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The Perishable Press 4G Blacklist

At last! After many months of collecting data, crafting directives, and testing results, I am thrilled to announce the release of the 4G Blacklist! The 4G Blacklist is a next-generation protective firewall that secures your website against a wide range of malicious activity. Like its 3G predecessor, the 4G Blacklist is designed for use on Apache servers and is easily implemented via HTAccess or the httpd.conf configuration file. In order to function properly, the 4G Blacklist requires two specific Apache modules, mod_rewrite and mod_alias. As with the third generation of the blacklist, the 4G Blacklist consists of multiple parts: Update […] Read more »

Building the Perishable Press 4G Blacklist

Last year, after much research and discussion, I built a concise, lightweight security strategy for Apache-powered websites. Prior to the development of this strategy, I relied on several extensive blacklists to protect my sites against malicious user agents and IP addresses. Unfortunately, these mega-lists eventually became unmanageable and ineffective. As increasing numbers of attacks hit my server, I began developing new techniques for defending against external threats. This work soon culminated in the release of a “next-generation” blacklist that works by targeting common elements of decentralized server attacks. Consisting of a mere 37 lines, this “2G” Blacklist provided enough protection […] Read more »

Controlling Proxy Access with HTAccess

In my recent article on blocking proxy servers, I explain how to use HTAccess to deny site access to a wide range of proxy servers. The method works great, but some readers want to know how to allow access for specific proxy servers while denying access to as many other proxies as possible. Fortunately, the solution is as simple as adding a few lines to my original proxy-blocking method. Specifically, we may allow any requests coming from our whitelist of proxy servers by testing Apache’s HTTP_REFERER variable, like so: RewriteCond %{HTTP_REFERER} !(.*)allowed-proxy-01.domain.tld(.*) RewriteCond %{HTTP_REFERER} !(.*)allowed-proxy-02.domain.tld(.*) RewriteCond %{HTTP_REFERER} !(.*)allowed-proxy-03.domain.tld(.*) Read more »

Eight Ways to Blacklist with Apache’s mod_rewrite

With the imminent release of the next series of (4G) blacklist articles here at Perishable Press, now is the perfect time to examine eight of the most commonly employed blacklisting methods achieved with Apache’s incredible rewrite module, mod_rewrite. In addition to facilitating site security, the techniques presented in this article will improve your understanding of the different rewrite methods available with mod_rewrite. Blacklist via Request Method This first blacklisting method evaluates the client’s request method. Every time a client attempts to connect to your server, it sends a message indicating the type of connection it wishes to make. There are […] Read more »

PHP Short Open Tag: Convenient Shortcut or Short Changing Security?

Most of us learned how to use “echo()” in one of our very first PHP tutorials. That was certainly the case for me. As a consequence, I never really had a need to visit PHP’s documentation page for echo(). On a recent visit to Perishable Press, I saw a Tumblr post from Jeff about the use of PHP’s shortcut syntax for echo() but somewhere deep in my memory, there lurked a warning about its use. I decided to investigate. Read more »

Redirect All (Broken) Links from any Domain via HTAccess

Here’s the scene: you have been noticing a large number of 404 requests coming from a particular domain. You check it out and realize that the domain in question has a number of misdirected links to your site. The links may resemble legitimate URLs, but because of typographical errors, markup errors, or outdated references, they are broken, leading to nowhere on your site and producing a nice 404 error for every request. Ugh. Or, another painful scenario would be a single broken link on a highly popular site. For example, you may have one of your best posts mentioned in […] Read more »

Redirect WordPress Individual Category Feeds to Feedburner via HTAccess

Time for another Feedburner redirect tutorial! In our previous FeedBurner-redirect post, I provide an improved HTAccess method for redirecting your site’s main feed and comment feed to their respective Feedburner URLs. In this tutorial, we are redirecting individual WordPress category feeds to their respective FeedBurner URLs. We will also look at the complete code required to redirect all of the above: the main feed, comments feed, and of course any number of individual category feeds. Let’s jump into it.. Read more »

Better Default Directory Views with HTAccess

Beautify your default directory listings! Displaying index-less file views is a great way to share files, but the drab, bare-bones interface is difficult to integrate into existing designs. While there are many scripts available to customize the appearance and functionality of default directory navigation, most of these methods are either too complicated, too invasive, or otherwise insufficient for expedient directory styling. In this comprehensive tutorial, you will learn how to use the built-in functionality of Apache’s mod_autoindex module to style and enhance your default directory views with a smorgasbord of stylistic and functional improvements. Read more »

