Debian DSA-3740-1 : samba - security update
Medium Nessus Plugin ID 95936
SynopsisThe remote Debian host is missing a security-related update.
DescriptionSeveral vulnerabilities have been discovered in Samba, a SMB/CIFS file, print, and login server for Unix. The Common Vulnerabilities and Exposures project identifies the following issues :
- CVE-2016-2119 Stefan Metzmacher discovered that client-side SMB2/3 required signing can be downgraded, allowing a man-in-the-middle attacker to impersonate a server being connected to by Samba, and return malicious results.
- CVE-2016-2123 Trend Micro's Zero Day Initiative and Frederic Besler discovered that the routine ndr_pull_dnsp_name, used to parse data from the Samba Active Directory ldb database, contains an integer overflow flaw, leading to an attacker-controlled memory overwrite. An authenticated user can take advantage of this flaw for remote privilege escalation.
- CVE-2016-2125 Simo Sorce of Red Hat discovered that the Samba client code always requests a forwardable ticket when using Kerberos authentication. A target server, which must be in the current or trusted domain/realm, is given a valid general purpose Kerberos 'Ticket Granting Ticket' (TGT), which can be used to fully impersonate the authenticated user or service.
- CVE-2016-2126 Volker Lendecke discovered several flaws in the Kerberos PAC validation. A remote, authenticated, attacker can cause the winbindd process to crash using a legitimate Kerberos ticket due to incorrect handling of the PAC checksum. A local service with access to the winbindd privileged pipe can cause winbindd to cache elevated access permissions.
SolutionUpgrade the samba packages.
For the stable distribution (jessie), these problems have been fixed in version 2:4.2.14+dfsg-0+deb8u2. In addition, this update contains several changes originally targeted for the upcoming jessie point release.