The vulnerability description explicitly names the order and group methods in Zend_Db_Select as vulnerable entry points. The security advisory ZF2016-03 details that these methods didn't properly handle SQL comments in input parameters, allowing attackers to bypass validation. Both methods process user-provided SQL fragments for ORDER BY and GROUP BY clauses without adequate comment stripping, making them direct vectors for injection. The patch specifically targeted these methods by adding comment removal logic, confirming their vulnerable status.