mysql

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Nginx, SSL & php5-fpm on Debian Wheezy

I decided to take a break from my love affair with Apache and set up a recent development project on Nginx. I’ve seen nothing but good things in terms of speed and performance from Nginx. I decided to set up a LEMP server (Linux, Nginx, MySQL, PHP), minus the MySQL as it’s already installed on my VM host server, and plus SSL. Here’s the full setup tutorial on Debian Wheezy: Step #1 – Installing the packages apt-get install nginx-extras mysql-client apt-get install php5-fpm php5-gd php5-mysql php-apc php-pear php5-cli php5-common php5-curl php5-mcrypt php5-cgi php5-memcached MySQL can be installed into the mix with a simple: apt-get install mysql-server […]

By | October 11th, 2014|Development, Hosting, Linux, MySQL, MySQL, PHP, PHP, PHP Articles, VPS|0 Comments

MySQL Master-Master Replication, Heartbeat, DRBD, Apache, PHP, Varnish MegaHOWTO

I created this HOWTO while building a new development environment today. The intention is to take a single Apache2/Varnish/MySQL environment and scale it to two servers, with one effectively a “hot-standby” – increase redundancy and continuity whilst maintaining current performance. This HOWTO is based on Linux Debian-76-wheezy-64-minimal 3.2.0-4-amd64 #1 SMP Debian 3.2.60-1+deb7u3 x86_64 Our current server has IP 192.168.201.1/24 and our new server has IP 192.168.201.7. Section #1: Set up MySQL Master/Master Replication First, we’ll set up MySQL master to master replication. In this configuration, data can be written and read from either host. Bear in mind that issues may exist with autoincrement fields when written to at the same time. There are other caveats with replication so ensure to research them along with how to deal with corruption and repair before considering this setup for a live application. Also be sure to be using the same version of MySQL on both servers – this may not always be necessary, however unless you are very familiar with any changes between versions, not doing so could spell disaster. […]

SQL injection with sqlmap

sqlmap is web application & database penetration testing tool that automates detecting and exploiting many types of SQL injection flaw, and then taking over the database server. It’s able to detect a huge range of injection types. Let’s take the following code – <?php $link = mysql_connect("localhost", "twl", "XXXX"); mysql_select_db("twl"); echo "This is a page\n"; $sql = "SELECT * FROM wp_posts WHERE ID=’" . $_GET[‘id’] . "’;"; $res = mysql_query($sql); mysql_free_result($res); echo "This is some text\n"; mysql_close($link); ?> […]

By | December 10th, 2013|Security Consultant|0 Comments

mysql_real_escape_string won’t magically solve your SQL Injection problems

Edited: 5th Oct 2014 after bug fixing and reader feedback Edited: 6th Oct 2014 after reader feedback I was engaged by an online retailer to test their custom web application CMS and store. I attended their premises and sat down with the tech manager and his lead developer to discuss with them from both a business management and a technical perspective some of the vulnerabilities that should be tested for, as well as to gain a solid understanding of the business needs and logic. When I came on to SQL injection, I was assured by the lead developer that owing to their secure coding practices, SQL injection is completely impossible. All expected user entered integers are cast as integers, and all expected user entered strings are run through mysql_real_escape_string before being passed back to the database. Once code is committed by a developer to the development Subversion server, the lead developer then manually reviews it before deciding to push it live. Great, I thought, it’s certainly a good start. I did point out that this might not always work, but he didn’t seem too phased, and I didn’t want to get too much into a discussion about why or when that might not always work at that stage. […]

By | August 18th, 2013|MySQL, PHP, Security Consultant|13 Comments

MySQL Root to System Root with lib_mysqludf_sys for Windows and Linux

Once a MySQL database server has been compromised at root level, it’s often possible to escalate this access to full system level access using User Defined Functions (UDFs). We may have MySQL root access but not system root access for a number of reasons including having a shell account on the target whilst MySQL’s root user has been left unpassworded by default, or alternatively gaining access via SQL injection through a web application connecting to the database as root, which is something I see far too often. Firstly, you’ll want to check out a copy of sqlmap. For this attack you’ll want to browse to the ‘udf’ directory and select the appropriate library depending on your target platform: udf/mysql/linux/32/lib_mysqludf_sys.so udf/mysql/linux/64/lib_mysqludf_sys.so udf/mysql/windows/32/lib_mysqludf_sys.dll udf/mysql/windows/64/lib_mysqludf_sys.dll The steps for escalation on both Windows and Linux are the same. Firstly, we need to get a copy of the correct library on to the target machine in a known location – this could be by uploading to a user account we have access to, or uploading via a website image/file upload, or anonymous FTP account. The second step is issuing a SQL query to load this file in to a newly created table row. Third, we then want to dump that table row out to a new file in either the ‘/usr/lib’ directory or the ‘c:\windows\system32’ directory depending on whether we are on Linux or Windows respectively. The reason we need to do this, is that our regular web application or user account does not have permission to create files in these directories, however the MySQL root user does. Next, we want to instruct MySQL to create a new function to point to the code in our malicious library. Lastly, we execute this new function with arbitrary system commands that we wish to run. […]

By | August 13th, 2013|MySQL, Security Consultant|8 Comments

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: […]

By | June 24th, 2010|Development, MySQL, PHP, PHP, PHP Articles, Technology|0 Comments

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 over, why not consider some of the things that can be done to help prevent a website breach.. […]

By | January 19th, 2010|Development, Linux, MySQL, PHP, Security Consultant, Technology|1 Comment

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. […]

By | January 14th, 2010|Development, PHP, PHP, PHP Articles, Technology|0 Comments

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. […]

By | November 15th, 2009|Development, PHP, PHP, PHP Articles|0 Comments