Samba Badlock Vulnerability
Medium Nessus Plugin ID 90509
SynopsisAn SMB server running on the remote host is affected by the Badlock vulnerability.
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.