Blacklist Candidate 2008-10-19

Welcome to the Perishable Press “Blacklist Candidate” series. In this post, we continue our new tradition of exposing, humiliating and banishing spammers, crackers and other worthless scumbags.. From time to time on the show, a contestant places a bid that is so absurd and so asinine that you literally laugh out loud, point at the monitor, and openly ridicule the pathetic loser. On such occasions, even the host of the show will laugh and mock the idiocy. Of course, this same situation happens frequently here at Perishable Press, where the scumbags that manage to escape the 3G Blacklist are proving […] Read more »

WordPress Feedburner HTAccess Redirect for Default (Non-Permalink) Feed URLs

Recently, a client wanted to deliver her blog feed through Feedburner to take advantage of its excellent statistical features. Establishing a Feedburner-delivered feed requires three things: a valid feed URL, a Feedburner account, and a redirect method. For permalink-enabled WordPress feed URLs, configuring the required redirect is straightforward: either install the Feedburner Feedsmith plugin or use an optimized HTAccess technique. Unfortunately, for sites without permalinks enabled, the Feedsmith plugin is effectively useless, and virtually all of the HTAccess methods currently available on the Web are designed for permalink-enabled configurations. In this article, we will modify our existing HTAccess technique to […] Read more »

Redirecting Subdirectories to the Root Directory via HTAccess

One of the most useful techniques in my HTAccess toolbox involves URL redirection using Apache’s RedirectMatch directive. With RedirectMatch, you get the powerful regex pattern matching available in the mod_alias module combined with the simplicity and effectiveness of the Redirect directive. This hybrid functionality makes RedirectMatch the ideal method for highly specific redirection. In this tutorial, we will explore the application of RedirectMatch as it applies to one of the most difficult redirect scenarios: redirecting all requests for a specific subdirectory (or any subordinate directory or file) to the root (or any parent) directory. We will explore how to accomplish […] Read more »

IE6 Support Spectrum

I know, I know, not another post about IE6! I actually typed this up a couple of weeks ago while immersed in my site redesign project. I had recently decided that I would no longer support that terrible browser, and this tangential post just kind of “fell out.” I wasn’t sure whether or not to post it, but I recently decided to purge my draft stash by posting everything for your reading pleasure. Thus, you may see a few turds in the next few weeks, but hopefully this isn’t one of them. In any case, here is my final post […] Read more »

Blacklist Candidate Series Summary

An ongoing series of articles on the fine art of malicious exploit detection and prevention. Learn about preventing the sneaky mischievous and deceptive practices of some of the worst spammers, scrapers, crackers, and other scumbags on the Internet. Read more »

Evil Incarnate, but Easily Blocked

As my readers know, I spend a lot of time digging through error logs, preventing attacks, and reporting results. Occasionally, some moron will pull a stunt that deserves exposure, public humiliation, and banishment. There is certainly no lack of this type of nonsense, as many of you are well-aware. 3G Blacklist Even so, I have to admit that I am very happy with my latest strategy against crackers, spammers, and other scumbags, namely, the 3G Blacklist. Since implementing this effective HTAccess security method, I have seen a dramatic decrease in the overall volume of malicious activity recorded in my Apache, […] Read more »

Redirect All Requests for a Nonexistent File to the Actual File

In my previous article on redirecting 404 requests for favicon files, I presented an HTAccess technique for redirecting all requests for nonexistent favicon.ico files to the actual file located in the site’s web-accessible root directory: # REDIRECT FAVICONZ <ifmodule mod_rewrite.c> RewriteCond %{THE_REQUEST} favicon.ico [NC] RewriteRule (.*) http://domain.tld/favicon.ico [R=301,L] </ifmodule> As discussed in the article, this code is already in effect here at Perishable Press, as may be seen by clicking on any of the following links: Update 2015/09/03: I’ve removed the favicon redirect on this site in order to account for vastly more complicated favicon requirements (e.g., android, apple, avatar, […] Read more »

Stop the Madness: Redirect those Ridiculous Favicon 404 Requests

For the last several months, I have been seeing an increasing number of 404 errors requesting “favicon.ico” appended onto various URLs: When these errors first began appearing in the logs several months ago, I didn’t think too much of it — “just another idiot who can’t find my site’s favicon..” As time went on, however, the frequency and variety of these misdirected requests continued to increase. A bit frustrating perhaps, but not serious enough to justify immediate action. After all, what’s the worst that can happen? The idiot might actually find the blasted thing? Wouldn’t […] Read more »

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