Debian Security Advisory DSA-3740-1 email@example.com https://www.debian.org/security/ Salvatore Bonaccorso December 19, 2016 https://www.debian.org/security/faq
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:
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.
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.
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.
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/
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