Re: [exim] pgsql login allowing mysterious sending

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Autor: Chris Wilson
Data:  
Para: Mark Adams
CC: exim-users
Asunto: Re: [exim] pgsql login allowing mysterious sending
Hi Mark,

On Tue, 4 May 2010, Mark Adams wrote:

> An example of one of the spam mails being sent out shows in the log as
> follows; note that instead of rejecting the login it just shows as
> blank.
>
> 1O8epJ-0006Ft-Sj <= nlexluon@??? H=(geembr.com)
> [59.35.97.251] P=esmtpa A=pgsql_login: S=2743
> id=d5d9f8280c874dbe93f0564fd56a8d83@fb9d2058f7ab4242ae7bbe23bd70bf11
>
> I've tested myself with blank user/pass and it shows an authentication
> failure as it should -- how are they getting through here?? Any help
> appreciated.


Have you tried a blank username with a password?
> pgsql_login:
>        driver = plaintext
>        public_name = LOGIN
>        server_prompts = "Username:: : Password::"
>        server_condition = \
>        ${if and {{eq{$1}{${lookup pgsql \
>        {SELECT userid || '@' || domain FROM fn_mail_user_get_active_smtp ('${quote_pgsql:$1}')}}}}\
>        {eq{$2}{${lookup pgsql\
>        {SELECT password FROM fn_mail_user_get_active_smtp ('${quote_pgsql:$1}')}}}}}{yes}{no}}
>        server_set_id = $1


It looks like you're using PostgreSQL "table functions" in your queries.
Without knowing what those functions do, it's difficult to tell what might
be happening. You might like to avoid them in order to diagnose the
problem.

It's possible that these queries return multiple rows in random
order.

It's possible that you have a user with no password in your
database and the spammer somehow got lucky in selecting that user.

I think it's unsafe to use $1 and $2 because they could be modified by
matching during the query.

Another user reported a problem with server_set_id last week that might be
related, you could search the archives for it.

Have you tried a blank username with a non-blank password?

Cheers, Chris.
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