Date: Wed, 5 Jun 2013 23:07:19 -0400
From: David H <ispcolohost@...il.com>
To: "full-disclosure@...ts.grok.org.uk" <full-disclosure@...ts.grok.org.uk>
Subject: Re: Plesk Apache Zeroday Remote Exploit

I don't have an interest in disproving anything or defending Plesk as it is
mostly bug-ridden garbage, the purpose of my post was to try and determine
in which scenarios the exploit is possible so those who are vulnerable can
help themselves.

Like I said in my email, as best I can tell, the ScriptAlias directive that
the exploit states as being a requirement for the vulnerability, would
never appear on a Plesk 8 server since Plesk 8, at least on CentOS, never
offered the ability to run php as a cgi.  I also could not find the
required directive existing on a Plesk 9.5.4 server; on there php cgi
requests are fed to their wrapper script.

I've since seen some other discussion of this on Reddit and someone on
there confirmed the bad directive was present on a Plesk 9.2 server.  It
sounds like any Plesk version 9.x prior to 9.5.4 would be vulnerable on any
IP where the site in question is set to run php in cgi mode.  I do not
believe it would be possible to perform the attack if php were set to
apache module.  Of course Plesk 9.x prior to 9.5.4 with all updates applied
has numerous known vulnerabilities so this would be an addition to that
list.

I do believe if there is any platform where php as a cgi is the default
config, it would be vulnerable as well if not patched because Plesk would
keep that default.

I would be interested in knowing if anyone has a Plesk 8 server where the
[scriptAlias /phppath/ "/usr/bin/"] is present; I have not been able to
find one and have not been able to find a Plesk 8 server where this exploit
works.




On Wed, Jun 5, 2013 at 10:28 PM, Kingcope <
isowarez.isowarez.isowarez@...glemail.com> wrote:

