Zendframework1 Potential SQL injection in ORDER and GROUP functions

The implementation of ORDER BY and GROUP BY in Zend_Db_Select remained prone to SQL injection when a combination of SQL expressions and comments were used. This security patch provides a comprehensive solution that identifies and removes comments prior to checking validity of the statement to ensure no SQLi vectors occur.

The implementation of ORDER BY and GROUP BY in Zend_Db_Select of ZF1 is vulnerable by the following SQL injection:

$db = Zend_Db::factory(/* options here */);
$select = new Zend_Db_Select($db);
$select->from('p');
$select->order("MD5(\"a(\");DELETE FROM p2; #)"); // same with group()

The above $select will render the following SQL statement:

SELECT `p`.* FROM `p` ORDER BY MD5("a(");DELETE FROM p2; #) ASC

instead of the correct one:

SELECT "p".* FROM "p" ORDER BY "MD5(""a("");DELETE FROM p2; #)" ASC

This security fix can be considered an improvement of the previous ZF2016-02 and ZF2014-04 advisories.

As a final consideration, we recommend developers either never use user input for these operations, or filter user input thoroughly prior to invoking Zend_Db. You can use the Zend_Db_Select::quoteInto() method to filter the input data, as shown in this example:

$db    = Zend_Db::factory(...);
$input = "MD5(\"a(\");DELETE FROM p2; #)"; // user input can be an attack
$order = $db->quoteInto("SQL statement for ORDER", $input);

$select = new Zend_Db_Select($db);
$select->from('p');
$select->order($order); // same with group()