security Account Manager (SAM) and Local Security
Authority (Domain Policy) (LSAD) protocols due to improper
authentication level negotiation over Remote Procedure Call (RPC)
channels. A man-in-the-middle attacker who is able to able to
intercept the traffic between a client and a server hosting a SAM
database can exploit this flaw to force a downgrade of the
authentication level, which allows the execution of arbitrary Samba
network calls in the context of the intercepted user, such as viewing
or modifying sensitive security data in the Active Directory (AD)
database or disabling critical services.
SolutionUpgrade to Samba version 4.2.11 / 4.3.8 / 4.4.2 or later.