I have very short question, but no one asked it yet. Is it posible to do SQL injection in such piece of code?:
$number = intval($_GET["number"];
mysqli_query($link, "Select Username FROM Users WHERE USER_ID = $number");
Thank you.
Thanks to using intval()no, so you are fine.
But: mysql_query() is deprecated (http://php.net/manual/en/function.mysql-query.php). Consider using MySQLi or PDO_MySQL.
No because intval will always just be a number. The same goes for (int).
Related
$id = $_GET['id'];
$result = mysql_query("select Count(id='$id') As Total from topics");
The above code is only working if we put count(id) but i want to get count of selected variable. How to insert id='$id' in count function it is not working please help related this.
You want a where clause in your sql query, which I believe would look like this:
select count(id) As Total from topics where id='$id'
note: depending on what type of column you have for your id field, you might need to drop the single quotes.
Warning
your code is vulnerable to sql injection you need to escape all get, post and request and the better approach will be using Prepared statement
Good Read
How to prevent SQL injection in PHP?
Are PDO prepared statements sufficient to prevent SQL injection?
Note
The entire ext/mysql PHP extension, which provides all functions named with the prefix mysql_, is officially deprecated as of PHP v5.5.0 and will be removed in the future. So use either PDO or MySQLi
Good read
The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead
PDO Tutorial for MySQL Developers
Pdo Tutorial For Beginners
Your question isn't very clear but perhaps you're looking for COUNT CASE WHEN id = $id THEN 1 ELSE 0 END (you can even skip the ELSE 0 part I believe).
What actually are you trying to do is pretty unclear in the Question.
But if you are trying to count the number of rows then simple select count(*) as Total where {your condition} from table will will do for you.
$id get values of $_GET['id']
if you want other data, use $id="your data here"
The following should work:
$id = $_GET['id'];
$result = mysql_query("SELECT COUNT(`" . $id . "`) AS `Total` FROM `Topics`");
But do note that this isn't very secure since it will be vulnerable to SQL Injection attacks.
Count can be used as below
<?php
$shoes=array("nike","puma","lancer");
echo count($shoes);
?>
Read the documentation in the PHP manual on Count.For inserting id in count:
$result = mysql_query('SELECT COUNT(id) FROM clients');
$count = mysql_result($result,0);
echo $count;
This question already has answers here:
How can I prevent SQL injection in PHP?
(27 answers)
Closed 9 years ago.
I know i am not secure when i am using this code so anything i can add in my code?
I have tried my self sql injection they are somewhere working but not much as i dont have much knowledge about sql injection. but as hacker are more smart so they can really hack my website.
Url looks like this :
http://example.com/profile.php?userID=1
php
$userID = $_GET['userID'];
$userID = mysql_real_escape_string($userID);
$CheckQuery = mysql_query("SELECT * FROM tbl_user WHERE id='$userID'");
$CheckNumber = mysql_num_rows($CheckQuery);
if ($CheckNumber !== 1)
{
header("Location: tos.php");
}
I tried:
http://example.com/profile.php?userID=1'
which hide many things on site.
when i tried
http://example.com/profile.php?userID=1' UNION SELECT * FROM tbl_user; with havij it was hacked
Thanks :|
use mysqli::prepare or at least sprintf
mysql_query(sprintf("SELECT * FROM tbl_user WHERE id='%d'", $userID);
$db = new mysqli(<database connection info here>);
$stmt = $db->prepare("SELECT * FROM tbl_user WHERE id='?'");
$stmt->bind_param("id", $userID);
$stmt->execute();
$stmt->close();
Dont use mysql_* functionality at all.
Use PDO or mysqli.
http://php.net/PDO
http://php.net/mysqli
PDO will escape your data for you.
