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5 <title>Samba 4.3.11 - Release Notes</title>
8 <H2>Samba 4.3.11 Available for Download</H2>
10 <a href="https://download.samba.org/pub/samba/stable/samba-4.3.11.tar.gz">Samba 4.3.11 (gzipped)</a><br>
11 <a href="https://download.samba.org/pub/samba/stable/samba-4.3.11.tar.asc">Signature</a>
14 <a href="https://download.samba.org/pub/samba/patches/samba-4.3.10-4.3.11.diffs.gz">Patch (gzipped) against Samba 4.3.10</a><br>
15 <a href="https://download.samba.org/pub/samba/patches/samba-4.3.10-4.3.11.diffs.asc">Signature</a>
19 ==============================
20 Release Notes for Samba 4.3.11
22 ==============================
25 This is a security release in order to address the following defect:
27 o CVE-2016-2119 (Client side SMB2/3 required signing can be downgraded)
34 It's possible for an attacker to downgrade the required signing for
35 an SMB2/3 client connection, by injecting the SMB2_SESSION_FLAG_IS_GUEST
36 or SMB2_SESSION_FLAG_IS_NULL flags.
38 This means that the attacker can impersonate a server being connected to by
39 Samba, and return malicious results.
41 The primary concern is with winbindd, as it uses DCERPC over SMB2 when talking
42 to domain controllers as a member server, and trusted domains as a domain
43 controller. These DCE/RPC connections were intended to protected by the
44 combination of "client ipc signing" and
45 "client ipc max protocol" in their effective default settings
46 ("mandatory" and "SMB3_11").
48 Additionally, management tools like net, samba-tool and rpcclient use DCERPC
49 over SMB2/3 connections.
51 By default, other tools in Samba are unprotected, but rarely they are
52 configured to use smb signing, via the "client signing" parameter (the default
53 is "if_required"). Even more rarely the "client max protocol" is set to SMB2,
54 rather than the NT1 default.
56 If both these conditions are met, then this issue would also apply to these
57 other tools, including command line tools like smbcacls, smbcquota, smbclient,
58 smbget and applications using libsmbclient.
64 o Stefan Metzmacher <metze@samba.org>
65 * BUG 11860: CVE-2016-2119: Fix client side SMB2 signing downgrade.
66 * BUG 11948: Total dcerpc response payload more than 0x400000.