Linux servers can now be infected - Or can they ?

Linux gurus have always vouched on the safety and security of Linux - especially Linux running as servers. However, now after a developer named Denis Sinegubko has published his findings, they may just have to ponder over their words.

According to Denis, the Linux servers can be infected to be used in a botnet used to distribute malware.  The modus operandi of attack is as follows :
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online htaccess editor

If you have ever configured the apache web server, then you will realize the important part played by the .htaccess file. This file is especially used by people who make use of a shared web host provider to host their sites.

Some of the uses of .htaccess file that I can think of are :

• Redirecting the visitor automatically to the new location of the web page.
• Providing a 301 redirect [moved permanently] to search engine spiders.
• Setting up a username and password to access a part of or whole of your website.
• Restricting access to your website for all visitors originating from a particular IP address or IP range.
  

... and so on and so forth.

I have always found editing the .htaccess file as bit of a black art. Mainly because mastering the regular expressions involved to accomplish tasks takes a bit of practice and some hits and misses before you get the desired results.

Fig: The online .htaccess editor

Now here is a very nice find. An online .htaccess editor which will hand hold you in creating your own custom made .htaccess file. All you have to do is click on your desired options such as whether to allow or deny access to all files, basic authentication, the redirect directives and so on.

Set up an Apache web server cluster in 5 easy steps

A server cluster is a group of independent servers that are managed as a single system for higher availability, easier manageability, and greater scalability.

In a Web server environment, server clusters can be defined in two basic ways:

Active/Active

• There are multiple independent, redundant servers
• The load is distributed through round-robin DNS
• The load is balanced by a load-balancing solution
  

Active/Passive

• Multiple servers are configured to provide a service
• Only a single server provides the service at any given time
• Other servers serve as hot-spares in case of a server (service) problem or a site hosted on the servers suddenly start getting load spikes such as when being slashdotted.
  

Now a days, many shared web hosting providers are turning to a web server cluster solution over managing individual web servers on independent machines. Clustering is said to provide some respite to the performance issues.

Eli M. Dow and Frank LeFevre, both, Software Engineers at IBM have written this insightful albeit rather technical article which explains how to setup an Apache web server cluster in 5 easy steps.

From the article ...

Spreading a workload across multiple processors, coupled with various software recovery techniques, provides a highly available environment and enhances overall RAS (Reliability, Availability, and Serviceability) of the environment. Benefits include faster recovery from unplanned outages, as well as minimal effects of planned outages on the end user.

To get the most out of this article, you should be familiar with Linux and basic networking, and you should have Apache servers already configured. Our examples are based on standard SUSE Linux Enterprise Server 10 (SLES10) installations, but savvy users of other distributions should be able to adapt the methods shown here.

Learn how to set up an Apache web server cluster in 5 easy steps.

.htaccess Tips and Tricks

Apache is one of the most popular web server which is stable and which scales very well. This web server which has been released under a free licence has the honor of powering many of the very high traffic sites, not to speak of the 100s of 1000s of ordinary websites dotting the net landscape.

Usually, when you host a website on a shared server, you are not provided any rights or access to modify the main configuration file (http.conf or apache2.conf depending on the OS on which the webserver runs) of the apache webserver. So you are severely constrained about changing the parameters of the web server (called server directives) and have to rely exclusively on the systems administrator manning the remote server.

This is where the .htaccess file has its use. By creating this hidden file in the root folder (or any sub folder) of your website, it is possible to set/unset almost all the server directives that can be set in the apache main configuration file. And these changes will take effect only for the root folder in which you created the file and its sub folders. Thus .htaccess file plays an important role in providing fine-grained control to an individual managing a website without giving blanket control of the web server.

For example, you can effectively use .htaccess file to deny access to everyone for certain folders residing withing your website directory. Or you can password protect your directory and allow access only to authorised people. But one of the most powerful and popular trick is to rewrite a particular URL using regular expressions. This can be useful if for instance, you have relocated some of the web content to another location thus changing the path of the file. So instead of giving a visitor an error page, you can write a couple of lines in a .htaccess file which will redirect the user to the new location of the web page.

Today, I came across this two part series (Part I and Part II) titled '.htaccess tips and tricks' which explains many of the tasks one can achieve using the .htaccess file which makes an informative read.