But for your current code:
$userID = $_GET['userID'];
$userID = mysql_real_escape_string($userID);
if(ctype_digit($userID))
{
$CheckQuery = mysql_query("SELECT * FROM tbl_user WHERE id='$userID'");
$CheckNumber = mysql_num_rows($CheckQuery);
if ($CheckNumber !== 1)
{
header("Location: tos.php");
}
} else {
// THE USER ID IS NOT ALL NUMBERS, CREATE AN ERROR
}
I know i am not secure when i am using this code
This statement is wrong.
As a matter of fact, this very code is pretty secure.
And none of the codes you provided below would do any harm. Why do you think it is not secure?
This way is not recommended, yes. And the way you are using to format your queries may lead to injection for some other query. But the present code is perfectly secure.
As long as you are enclosing every variable in quotes and escape special chars in it - it is safe to be put into query.
Only if you omit one these two rules (i.e. escape but don't quote or quote but don't escape) - you are in sure danger. But as long as you're following both, you're safe.
The only reason for "hacking" I can guess of is a single quote used in HTML context. In some circumstances it can "hide many things on the page". But for the SQL, with the code you posted here, it's harmless
Look, out of this link
http://example.com/profile.php?userID=1'
your code will produce such a query
SELECT * FROM tbl_user WHERE id='1\''
which is quite legit for mysql and will even return a record for id=1, as it will cast 1' to 1 and find the record. This is why there is no redirect to tos.php.
So, the problem is somewhere else.
either there is a code that does not follow the rules I posted above
or this problem is unrelated to SQL at all - so, you are barking wrong tree and thus still keep whatever vulnerability open
Most likely you have to echo your values out
u can try type casting the value
<?php
$CheckQuery = mysql_query("SELECT * FROM tbl_user WHERE id='".(int)$userID."'");
?>
I am using following method for MySQL queries:
$sql = "SELECT * FROM mytable WHERE `myTableId`=" . (int)$myId;
Is this a completely safe method or is there a way to inject some sql into the database with this method?
Any better alternative?
It can lead to unintended consequences, e.g.
$myId = 'blahblahblah';
would result in
... WHERE myTableId=0
maybe not such a big deal in this case, but if (say) you're doing a permissions systme and "super-duper-ultra-high-level-user-with-more-power-than-god" has permission level 0, then it's a nice way to bypass security.
If you truly want to avoid SQL injection, your best bet is to use PDO and prepared statements. check out http://www.php.net/pdo and http://www.php.net/manual/en/pdo.prepare.php
Thís should be perfectly save, without any drawbacks, as long as the input can be casted to int.
make it like this
$sql="select `username` from `users` where id='$newid';";
mysql_query($sql);
here $newid is the int value.
The symbol used before and after username, to get this you have to press the key just below esc .
I would probably use sprintf instead - but I dont see that it is much different from what you are doing. Placing the integer in quotes may also help.
$sql = sprintf("SELECT * FROM mytable WHERE `myTableId`='%d'", $myId);
Should probably add that you may want to deal with the case when conversion to integer fails. So dont have a table zero.
No need for the Int if you are just worrying about the mysql injection.
To prevent mysql injection you can use mysql_real_escape_string.
What you have right now will block all mysql injection if your mysql condition is only for int but if the situation is like this:
$username = $_GET["username"];
SELECT * FROM customers WHERE username = '$username'
if the $username value is *\' OR 1* your in trouble or i should say your dead
if the $username value is *\'; DELETE FROM customers WHERE 1 or username = * your very dead + doomed
To prevent this from happening use mysql_real_escape_string
$username = mysql_real_escape_string($_GET["username"]);
I've been coding my website in PHP lately and I was pretty proud of myself for my good practices of sanitizing my input before I used it in a query. It was all going great until my friend said I need to sanitize my input. When I tried to explain to him that it was sanitized, he showed me that he had found everything in 'users' table in my database. I didn't know how, so I thought I would post what I was doing wrong that made my sanitizing not work. Here is the PHP code he was exploiting:
start_mysql(); // Starts the databases stuff, etc.
