In the August 2016 survey we received responses from 1,153,659,413 sites and 5,980,524 web-facing computers. This reflects an increase of 80 million sites, but a loss of 78,000 computers.

While the overall number of sites increased this month, this growth was not felt evenly by each web server vendor: Microsoft gained the largest number of sites with an increase of 66 million, while second-placed Apache lost 41 million sites. Tengine, the nginx-based web server from Chinese online shopping giant Taobao, gained 28 million sites.

Whilst there were large changes in total number of sites, these were accompanied by much more modest changes in active sites – a more stable metric designed to ignore automatically generated bulk content. Apache and Microsoft both suffered small drops in the number of active sites, -0.5% and -0.8% respectively, whilst Tengine and nginx gained 120,000 (7.3%) and 81,000 (0.2%).

The majority of this month’s drop in web facing computers were running Apache, with a decrease of just over 107,000 (3.8%) using the open-source server. One of the primary contributors to this drop was the loss of a large number of consumer-NAS devices running Apache. While these devices have steadily increased in number since the start of 2016, this month has seen a marked decline. These devices are mostly connected via home internet lines and are therefore likely to come and go from month to month. As a result, the Apache losses this month are spread over a large number of consumer ISPs. On the other hand, Apache continued to see growth amongst web hosting providers.

A gain of 24,000 web-facing computers for nginx, the largest gain in web facing computers this month, once more boosts its market share, which now stands at 17.0%. Microsoft also experienced a small increase in market share, despite its loss of 4,000 web-facing computers, given Apache’s large loss this month.

Windows Server 2016 — which will be the main platform for Microsoft IIS 10.0 — is edging closer to its official launch at Microsoft's Ignite conference in September. In the meantime, developers can try out many of the new features in IIS 10 by either installing the latest Windows Server 2016 Technical Preview 5, or by installing the self-contained IIS 10.0 Express on Windows 7 SP1 or later.

More than 11,000 websites are already using Microsoft IIS 10.0, with almost all of these sites using a version of Windows Server 2016.

The previous month saw two new releases of the mainline version of nginx, mostly incorporating bug fixes and feature additions, while the release of Apache 2.4.23 addressed a security issue which could have allowed clients to gain unauthorised access to protected resources if a server was configured to use HTTP/2.

Several web servers were also updated following the disclosure of a set of vulnerabilities dubbed httpoxy. These vulnerabilities can affect web applications running in CGI or CGI-compatible environments.

The vulnerability stems from a simple namespace conflict where the client-provided HTTP Proxy header was placed into an HTTP_PROXY environment variable as is the custom for CGI applications; but where HTTP_PROXY was trusted by the application and used to configure an outgoing proxy.

This type of vulnerability was first discovered in libwww-perl more than 15 years ago, but in July it was found to be still exploitable in PHP and many other modern languages and libraries. Successful exploitation of these issues could allow a remote attacker to proxy outgoing HTTP requests made by a vulnerable web application, which may expose sensitive data.

To mitigate the httpoxy vulnerability, Apache 2.4.24-dev avoids populating the HTTP_PROXY variable from a Proxy header in httpd CGI environments. Similar mitigations have also been implemented in Lighttpd 1.4.41 and LiteSpeed, while nginx and Varnish have published mitigation advice.

For more information see Active Sites