Re: Use PPI to Find SQL Injection Attacks

[jZed]

Unless I'm misreading, some of the more serious false negatives include:

$dbh->do(qq{
    /* comment */ INSERT INTO foo VALUES('$bad_stuff')
});
$dbh->do(qq{
   INSERT INTO foo VALUES($bad_stuff)
});
$dbh->do( sprintf(
 "INSERT INTO foo VALUES(%s)", $bad_stuff
));

A better approach might be to find all the prepare() and do() statements and run them through a safe DBI subclass that does the prepare and evaluates what it prepared.

[Ovid]

Excellent points on the SQL. I like the DBI subclass idea. Can you point me to some examples? I've never tried to do anything like that before.

[jZed]

A minimal DBI subclass can be found here: Interpolate binds into SQL on error - DBI subclassing (possibly not the best example but since I wrote it I knew where to find it :-)). Basically you'd need to redefine execute() to do nothing, and redefine prepare() (in MyDBI::db) to do your injection checking.