$id = mysql_real_escape_string($_GET['id']);
$game = mysql_query("SELECT * FROM `games` WHERE `id` = $id LIMIT 0, 1");
All he was doing was changing the id parameter, making him able to use SQL injection on my database. I thought mysql_real_escape_string escaped all characters like that, but apparently I was wrong. I did some tests with a normal string to see what would happen, and this is what it said
URL: /game.php?id=' OR '' = '
echo($_GET['id']); // This echo'd: \' OR \'\' = \'
echo(mysql_real_escape_string($_GET['id'])); // This echo'd: \\\' OR \\\'\\\' = \\\'
So, my simple question is, what am I doing wrong?
You need to put the escaped string in single quotes:
WHERE `id` = '$id'
Since id was an integer parameter and you did not surround it in single-quotes in your SQL, the value of $id is sent directly into your query. If you were expecting an integer id, then you should verify that the value of $_GET['id'] is a valid integer.
$id = intval($_GET['id']);
Matt,
mysql_real_escape_string() will only filter for certain characters, if you truly want to prevent injection attacks check out this other Stack Overflow article that suggests you use Prepared statements:
Prepared Statements
PHP Manual entry on Prepared statements
Edit: Also check out Slaks and Michael's postings about wrapping your variable in single quotes.
Good luck!
H
Cast ID. If it is a string it will cast as 0.
$id = (int)$_GET['id'];
Also, MySQL support quotes around both string and numbers in the query.
$game = mysql_query("SELECT * FROM `games` WHERE `id` = '$id' LIMIT 0, 1");
You need to use the parameter binding api. The problem is in this piece of code:
WHERE `id` = $id
You are directly interpolating user input into your SQL statement. That's the open barn door for SQL injection attacks.
You're not using parameterized queries.
MDB2 allows this, though that library may be falling out of favor.
It's very likely that your configuration has magic_quote_gpc, an ancien attempt in PHP to make scripts secure magically. It proved to have multiple flaws and was since deprecated and was scheduled to be completely removed in 5.4 the last time I heard of it.
If you have access to your php.ini configuration, you should disable it. Otherwise, you can modify your script to take it into account and sanitize your input.
All of this is documented here: http://www.php.net/manual/en/security.magicquotes.disabling.php
Otherwise, there is nothing wrong with mysqli_real_escape_string().
You can't prevent SQL injections using mysql_real_escape_string(). It is used for escaping special characters like single quotes ('), double quotes ("), etc.
To prevent SQL injections you have to use PDO statements and filter functions in PHP for sanitizing the user data.
$column = $_GET['id'];
$result = mysql_query("SELECT $column FROM table");
echo $result;
I'm building a website with mysql and am thus trying to learn about sql injections. I assume that this code is vulnerable, but i cant seem to make a working exploit. How would i pull column 'here' from table 'example2'?
Thanks
Imagine $_GET['id'] was equal to something like this
* FROM anytable_i_want; --
the double hypen means the rest of your string is a comment ... so now the sql you're executing is:
SELECT * FROM anytable_i_want;
The single best way to protect from this kind of nonsense is the prepared statement. If you use, say the PDO interface, you do something like this:
$HANDLE = $PDO->prepare('SELECT ? FROM mytable');
$HANDLE->execute(array($_GET['id']));
now no matter what was submitted as $_GET['id'] it woudlnt have any odd effects.
mysql_real_escape_string will cover you if using my mysql_ family of functions, although there is an exploit in the wild that you may be subject to if you change the charset at runtime.
Take a look at PDO and the use of prepared statements to help with preventing SQL injections:
http://net.tutsplus.com/tutorials/php/why-you-should-be-using-phps-pdo-for-database-access/
make $column something like :
" here FROM example2 -- "
if the following text was passed as $_GET['id'], you would have an exploit:
$_GET['id'] = '[other sql commands here]';
use either mysql_real_escape_string() or mysqli_real_escape_string() (if you are using the improved interface)