[Dovecot] LDAP encryption

[Timo Sirainen]

I don't think you can do that with a plugin without core Dovecot modifications. Unless you replace the whole passdb ldap. For example you could use passdb checkpassword if performance isn't a big issue.

On 9.10.2012, at 22.24, James Devine wrote:

> Here is an example of the problem:
> 
> Oct  9 13:19:53 smtp-outgoing2 dovecot: auth: Debug:
> password(user at domain.tld,192.168.160.49): Generating NTLM from user
> 'user at domain.tld@', password 'IfBG6G3jykirE5r5vienC4w=='
> Oct  9 13:19:53 smtp-outgoing2 dovecot: auth: Debug:
> password(user at domain.tld,192.168.160.49): Credentials:
> f124dc24328ed3d90db035f0d5284636
> 
> The listed password is a base64 representation of its encrypted form which
> I need to somehow decrypt between the time LDAP returns it and these
> credentials are generated.
> 
> 
> 
> On Tue, Oct 9, 2012 at 1:16 PM, James Devine <fxmulder at gmail.com> wrote:
> 
>> I don't think I understand.  Right now the problem is the password
>> retrieved from LDAP cannot be hashed to compare against what the user sent
>> because it is encrypted.  I have to perform my AES decryption before it can
>> be hashed and compared.
>> 
>> 
>> On Tue, Oct 9, 2012 at 1:03 PM, btb <btb at bitrate.net> wrote:
>> 
>>> On 2012.10.09 14.41, James Devine wrote:
>>> 
>>>> We have an LDAP server that contains AES encrypted passwords.  So far
>>>> I've
>>>> been able to use this by adding a passdb module that encrypts the user's
>>>> password prior to ldap comparison.  Now I am looking at supporting
>>>> client-side encrypted passwords.  To do this I need to decrypt the
>>>> password
>>>> returned by LDAP.  Is there a way to insert a module to do this
>>>> decryption
>>>> between ldap returning and the auth mechanism?
>>>> 
>>>> that would be unwise, generally speaking.  as a rule of thumb, in terms
>>> of security fundamentals, only the rootdn [or equiv] should be able to read
>>> the values in an ldap entry's password attribute.  certainly the service
>>> account used by dovecot should not.
>>> 
>>> in the context of ldap, authentication should be accomplished by binding
>>> as the user, not by retrieving attribute values and performing string
>>> comparisons.  among other things, this decouples the two components and
>>> allows applications [e.g. dovecot] to be unconcerned with whatever password
>>> hashing scheme the directory server might be using.
>>> 
>>> -ben
>>> 
>> 
>>