> Dave ,
> Again bla bla,
> Dont Lie!!! I tested and it Works proper !! Tested on Centos Red Hat
> Debian FreeBSD !! Pure Remote in the Wild !! Better Patch Ur Servers and
> Check Ur perimeter than Telling lies.
>
> Me mixanaki Kai Computer Kai flogera!
>
> Cheerio,
>
> Kctherookie
>
> Am 06.06.2013 um 00:37 schrieb David H <ispcolohost@...il.com>:
>
> > Sorry for improper reply; was not a member of the list until today so I
> didn't have the original email to reply to.
> >
> > As best I can tell, this exploit only works on very specific
> configurations that may or may not actually be related to Plesk; I'm not
> able to tell because I have not found a version of Plesk that the
> vulnerability worked on to be able to determine why.  I was only able to
> reproduce this issue on one server and it turns out there was a very weird
> reason why it worked.
> >
> > The server in question was Plesk 8.6 on CentOS 5.  On that particular
> server, the exploit only worked on IP addresses that were set to 'shared'
> in Plesk, it did not work on any IP set to exclusive that had a default
> website configured to be served.
> >
> > Additionally, there was no reference to phppath in any of the apache
> config files on the system in /etc/httpd/conf/, /etc/httpd/conf.d/, or
> /var/www/vhosts/*/conf/ where all the included domain config files are so I
> was really struggling to figure out why that was working.
> >
> > Turns out on this specific server the server owner had an issue where
> some of his hosted domain owners liked to type in https:// in front of
> their domain even if they did not use SSL and were on the shared IP
> address.  Normally, by default for Plesk, if a site on a shared IP does not
> have SSL enabled, you'll get the Plesk banner page instead of the website
> you typed in, which is served from /var/www/vhosts/default/htdocs/.  This
> customer had some complaints from those users, so he put a copy of
> /usr/bin/php-cgi in /var/www/vhosts/default/cgi-bin/, used a .htaccess to
> enable php for those default requests, then rewrote all requests coming in
> over https:// to index.php where a redirect was done in php to the
> non-secure equivalent of the domain requested.  (Just using rewrite rules
> would have worked too but whatever...)
> >
> > It appears this was set up a couple years ago and since this was CentOS
> 5, the copy of /usr/bin/php-cgi taken at the time was vulnerable to the
> cve-2012-1823 issue.  Copying /usr/bin/php-cgi over top of
> /var/www/vhosts/default/cgi-bin/php-cgi resolved the issue.  If this was
> not related to cve-2012-1823 I would not have expected that solution to
> work, since the only change was copying the latest CentOS 5 php-cgi over
> top of a several year old version of the same file.  Additionally, prior to
> doing that, I modified the exploit script to execute 'ls' and got the
> contents of the /var/www/vhosts/default/htdocs/ directory.  Based on the
> description of the exploit and the expectation that it is running by using
> a direct execution of /usr/bin/php, I would have expected to get the
> contents of /usr/bin/ instead?
> >
> > Now, keep in mind that Plesk 8 did not allow you to select to select to
> run php as a fastcgi or cgi, only php on or php off.  I'm only familiar
> with Plesk on CentOS but this means that without a custom config, there is
> no way to run a website on an install of Plesk 8 on CentOS with php set to
> run as a cgi, only apache module, and the exploit doesn't seem to work in
> that case.
> >
> > Plesk 9 did add the option to run php as fastcgi or cgi.  After some
> searching around online, I did find reference to the 'phppath' alias in
> some Plesk forum posts but they were for platforms other than CentOS and
> not Plesk 8, so unless I'm missing it, I don't think the ScriptAlias
> /phppath/ is used on Plesk 8 or 9 on CentOS with the CentOS-provided php.
> >
> > I know my situation was very weird, so I'm just theorizing now, but I'm
> kind of thinking at this point that perhaps the exploit only works in the
> following specific situations:
> >
> > 1) If the server in question runs an OS where php executes as a cgi by
> default instead of as an apache module, AND either the OS vendor has not
> released a patched php-cgi for cve-2012-1823 or the server owner is not up
> to date on their patches.  My example of just copying the OS php-cgi over
> top of the one that had been in use on the single instance resolved it, so
> that's what lead me to that conclusion.  I do not know which
> Plesk-supported OS's run php as a cgi by default.
> >
> > 2) If the server in question runs Plesk 9, AND the server admin or site
> owner has set php to run as a cgi, AND the php-cgi has not been patched for
> cve-2012-1823.
> >
> > In CentOS/RHEL, if you install httpd and mod_php, the default config is
> to run it as an apache module and this exploit did not work in those
> situations; same with Plesk 9.  I also attempted to set php to run as a cgi
> on a few sites on Plesk 9 on CentOS 5 and the exploit did not work, but all
> of the CentOS 5 servers I have access to have their php rpm up to date
> which means it is patched for cve-2012-1823.  CentOS 4 was never php 5 so
> it was not vulnerable to cve-2012-1823 to begin with and Plesk 8 and Plesk
> 9 on that platform don't seem to be vulnerable.
> >
> > If someone has an out of date copy of CentOS 5 running Plesk 9, it would
> be interesting to set a site to run php as a cgi and then hit it with the
> script to see if the exploit works.  If it does, then it's the
> cve-2012-1823 issue and just unpatched servers causing the problem, but
> only when the exploit hits a website that has php set to run as a cgi, or
> the OS runs it as a cgi by default (don't know which ones do that).
> >
> > Dave
> >
> >
> >
> > From: king cope <isowarez.isowarez.isowarez () googlemail com>
> > Date: Wed, 5 Jun 2013 18:37:38 +0200
> > Please keep headers intact.
> >
> > Engineered by Kingcope
> >
> > Copyright (C)2013 Kingcope
> > Attachment: pleskwwwzeroday.rar
> > _______________________________________________
> > Full-Disclosure - We believe in it.
> > Charter: http://lists.grok.org.uk/full-disclosure-charter.html
> > Hosted and sponsored by Secunia - http://secunia.com/
>

Content of type "text/html" skipped

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/

Powered by blists - more mailing lists