Poweradmin has Host Header Injection in OIDC redirect_uri, SAML ACS/SLO URL, and Logout Redirect Construction.
Summary
Poweradmin v4.3.2 uses the attacker-controlled HTTP_HOST request header as the
authoritative source for building callback URLs in its OIDC, SAML, and logout
authentication flows without any validation. An unauthenticated attacker can poison
the redirect_uri sent to the Identity Provider, causing the IdP to redirect the
victim's authorization code to an attacker-controlled server - resulting in full
account takeover with no credentials required.
Three independent code paths are affected:
- Primary (Critical):
OidcService::getCallbackUrl() - redirect_uri poisoning - Secondary (High):
SamlConfigurationService::getBaseUrl() - SAML ACS/SLO URL poisoning - Tertiary (Medium):
LogoutController::getBaseUrl() - post-logout redirect poisoning
Details
*Root Cause*
The application constructs absolute URLs dynamically from HTTP_HOST rather than
from a trusted configured base URL. The header is fully client-controlled and is not
validated before use in any authentication flow.
Poweradmin's own codebase contains the correct pattern -
DocsController::getValidatedHost() (line 244) calls isValidHostname() before
using the value - but this was never applied to authentication flows.
Primary: lib/Application/Service/OidcService.php (~line 460)
```php
private function getCallbackUrl(): string
{
$scheme = $this->detectScheme();
// HTTP_HOST taken directly with zero validation
$host = $this->request->getServerParam('HTTP_HOST', 'localhost');
$basePrefix = $this->configManager->get('interface', 'base_url_prefix', '');
return $scheme . '://' . $host . $basePrefix . '/oidc/callback';
}
HTTP_HOST is embedded verbatim as redirect_uri in the OAuth 2.0 authorization
request sent to the IdP. HTTP_X_FORWARDED_PROTO is similarly used unvalidated
for scheme detection.
Secondary: lib/Application/Service/SamlConfigurationService.php (~line 134)
private function getBaseUrl(): string
{
$configuredBaseUrl = $this->configManager->get('interface', 'base_url', '');
if (!empty($configuredBaseUrl)) {
return rtrim($configuredBaseUrl, '/'); // safe path - rarely configured
}
// Falls through on every default installation
$host = $_SERVER['HTTP_HOST'] ?? 'localhost';
...
return $scheme . '://' . $host . $prefix;
}
Used to construct SAML ACS URL, SLO URL, and entity ID - all poisonable via Host header.
The safe fallback only activates when interface.base_url is explicitly set, which is
optional and empty by default.
Tertiary: lib/Application/Controller/LogoutController.php (~line 272)
Same $_SERVER['HTTP_HOST'] pattern used for post-logout redirect URL construction.
PoC
Environment: Poweradmin v4.3.2, Docker, PHP 8.2, OIDC enabled, interface.base_url empty (default).
docker exec poweradmin-container php -r "
require '/app/vendor/autoload.php';
putenv('PA_CONFIG_PATH=/app/config/settings.php');
use PowerAdmin\Application\Service\OidcService;
use PowerAdmin\Infrastructure\Configuration\ConfigurationManager;
use PowerAdmin\Infrastructure\Web\Request;
\$_SERVER['HTTP_HOST'] = 'attacker.com';
\$_SERVER['HTTPS'] = '';
\$config = ConfigurationManager::getInstance();
\$request = new Request();
\$oidcService = new OidcService(\$config, \$request);
\$authUrl = \$oidcService->initiateAuthFlow('test');
parse_str(parse_url(\$authUrl, PHP_URL_QUERY), \$p);
echo 'redirect_uri: ' . urldecode(\$p['redirect_uri']) . PHP_EOL;
if (str_contains(\$p['redirect_uri'], 'attacker.com')) {
echo '[CONFIRMED] Host header injection successful' . PHP_EOL;
}
"
Output:
redirect_uri: http://attacker.com/oidc/callback
[CONFIRMED] Host header injection successful - redirect_uri contains attacker.com
The redirect_uri in the authorization request sent to the Identity Provider is
http://attacker.com/oidc/callback. The victim's authorization code will be
delivered to this URL upon successful authentication.
Note on PKCE: PKCE does not mitigate this attack. The attacker initiates the
flow themselves and controls both code_challenge and code_verifier.
Impact
Direct Impact
An attacker who can send a request with a spoofed Host header - directly or via a
misconfigured reverse proxy (proxy_set_header Host $http_host is the nginx default) -
can steal any user's authorization code and gain full authenticated access to Poweradmin.
No credentials, malware, or prior access required.
DNS Infrastructure Impact
Poweradmin manages PowerDNS. A compromised administrator account grants full DNS zone
control, enabling:
- MX hijacking - redirect all inbound email to attacker's mail server; intercept
password reset emails and 2FA codes for any third-party service registered with
