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Configuring and Administering Your Server >>
Identifying a Compromised Script Sending Spam from Your Server
"For people who make websites" - A List Apart Magazine explores the design, development, and meaning of web content, with a special focus on web standards and best practices.
HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla. The number of errors of a HTML page is seen in the form of an icon in the status bar when browsing. The details of the errors are seen when looking the HTML source of the page.
The extension is based on Tidy and OpenSP. Both algorithms were originally developed by the Web Consortium W3C. Both algorithms are embedded inside Mozilla/Firefox and makes the validation locally on your machine, without sending HTML to a third party server.
The extension is based on Tidy and OpenSP. Both algorithms were originally developed by the Web Consortium W3C. Both algorithms are embedded inside Mozilla/Firefox and makes the validation locally on your machine, without sending HTML to a third party server.
This project aims to create an archive of user contributed clip art that can be freely used.
Starting at the beginning, this reference explains everything you need to know about using core JavaScript. It assumes you have the following basic background: a general understanding of the Internet and the World Wide Web and a good working knowledge of HTML. An excellent resource.
Edit your images on the fly online with Splashup, a web-based image editor that integrates with Flickr, Facebook, and Picasa. Splashup offers up a surprising array of image editing tools, far beyond the usual crop of resize and contrast-- you can also edit multiple images, play with filters and layers, use a variety of brushes, and more. Splashup is one of the best image editors in a long line of image editors; i.e., Picnik, Pixoh, and Resizr, to name just a few.[Lifehacker Annotation]
This website will let you:
- Create an XML sitemap format that can be submitted to Google to help them crawl your website better.
- Create a Text sitemap to submit to Yahoo.
- Create a ROR sitemap, which is an independant XML format for any search engine.
- Generate an HTML site map to allow human visitors to easily navigate on your site.
Clearspring's free Launchpad widget builder lets you easily turn your website's content into a widget which site visitors can use to place your content on all the major social media sites (MySpace, FaceBook, Google, hi5, Live, Yahoo, Wordpress, Blogger, etc.). The service also provides tracking and analysis.
This site features online text and html changing, modifying, converting tools designed to save you time making web pages or preparing text for web publication. If you've ever needed to capitalize sentences or convert line breaks to <p> or <br /> then this site can save you needless manual labor. There are other useful tools as well, like the one to uncompress html to make it readable and the ones to uppercase or lowercase text. Basically, the most common tasks that someone who works in an office or does freelance web development might encounter. Most of the tools have been created using javascript so you should be able to change large amounts of text as the processing is done on your computer instead of being limited by a server script.
You've downloaded and configured your Apache server and are ready to move on to the next project. Can it really be left to fend for itself in a darkened room?
Yes. To some degree, anyway. On the other hand, completely ignoring your Apache installation would be foolhardy.
Yes. To some degree, anyway. On the other hand, completely ignoring your Apache installation would be foolhardy.
The Wikipedia entry for Sender Policy Framework (SPF).
The Wikipedia entry for DomainKeys.
Useful Resources
View all resources
Editor Favorites
- A List Apart
- HTML Validator Firefox Plugin
- Open Clip Art Library
- Core JavaScript Guide: Version 1.5
- Splashup
- XML Sitemaps Generator
- Clearspring Launchpad
- Text Fixer
Other Resources
Links to Consider
When you use third party software programs, both open source and commercial, there is an increased possibility that they will have security flaws which are exploited. This is true because the programs are well-known, often make the source code publicly available, and because hackers realize that security holes in these programs will exist on a lot of servers.
Recently, I noticed that one of my servers was sending spam emails. I knew this because I was getting mailer daemon notifications of failed emails. Now, these types of email are so common they are easy to overlook. But, in this case, the mailer daemon sending the notices was my own server so I decided to investigate. Sure enough, there was a real problem. But, the question was how I could find the cause. I think most people would say that you should investigate the server logs and I am sure that would be smart, but I wasn't really sure what to look for or where. When I contacted my hosting company for some help, they were able to determine that the server didn't appear to be hacked and that the emails were probably being sent from a PHP script using the mail function. They also referred me to a very useful article which offers a method of determining which directory is sending the emails. It does this by adding an extra X-Mailer header (an informational header field in emails) and it also writes all email activity from PHP scripts to a log file.
The process is pretty simple. First, you create a "wrapper" shell script which will add the additional X-Mailer header. Note that at first I had a problem because I created this file on my PC and then FTP'd it to the server and it contained a carriage return symbol that isn't supported on *nix systems. Just be careful to save your file in *nix format or create the file directly on your server.
The second step is to create a log file to save the header information of the emails with this extra X-Mailer header. You will then run a couple of symbolic links to append the wrapper script to the regular sendmail (or qmail) program. You let it run in this mode long enough to generate some of the problem spam emails and then you undo the process and investigate the results.
Of course, once you know what folder is being used to send the offending emails, you still have to investigate the manner in which the script was compromised, but clearly that is much easier to do when you actually know what script is causing the problems.
Recently, I noticed that one of my servers was sending spam emails. I knew this because I was getting mailer daemon notifications of failed emails. Now, these types of email are so common they are easy to overlook. But, in this case, the mailer daemon sending the notices was my own server so I decided to investigate. Sure enough, there was a real problem. But, the question was how I could find the cause. I think most people would say that you should investigate the server logs and I am sure that would be smart, but I wasn't really sure what to look for or where. When I contacted my hosting company for some help, they were able to determine that the server didn't appear to be hacked and that the emails were probably being sent from a PHP script using the mail function. They also referred me to a very useful article which offers a method of determining which directory is sending the emails. It does this by adding an extra X-Mailer header (an informational header field in emails) and it also writes all email activity from PHP scripts to a log file.
The process is pretty simple. First, you create a "wrapper" shell script which will add the additional X-Mailer header. Note that at first I had a problem because I created this file on my PC and then FTP'd it to the server and it contained a carriage return symbol that isn't supported on *nix systems. Just be careful to save your file in *nix format or create the file directly on your server.
The second step is to create a log file to save the header information of the emails with this extra X-Mailer header. You will then run a couple of symbolic links to append the wrapper script to the regular sendmail (or qmail) program. You let it run in this mode long enough to generate some of the problem spam emails and then you undo the process and investigate the results.
Of course, once you know what folder is being used to send the offending emails, you still have to investigate the manner in which the script was compromised, but clearly that is much easier to do when you actually know what script is causing the problems.
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