Examples of Nested Encoding

Typically malicious scans use some sort of encoding to obscure their payloads. For example, instead of injecting a literal script, the attacker will run it through a PHP encoding function such as base64_encode(), utf8_encode(), or urlencode(). So if and when you need to decode some discovered payload, you can use whichever decoding function will do the job. For example, base64_decode(), utf8_decode(), or urldecode(). Sounds straightforward, but let’s dig a little deeper.. Continue reading »

.htaccess Cleanup

Once again I am cleaning up my sites’ .htaccess files. I do this from time to time to remove old redirects, refresh blacklists, and update security and SEO-related directives. It’s tedious work, but the performance and security benefits make it all worthwhile. This post shares some of the techniques that were added, removed, or replaced from .htaccess, and explains the reasoning behind each decision. I do this for the sake of reference, and hopefully it will give you some ideas […] Continue reading »

Tools to check your site’s health

Perishable Press is now over 12 years old. It is a lot of work keeping everything updated, maintained, and well-secured. Fortunately there are a gazillion free online tools for checking your site’s health. Everyone has their favorites. In this quick article, I share mine. Continue reading »

Lynda.com Course: Developing Secure WordPress Sites

[ WordPress: Developing Secure WordPress Sites ]

After months of preparation and production, my new video course on developing secure WordPress sites is now available at Lynda.com. This is my second video course on securing WordPress; the first one was originally launched in 2011 and remained in Lynda’s library for over five years. I received a lot of great feedback on the course, and so I jumped on the opportunity to do another one. If there is one thing that I enjoy doing, it’s helping people with […] Continue reading »

Stop User Enumeration in WordPress

This tutorial explains how to block user-enumeration scans in WordPress. As explained in greater depth here, user enumeration happens when some malicious script scans a WordPress site for user data by requesting numerical user IDs. For example, requests for author=1 through some number, say, author=1000, may reveal the usernames for all associated users. With a simple enumeration script, an attacker can scan your site and obtain a list of login names in a matter of seconds. Continue reading »

Stop RSSing.com from Framing Your Content

[ RSSing.com Removal Request or Whatever ]

This quick post explains how to stop the notorious site scrapers, RSSing.com, from stealing your content. In fact, this technique can be used to stop virtually any site that uses HTML frames to scrape your pages. Once again, the solution is one line of .htaccess to the rescue. Continue reading »

Use Strong Usernames for Better Security

Image courtesy of eChunks.com Here is a quick security tip for people using popular apps on the Web. That is, apps like WordPress that may be widely used and targeted by bad actors and/or automated scripts. It’s all about adding another layer of security by hardening admin-level usernames.. Every now and then, I get an email letting me know that someone has requested a password reset for one of my admin-level WordPress accounts. Usually, the email notifications are sent directly […] Continue reading »

WordPress Plugin: Blackhole for Bad Bots

Image Courtesy NASA/JPL-Caltech. Update: Pro version now available! Check out Blackhole Pro » Finally translated my Blackhole Spider Trap into a FREE WordPress plugin. It’s fun, fast, flexible, and works silently behind the scenes to protect your WordPress-powered site from malicious bots. Here are some of the features: Continue reading »

What to do when your site gets hacked

Over the years, my sites have been hacked numerous times. Each hacking event was somewhat of a miserable experience at first, but ultimately educational and even enlightening. I’m not going to say that getting hacked was the best thing that ever happened to me, but it certainly wasn’t the end of the world. In this post, I want to share some important steps to take and things to keep in mind if and when you discover that your site has […] Continue reading »

Block revslider Scans

One of the most annoying, persistent scans I’ve seen in a long time are those hunting for the revslider vulnerability. In the five or so months since the exploit was discovered, many sites have been compromised. And based on what I’ve been seeing in my traffic logs, the risk is far from over. Apparently every 2-bit script kiddie and their pet hamster wants a piece of the “revslider action”. Continue reading »

Protect Against Malicious POST Requests

Whether you like it or not, there are scripts and bots out there hammering away at your sites with endless HTTP “POST” requests. POST requests are sort of the opposite of GET requests. Instead of getting some resource or file from the server, data is being posted or sent to it. To illustrate, normal surfing around the Web involves your browser making series of GET requests for all the resources required for each web page. HTML, JavaScript, CSS, images, et […] Continue reading »

2014 Micro Blacklist

Over the past several months, I’ve assembled a “micro” blacklist to keep some recent threats at bay. Eventually, this will be integrated into the next nG Blacklist, but for now I just wanted to post and share with anyone else who is actively monitoring their server logs and aware of the recent spike in malicious activity. Continue reading »

2013 User Agent Blacklist

The 2013 User Agent Blacklist blocks hundreds of the worst bots while ensuring open-access for normal traffic, major search engines (Google, Bing, et al), good browsers (Chrome, Firefox, Opera, et al), and everyone else. Compared to blocking threats by IP, blocking by user-agent is more effective as a general security strategy. Although it’s trivial to spoof any user agent, many bad requests continue to report user-agent strings that are known to be associated with malicious activity. For example, the notorious […] Continue reading »

(Please) Stop Using Unsafe Characters in URLs

Just as there are specifications for designing with CSS, HTML, and JavaScript, there are specifications for working with URIs/URLs. The Internet Engineering Task Force (IETF) clearly defines these specifications in RFC 3986: Uniform Resource Identifier (URI): Generic Syntax. Within that document, there are guidelines regarding which characters may be used safely within URIs. This post summarizes the information, and encourages developers to understand and implement accordingly. Continue reading »

expose_php, Easter Eggs, and .htaccess

A reader recently brought to my attention a reported vulnerability on servers running PHP. It’s been known about for eons, but it’s new to me and it involves easter eggs in PHP so I thought it would be fun to share a quick post about what it is and how to prevent leakage of sensitive information about your server. It only takes a moment to disable the easter-egg information, should you decide to do so. Continue reading »

10 Characters for Your WordPress Blacklist

[ Screenshot: Comment Spam in Moderation ]

Quick WordPress tip for easily and quietly blocking a ton of comment spam. Akismet and other programs are good at catching most spam, but every now and then a bunch of weird, foreign-language spam will sneak past the filters and post live to your site. Here’s a good example of the kind of stuff that’s easy to block: Continue reading »

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