14 Jul 10 Securing PHPMyAdmin and SQL

PHP is of course a valuable tool, and PHPMyAdmin is an equally valuable asset for those that don’t like command line administration. The problem is that because it’s a valuable tool, it’s a security exposure. As a website security consultant, I see the problem often: people don’t secure the one thing that, if accessed by a malicious party, can give carte blanche for destruction.

One simple way to secure your installation is to slightly modify your config.inc.php file:

Look for this line:

$cfg['Servers'][$i]['auth_type'] = ‘config’;

Change “config” to “http”. By doing this, you will require that the database information (username and password) be entered prior to accessing PHPMyAdmin. Of course, this only addresses attacks over the web. If someone tries to remotely connect to your database and knows the root password, or the credentials for any of your database, then you’re still vulnerable.

One way to address the security of your config.inc.php file is to secure the directory that it’s stored in. This is especially important if you should be on a shared server.

Of course, there is still the matter of your SQL port, 3306, being open to remote attacks. The solution to this problem can be found in the /etc/my.cnf file.

You need to add this line to make it so that only your server can connect to the SQL server.

Ensure that it’s under the “[mysqld]” section:

bind-address = 127.0.0.1

This sets it so that the SQL daemon only listens for connections locally, i.e. on your server. Anyone who tries to connect remotely will be denied. Now, the argument could be made that you could also try to add “skip-networking” to your my.cnf file, and then specify the path to your socket file, but you still need a way to administer your SQL, preferably via SSH. By adding the “bind-address” command, you can do just that.

The name of the game is security, and assumption. You have to assume that everyone’s out to attack you. If you think like that, you’ll narrow down all the ports that are exposed, and secure your server. Your SQL server is, like your DNS server, vital. It most likely powers your site. If the database is attacked, the damage can be considerable. Do understand that if a hacker is intent enough, they will find a way in, but by making it as difficult as possible, you reduce the chances of that happening.

Tags: attacks, MySQL, PHP, php programmer resume, phpmyadmin, sql, website security consultant

25 Jun 10 MySQL – Find Duplicates Only

Within MySQL, we may want to select duplicate records, instead of just selecting unique records. Assuming a table name of ‘table’ and the field to check on being ‘field’;

To select UNIQUE rows only:
SELECT DISTINCT field FROM table;

To select DUPLICATE rows only:
SELECT field FROM table GROUP BY field HAVING ( COUNT(field) = 2 )

To select DUPLICATE, TRIPLICATE or more rows only:
SELECT field FROM table GROUP BY field HAVING ( COUNT(field) > 1 )

Tags: distinct, duplicate, having, MySQL, select, unique

24 Jun 10 PHP, MySQL and memcached

According to memcached is a distributed object memory caching system. It can be used to set and get data by keys by any application that supports sockets.

As a website security consultant I advise you to ensure that your memcache server runs on 127.0.0.1 only and that you secure your server. Anyone with access to the server can telnet to the server’s local interface and get/set your memcache data.

I’ve used memcached for a number of PHP/MySQL projects, where I want greater cache control on database queries, than just relying on MySQL’s inbuilt caching abilities.

Now, whilst memcached should not be used to mask bad database design and optimization, or badly written SQL queries, it can help dramatically with queries that simply take a long time and have already been optimized as far as possible.

Assume that you had a simple database query wrapper:
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Tags: memcache, memcached, MySQL, PHP

06 Jun 10 MySQL – Running Processes

Showing running processes is easy, just log in to the MySQL command line and issue ‘SHOW PROCESSLIST;’
mysql> SHOW PROCESSLIST;
+———-+——+————————-+————+———+——+———-+———————————————————————————————–+
| Id | User | Host | db | Command | Time | State | Info |
+———-+——+————————-+————+———+——+———-+———————————————————————————————–+
| 66041116 | root | localhost | NULL | Query | 0 | NULL | SHOW PROCESSLIST |
| 66042322 | sql | www.adamsinfo.com:57281 | websonline | Query | 1 | Updating | UPDATE `video_tags` SET `quantity` = ’27′ WHERE CONVERT( `tag` USING utf8 ) = ‘sport’ LIMIT 1 |
+———-+——+————————-+————+———+——+———-+———————————————————————————————–+
2 rows in set (0.00 sec)

You can also use 'SHOW' to display a wide range of information: http://dev.mysql.com/doc/refman/5.0/en/show.html

Tags: MySQL, processes, processlist, show

20 Apr 10 Access denied for user ‘debian-sys-maint’@'localhost’

Exporting all databases from a MySQL installation on Debian using –all-databases, and then importing them back into a new installation will overwrite your privileges table. Whilst this may be what you want, each MySQL installation on debian generates a unique /etc/mysql/debian.cnf which contains logon details for the ‘debian-sys-maint’ system account. This account is used by the custom Debian scripts to deal with things such as checking for crashed tables.

