libcli/smb/smbXclibase.c in Samba 4.x before 4.2.14, 4.3.x before 4.3.11, and 4.4.x before 4.4.5 allows man-in-the-middle attackers to bypass a client-signing protection mechanism, and consequently spoof SMB2 and SMB3 servers, via the (1) SMB2SESSIONFLAGISGUEST or (2) SMB2SESSIONFLAGIS_NULL flag.
{ "availability": "No subscription required", "ubuntu_priority": "medium", "binaries": [ { "libwbclient-dev": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-libs": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "registry-tools": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-common-bin": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libsmbsharemodes0-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libwbclient0-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libpam-winbind-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libnss-winbind-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-doc": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libsmbsharemodes0": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-vfs-modules": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "winbind": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "python-samba-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-dsdb-modules-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libsmbsharemodes-dev-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-common-bin-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-testsuite": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-dev-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "smbclient-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libsmbclient": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libsmbsharemodes-dev": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libsmbclient-dev": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libwbclient0": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libparse-pidl-perl-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-dsdb-modules": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "registry-tools-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-vfs-modules-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "python-samba": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libpam-smbpass-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libsmbclient-dev-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libnss-winbind": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libsmbclient-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-libs-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-dbg": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-testsuite-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-common": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "winbind-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libpam-winbind": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "smbclient": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libwbclient-dev-dbgsym": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "samba-dev": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libparse-pidl-perl": "2:4.3.11+dfsg-0ubuntu0.14.04.1", "libpam-smbpass": "2:4.3.11+dfsg-0ubuntu0.14.04.1" } ] }
{ "availability": "No subscription required", "ubuntu_priority": "medium", "binaries": [ { "libwbclient-dev": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-libs": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "registry-tools": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-common-bin": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "libwbclient0-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-dsdb-modules-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "libpam-winbind-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "libnss-winbind-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "winbind": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-vfs-modules": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-common-bin-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-testsuite": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-dev-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "smbclient-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "libsmbclient": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "libsmbclient-dev": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "libwbclient0": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "libparse-pidl-perl-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-dsdb-modules": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "registry-tools-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-vfs-modules-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "python-samba": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "ctdb": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "libsmbclient-dev-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "libnss-winbind": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "libsmbclient-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-libs-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-dbg": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-testsuite-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-common": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "winbind-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "libpam-winbind": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "smbclient": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "libwbclient-dev-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "samba-dev": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "libparse-pidl-perl": "2:4.3.11+dfsg-0ubuntu0.16.04.1", "ctdb-dbgsym": "2:4.3.11+dfsg-0ubuntu0.16.04.1" } ] }