Web application security

Web application security is the process of protecting websites and online services against different security threats that exploit vulnerabilities in an application’s code. Common targets for web application attacks are content management systems (e.g., WordPress), database administration tools (e.g., phpMyAdmin) and SaaS applications.

Set PHP handler accessPolicy (Request Restrictions) to Read in IIS

Disallow direct access to PHP files in wp-content/uploads/

It’s recommended to disallow access to and execution of PHP files in wp-content/uploads folder. Preferably without the use of a security plugin. Blocking access to PHP files in WordPress wp-content/uploads folder is easily achieved with a .htaccess file on Linux Apache, or web.config accesssPolicy in Windows Server IIS, and here is how.

Security?

WordPress .htaccess security best practices in Apache 2.4.6+

Apache Access Control done right in WordPress .htaccess, ‘Allow/Deny from all’ versus ‘Require All Granted/Denied’. Since Apache 2.4.6, a new module is used to configure and set up access control for websites: mod_authz_core. This means you have to use a different syntax for allowing or blocking hosts and IP addresses to your website. But unfortunately, old documentation is never updated and people even still write blog posts using that old syntax, leaving you with an unprotected website. Not what you had in mind, now is it?

WordPress XMLPRC

Protect WordPress from brute-force XML-RPC attacks

The WordPress XML-RPC API has been under attack for many years. Back in August 2014, WordPress released version 3.9.2, fixing a possible denial of service issue in PHP’s XML processing. There are brute-force amplification attacks, reported by Sucuri, and so on. So, how do you protect WordPress from these xmlrpc.php attacks, optionally still being able to use (some of) its functionality like Jetpack? This post gives you some insights.

brown wooden blocks on white surface

Check WordPress Core files integrity

Check and verify WordPress Core files md5 checksums against WordPress’ checksums API, using this standalone PHP file. WordPress integrity matters, therefore I chose to use a standalone PHP script to check the md5sum of WordPress Core files against the API so you’re not dependent on a possibly hacked WordPress installation. This kind of guarantees the result can be trusted, as opposed to using a WordPress plugin. I think this is a better integrity check of WordPress Core files.

“How we broke PHP, hacked Pornhub and earned $20,000”

This is a very interesting read on how Dario Weißer (@haxonaut), cutz and Ruslan Habalov (@evonide) were able to find a PHP unserialize bug to exploit and gain remote code execution on Pornhub. Pornhub’s bug bounty program is at Hackerone. Instead of actively attacking Pornhub, they took another road and attacked what Pornhub is built upon: PHP.

Cracking PHP rand()

Webapps occasionaly need to create tokens that are hard to guess. For example for session tokens or CSRF tokens, or in forgot password functionality where you get a token mailed to reset your password. These tokens should be cryptographically secure, but are often made by calling rand() multiple times and transforming the output to a string. This post will explore how hard it is to predict a token made with rand().

Add a delay to your WordPress login form

This plugin adds a three second delay when logging into WordPress. This slows down brute-force attacks on your website. However, it is not recommended to use sleep(), because a heavy brute-force attack will let all those POST requests sleep for the given amount of time.

Increase in SQL injection attacks

Since a week or so, I notice a huge increase in SQL injection attacks on various websites. Anyone else seeing the same SQL injection attacks lately? This increased SQL injection activity – on various web sites and databases – has the following characteristics

Test SMTP Authentication and StartTLS

When investigating SMTP authentication issues, particular over TLS encrypted SMTP connections, it’s always handy if you are able to test the SMTP authentication and StartTLS connection. Preferably from your command line. This post shows you how to test SMTP servers, create base64 encoded logon information, verify SMTP authentication over an opportunistic TLS connection, all from the Linux and Windows command line.