CentOS 5 : samba (CESA-2016:0621) (Badlock)
Medium Nessus Plugin ID 90452
SynopsisThe remote CentOS host is missing one or more security updates.
DescriptionAn update for samba is now available for Red Hat Enterprise Linux 5.
Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.
[Updated 14 April 2016] This advisory previously incorrectly listed the CVE-2016-2112 issue as addressed by this update. However, this issue did not affect the samba packages on Red Hat Enterprise Linux 5.
The CVE-2016-2115 was also incorrectly listed as addressed by this update. This issue does affect the samba packages on Red Hat Enterprise Linux 5. Customers are advised to use the 'client signing = required' configuration option in the smb.conf file to mitigate CVE-2016-2115. No changes have been made to the packages.
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.
* 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.
SolutionUpdate the affected samba packages.