Samba 4.1.22 Available for Download
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Release Notes for Samba 4.1.22
December 16, 2015
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This is a security release in order to address the following CVEs:
o CVE-2015-7540 (Remote DoS in Samba (AD) LDAP server)
o CVE-2015-3223 (Denial of service in Samba Active Directory
server)
o CVE-2015-5252 (Insufficient symlink verification in smbd)
o CVE-2015-5299 (Missing access control check in shadow copy
code)
o CVE-2015-5296 (Samba client requesting encryption vulnerable
to downgrade attack)
o CVE-2015-8467 (Denial of service attack against Windows
Active Directory server)
o CVE-2015-5330 (Remote memory read in Samba LDAP server)
Please note that if building against a system libldb, the required
version has been bumped to ldb-1.1.24. This is needed to ensure
we build against a system ldb library that contains the fixes
for CVE-2015-5330 and CVE-2015-3223.
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Details
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o CVE-2015-7540:
All versions of Samba from 4.0.0 to 4.1.21 inclusive are vulnerable to
an anonymous memory exhaustion attack in the samba daemon LDAP server.
A malicious client can send packets that cause the LDAP server provided
by the AD DC in the samba daemon process to consume unlimited memory
and be terminated.
o CVE-2015-3223:
All versions of Samba from 4.0.0 to 4.3.2 inclusive (resp. all
ldb versions up to 1.1.23 inclusive) are vulnerable to
a denial of service attack in the samba daemon LDAP server.
A malicious client can send packets that cause the LDAP server in the
samba daemon process to become unresponsive, preventing the server
from servicing any other requests.
This flaw is not exploitable beyond causing the code to loop expending
CPU resources.
o CVE-2015-5252:
All versions of Samba from 3.0.0 to 4.3.2 inclusive are vulnerable to
a bug in symlink verification, which under certain circumstances could
allow client access to files outside the exported share path.
If a Samba share is configured with a path that shares a common path
prefix with another directory on the file system, the smbd daemon may
allow the client to follow a symlink pointing to a file or directory
in that other directory, even if the share parameter "wide links" is
set to "no" (the default).
o CVE-2015-5299:
All versions of Samba from 3.2.0 to 4.3.2 inclusive are vulnerable to
a missing access control check in the vfs_shadow_copy2 module. When
looking for the shadow copy directory under the share path the current
accessing user should have DIRECTORY_LIST access rights in order to
view the current snapshots.
This was not being checked in the affected versions of Samba.
o CVE-2015-5296:
Versions of Samba from 3.2.0 to 4.3.2 inclusive do not ensure that
signing is negotiated when creating an encrypted client connection to
a server.
Without this a man-in-the-middle attack could downgrade the connection
and connect using the supplied credentials as an unsigned, unencrypted
connection.
o CVE-2015-8467:
Samba, operating as an AD DC, is sometimes operated in a domain with a
mix of Samba and Windows Active Directory Domain Controllers.
All versions of Samba from 4.0.0 to 4.3.2 inclusive, when deployed as
an AD DC in the same domain with Windows DCs, could be used to
override the protection against the MS15-096 / CVE-2015-2535 security
issue in Windows.
Prior to MS16-096 it was possible to bypass the quota of machine
accounts a non-administrative user could create. Pure Samba domains
are not impacted, as Samba does not implement the
SeMachineAccountPrivilege functionality to allow non-administrator
users to create new computer objects.
o CVE-2015-5330:
All versions of Samba from 4.0.0 to 4.3.2 inclusive (resp. all
ldb versions up to 1.1.23 inclusive) are vulnerable to
a remote memory read attack in the samba daemon LDAP server.
A malicious client can send packets that cause the LDAP server in the
samba daemon process to return heap memory beyond the length of the
requested value.
This memory may contain data that the client should not be allowed to
see, allowing compromise of the server.
The memory may either be returned to the client in an error string, or
stored in the database by a suitabily privileged user. If untrusted
users can create objects in your database, please confirm that all DN
and name attributes are reasonable.
Changes since 4.1.21:
---------------------
o Andrew Bartlett <abartlet@samba.org>
* BUG 11552: CVE-2015-8467: samdb: Match MS15-096 behaviour for
userAccountControl.
o Jeremy Allison <jra@samba.org>
* BUG 9187: CVE-2015-7540: Bogus LDAP request cause samba to use all the
memory and be ookilled.
* BUG 11325: CVE-2015-3223: Fix LDAP \00 search expression attack DoS.
* BUG 11395: CVE-2015-5252: Fix insufficient symlink verification (file
access outside the share).
* BUG 11529: CVE-2015-5299: s3-shadow-copy2: Fix missing access check on
snapdir.
o Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
* BUG 11599: CVE-2015-5330: Fix remote read memory exploit in LDB.
o Stefan Metzmacher <metze@samba.org>
* BUG 11536: CVE-2015-5296: Add man in the middle protection when forcing
smb encryption on the client side.