After your export and import, you will likely end up with an error on your new installation:

‘Access denied for user ‘debian-sys-maint’@'localhost’

The way to fix this, is to log in to MySQL as root, and issue:

GRANT ALL PRIVILEGES ON *.* TO ‘debian-sys-maint’@'localhost’ IDENTIFIED BY ‘xxxxx’ WITH GRANT OPTION

Where ‘xxxxx’ is the password found in your debian.cnf file.

Then issue: FLUSH PRIVILEGES; and restart MySQL

Tags: MySQL

19 Jan 10 Website Security Scan

Websites get hacked every day, customers details taken, and it’s usually REALLY EASY to do. As a security consultant,  I often get a call after a Google search turns up with my details as the guy to contact when this happens.

Shameless plug: Why not contact me BEFORE this happens for a FREE basic web scan.

Shameless plug over, why not consider some of the things that can be done to help prevent a website breach..
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Tags: Apache, backups, code, cookie, cross site scripting, htaccess, LAMP, logs, mod_security, MySQL, PHP, php security, rate limit, restrict limit, Security Consultant, session, sniffing, sql injection, website security scan, xss

14 Jan 10 PHP Security

As a PHP programmer, there are a couple of things you can do quickly and easily to increase the security of your PHP code installation.

Look into PHP’s “safe mode” feature, ESPECIALLY if you’re running a webserver that takes the general public can upload scripts to. Here you’ll find a list of the functions disabled or restricted by safe mode. It is not strictly PHP’s job to restrict these types of functions, however unless you really know what you’re doing, the list of functions restricted by safemode is a good starting point for building secure applications. These are generally functions that allow file and directory manipulation, and socket manipulation. If it’s not possible within your environment to disable them all, disable as many of these functions as possible.

Although not that common, if I’m writing an application that heavily relies on functions that manipulate directories or sockets, I’ll prefer to create a C daemon or similar to handle this side of things and simply use PHP to communicate with it. (more…)

Tags: cross site scripting, directory, error reporting, magic quotes, MySQL, mysql_real_escape_string, PHP, php security, safe mode, socket, sql injection, xss

15 Nov 09 PHP Developer – Loops in General

There are 3 types of loop in PHP:

while (condition)
{ code_goes_here; }

do
{ code_goes_here; }
while (condition);

for(expr1, expr2, expr3)
{ code_goes_here; }

In terms of the ‘for’ loop above, ‘expr1′ being the starting expression, i.e. $i=0. expr2 being the condition that must be satisfied to keep the loop running, i.e. $i < 100. expr3 being the expression evaluated each time the loop runs, i.e. $i++. Each loop type has it’s uses.
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Tags: do, for, loop, MySQL, PHP, PHP Developer, PHP MySQL Developer

05 Nov 09 PHP Developer – Looping through database results

As a PHP Programmer, a very routine PHP/MySQL procedure is fetching a set of records from the result of a query.

$sql = "SELECT ...";
$result_set = mysql_query($sql);
for ($ctr = 0; $ctr < mysql_numrows($result_set); $ctr++)
{
    $my_object = mysql_fetch_object($result_set);
    //do something with $my_object
}

Now as tidy as the above code is, what’s the big problem? The number of rows returned by the query remains the same throughout. Why are we calling the mysql_numrows function on the same result set, to return the same answer over and over, possibly thousands of millions of times depending on the size of the result set? On a larger web application with a larger result set, things like this will dramatically increase unnecessary overhead. This is one of the most basic optimizations to make:

$sql = "SELECT ...";
$result_set = mysql_query($sql);
$result_num = mysql_numrows($result_set);
for ($ctr = 0; $ctr < $result_num; $ctr++)
{
    $my_object = mysql_fetch_object($result_set);
    //do something with $my_object
}

Now, there’s a couple of different methods you can use to achieve the same purpose, some of which may actually be more appropriate, such as a simple while loop, but the purpose of this article was to illustrate the issue above solely. More on optimization later..

Tags: for, loop, MySQL, PHP, php programmer, sql

26 Sep 09 PHP MySQL Developer – A Freelancer in London

Being a Freelance PHP MySQL Application Developer based in London has some major advantages as I found out today. The majority of both mine and my firm’s work is conducted online. Video conferencing over Skype, code delivery over SVN (Subversion), and bug tracking through Basecamp. Once in a while though an opportunity for a site visit in or around central London/West End pops up, and, schedule permitting, I’ll more often than not be happy to accept.

My core focus is on web application development, and being London based, I’ve had a chance to work with some great Companies. I’m currently at the time of writing, spending a few hours per week overseeing and managing a team of developers rewriting a wireless hotspot provider’s intranet which is proving to be very challenging, and great fun.

For more information on what it is that I actually do in the PHP/MySQL field, please view my PHP MySQL Developer series!

Tags: MySQL, PHP, php mysql, PHP MySQL Developer, php mysql developer london