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Debian Security Advisory DSA-3740-1 security@debian.org
https://www.debian.org/security/ Salvatore Bonaccorso
December 19, 2016 https://www.debian.org/security/faq
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Package : samba
CVE ID : CVE-2016-2119 CVE-2016-2123 CVE-2016-2125 CVE-2016-2126
Debian Bug : 830195

Several 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.

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.

We recommend that you upgrade your samba packages.

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://www.debian.org/security/