[SOLVED] form input hack

[EchoFool]

I don't know how but a user managed to input "something" into my script which got through all my validation yet he still managed to get a number input which according to my logs says +99999999  (dont know how the + got through)!

 

 

I have this as a validation check:

 

$StrengthInputOriginal = mysql_real_escape_string($_POST['strength']);
If($StrengthInputOriginal == '' OR !(number_format($StrengthInputOriginal))){
$StrengthInputOriginal = 0;
}

 

The log of the user shows:

 

Trained agility input +9999999999999 for gain of 8896888888890

 

How could such a number get through i even check its not that high of a number be he still managed it =/

[Maq]

I'm not sure but maybe the number_format accepts the '+' sign because it's thinking they're assigning it a positive value.  ???  You might be better off checking it with a regular expression as well.

[EchoFool]

can you give me an example of what you mean ?

[DarkWater]

How about the is_numeric() function?  Also, you'd probably want to create a 'range' of acceptable values. >_<

[Psycho]

I'm assuming the database field is set as an int type. If that's the case you only need to verify that the input is an integer - no need for mysql_real_escape_string().

 

And, number_format() would have no effect in the manner in which you are using it. According to the manual its oly return values are "A formatted version of number." So, it doesn't return false if the value is not a properly formatted number.

[trq]

no need for mysql_real_escape_string().

 

mysql_real_escape_string should be applied to any and all user inputted data.

[EchoFool]

Trained strength input +9999 for gain of 39.996  < he still got through!!

 

Even though my gain shows 39.996 on the log its giving him like 900000 + i don't get what the hell he is inputting but its get throughts every time!

 

How do i check its integer only.

[Maq]

Do not use number_format or is_numeric because they both will accept the '+'  and '-' signs.  I suggest you use a regex if you want purely numbers.  This way you could make the input field more precise.

[DarkWater]

/^\d+$/

 

That would be the regex you're looking for, if you want to use that route.

[EchoFool]

<input type="text" size="16" name="strength" value="">

 

 

<?php
$StrengthInputOriginal = mysql_real_escape_string($_POST['strength']);
If($StrengthInputOriginal == '' OR !(is_int($StrengthInputOriginal)) OR strlen($StrengthInputOriginal)>2){
$StrengthInputOriginal = 0;
}
?>

 

This doesn't seem to accept any number i put in.. it just gives me 0 every time :S

[The Little Guy]

number_format does not return TRUE/FALSE, it returns a number...

 

maybe you should try is_numeric()

[Maq]

number_format does not return TRUE/FALSE, it returns a number...

 

maybe you should try is_numeric()

 

Like I said is_numeric will accept the '+' sign.

 

Finds whether the given variable is numeric. Numeric strings consist of optional sign, any number of digits, optional decimal part and optional exponential part. Thus +0123.45e6 is a valid numeric value.

 

You should use the regex that DW provided.

[EchoFool]

Whats the syntax for checking with regex?

 

 

Is it:

 

 

 

<?php
If( (preg_match('/^\d+$/',$StrengthInputOriginal) == FALSE){

// yay
}Else{
// boo 
}
?>

[DarkWater]

if (!preg_match('^\d+$', $StrengthInputOriginal) {
    //bad
}
else {
    //good
}

[The Little Guy]

$str = array('a999','999','+999','99-99');
foreach($str as $s){
     if(preg_match('~^[0-9]+$~',$s)){
     echo $s.': good<br>';
     }else{
     echo $s.': bad<br>';
     }
}

[Maq]

Damnit DW, you always beat me to it!  >

[EchoFool]

Warning: preg_match() [function.preg-match]: No ending delimiter '^' found in gymstat.php on line 23

 

My val:

 

<?php
$StrengthInputOriginal = mysql_real_escape_string($_POST['strength']);
If(!(preg_match('^\d+$', $StrengthInputOriginal))) {
$StrengthInputOriginal = 0;
}
?>

[The Little Guy]

<?php
$StrengthInputOriginal = mysql_real_escape_string($_POST['strength']);
If(!(preg_match('~^\d+$~', $StrengthInputOriginal))) {
   $StrengthInputOriginal = 0;
   }
?>

[EchoFool]

Thanks everyone