PIAF-HMS multiple unauthenticated SQL injection vulnerabilities via mysql_query

claudiopizzillo PIAF-HMS (PBX-In-A-Flash Hotel Management System; no released versions, latest commit 389d2633441b65ced1c104212cd62be2bfca21e5) contains multiple unauthenticated SQL injection vulnerabilities. The application has no authentication mechanism and passes user-supplied HTTP parameters directly into deprecated mysql_query() calls via string concatenation, without sanitization, escaping, or parameterization. Affected sinks include rooms.php (DELETE FROM Rooms WHERE ID = $_GET['ID'], unquoted numeric context), checkuser.php (WHERE Ext = '$_GET["Ext"]'), ec.php (date/extension parameters in a WHERE), checkin.php and wakeup.php ($_POST values into INSERT statements), bills.php ($_POST fields built into a WHERE clause), and rates.php and checkout.php. A remote, unauthenticated attacker can inject arbitrary SQL to read, modify, or delete arbitrary records in the backing database (e.g. rooms.php?ID=1 OR 1=1 deletes all room records). Note: queries run via the legacy mysql_* extension, which does not permit stacked statements.