On 11/06/2014 12:35 PM, Alexander Bokovoy wrote:
On Thu, 06 Nov 2014, thierry bordaz wrote:
On 11/05/2014 09:14 PM, Nathaniel McCallum wrote:
Before this patch users could log in using only the OTP value. This
arose because ipapwd_authentication() successfully determined that
an empty password was invalid, but 389 itself would see this as an
anonymous bind. An anonymous bind would never even get this far in
this code, so we simply deny requests with empty passwords.

This patch resolves CVE-2014-7828.


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Hello Nathaniel,

  With the DS flag 'nsslapd-allow-unauthenticated-binds', customer
  have the ability to allows unauthenticated binds and connections.
  With the fix, a ldapclient bind containing only OTP part will fail
  even if the flag was set.
By definition of nsslapd-allow-unauthenticated-binds, it requires a BIND
with name but no password. Specifying OTP value will make password
non-empty and thus failing unauthenticated bind request definition.

Hello Alexander,

   I agree that regarding the RFC, there is unauthenticated bind when
   the password is empty. The question is when the test of empty
   password should be done.
   On DS implementation, the toggle
   ('nsslapd-allow-unauthenticated-binds') is enforced in frontend when
   the password is untouched (and so not empty).
   Later in backend bind, the password has been stripped from its OTP
   part and being now emptied the backend considere the connection to
   be anonymous authorized. Should DS also enforce the toggle at
   backend level ?

   In that sense that means that the fix (test of password len to
   reject the bind) could/should rather be done in DS backend than in
   the preop plugin.


  When ipapwd_pre_bind, stipping the OTP part, detects that the
  password is zero length, I wonder if it should not test that flag to
  determine if it should fail or succeed.
Since original password was non-empty it wouldn't make sense to check
the value for empty password after stripping the OTP part as it is not
an unauthenticated password in the first place.

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