Is there an SQL injection possibility even when using mysql_real_escape_string()
function?
Consider this sample situation. SQL is constructed in PHP like this:
$login = mysql_real_escape_string(GetFromPost('login'));
$password = mysql_real_escape_string(GetFromPost('password'));
$sql = "SELECT * FROM table WHERE login='$login' AND password='$password'";
I have heard numerous people say to me that code like that is still dangerous and possible to hack even with mysql_real_escape_string()
function used. But I cannot think of any possible exploit?
Classic injections like this:
aaa' OR 1=1 --
do not work.
Do you know of any possible injection that would get through the PHP code above?
Answer
Consider the following query:
$iId = mysql_real_escape_string("1 OR 1=1");
$sSql = "SELECT * FROM table WHERE id = $iId";
mysql_real_escape_string()
will not protect you against this.
The fact that you use single quotes (' '
) around your variables inside your query is what protects you against this. The following is also an option:
$iId = (int)"1 OR 1=1";
$sSql = "SELECT * FROM table WHERE id = $iId";
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