First published: Mon Dec 02 2013(Updated: )
It was reported [1] that Samba's pam_winbind module would fail open (allowing access) when the require_membership_of option is used as an argument to pam_winbind, and contains a non-existent group as the value. In such a configuration, rather then failing and not permitting authentication which is what would be expected, pam_winbind will allow authentication to proceed. For instance, if the following is specified and the user is not a member of the group 'Admin', they will not obtain access to the system: auth sufficient pam_winbind.so use_first_pass require_membership_of=Admin On the other hand, if the non-existent group 'AdminOops' is specified, the user is obviously not a member of said group, authentication will be permitted: auth sufficient pam_winbind.so use_first_pass require_membership_of=AdminOops The commit [2] that most likely introduced this flaw indicates that this was introduced October 2009 and another commit [3] looks like the fix, although that is for another bug [4] that's somewhat related to this issue and somewhat not. [1] <a href="https://lists.samba.org/archive/samba-technical/2012-June/084593.html">https://lists.samba.org/archive/samba-technical/2012-June/084593.html</a> [2] <a href="http://git.samba.org/?p=samba.git;a=commit;h=31f1a36901b5b8959dc51401c09c114829b50392">http://git.samba.org/?p=samba.git;a=commit;h=31f1a36901b5b8959dc51401c09c114829b50392</a> [3] <a href="http://git.samba.org/?p=samba.git;a=commitdiff;h=f62683956a3b182f6a61cc7a2b4ada2e74cde243">http://git.samba.org/?p=samba.git;a=commitdiff;h=f62683956a3b182f6a61cc7a2b4ada2e74cde243</a> [4] <a href="https://bugzilla.samba.org/show_bug.cgi?id=8598">https://bugzilla.samba.org/show_bug.cgi?id=8598</a>
Credit: secalert@redhat.com
Affected Software | Affected Version | How to fix |
---|---|---|
Samba Samba | >=3.3.10<3.4.0 | |
Samba Samba | >=3.4.3<3.6.22 | |
Samba Samba | >=4.0.0<4.0.13 | |
Samba Samba | >=4.1.0<4.1.3 | |
Canonical Ubuntu Linux | =10.04 | |
Canonical Ubuntu Linux | =12.04 | |
Canonical Ubuntu Linux | =12.10 | |
Canonical Ubuntu Linux | =13.04 | |
Canonical Ubuntu Linux | =13.10 |
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