Half a million widely trusted websites vulnerable to Heartbleed bug

A serious overrun vulnerability in the OpenSSL cryptographic library affects around 17% of SSL web servers which use certificates issued by trusted certificate authorities. Already commonly known as the Heartbleed bug, a missing bounds check in the handling of the TLS heartbeat extension can allow remote attackers to view up to 64 kilobytes of memory on an affected server. This could allow attackers to retrieve private keys and ultimately decrypt the server's encrypted traffic or even impersonate the server.

The Heartbleed bug write-up mentions Apache and nginx as being the most notable software using OpenSSL, and also points out that these have a combined active site market share of over 66% according to our April 2014 Web Server Survey. However, not all of these servers are running an HTTPS service, nor are they all running vulnerable versions of OpenSSL with heartbeats enabled.

Our most recent SSL Survey found that the heartbeat extension was enabled on 17.5% of SSL sites, accounting for around half a million certificates issued by trusted certificate authorities. These certificates are consequently vulnerable to being spoofed (through private key disclosure), allowing an attacker to impersonate the affected websites without raising any browser warnings.


Most vulnerable servers are using Apache.

Note that a small percentage of Microsoft web servers also appear to support the TLS heartbeat extension; these are actually likely to be vulnerable Linux machines acting as reverse proxy frontends to Windows servers.

Support for heartbeats was added to OpenSSL 1.0.1 (released in 2012) by Robin Seggelmann, who also coauthored the Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) Heartbeat Extension RFC. The new code was committed to OpenSSL's git repository just before midnight on new year's eve 2011.

OpenSSL's security advisory states that only versions 1.0.1 and 1.0.2-beta are affected, including 1.0.1f and 1.0.2-beta1. The vulnerability has been fixed in OpenSSL 1.0.1g, and users who are unable to upgrade immediately can disable heartbeat support by recompiling OpenSSL with the -DOPENSSL_NO_HEARTBEATS flag.

Popular sites which exhibit support for the TLS heartbeat extension include Twitter, GitHub, Yahoo, Tumblr, Steam, DropBox, HypoVereinsbank, PostFinance, Regents Bank, Commonwealth Bank of Australia, and the anonymous search engine DuckDuckGo.

Certificates and keys at risk of compromise should be revoked and replaced, particularly if they are used to protect sensitive data. Certificate Authorities, hosting companies and other interested parties can contact us for assistance in identifying affected certificates.

You can check whether your own HTTPS website might be vulnerable using the form below, and looking for the RFC6520 heartbeat TLS extension.

Netcraft site report
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Thousands of websites still hosted on Windows XP

Thousands of websites are still hosted on Windows XP computers, despite the operating system reaching the end of its extended support period today. After today, Microsoft will stop providing automatic security updates for Windows XP, and Microsoft Security Essentials will also no longer be available for Windows XP.

Originally released in 2001, Windows XP is currently used by more than 6,000 websites in Netcraft's April 2014 Web Server Survey. Although China is often regarded as one of the most prolific users of Windows XP, only 3% of these sites are hosted there, suggesting that Windows XP has a predominantly desktop role in China. The largest share (nearly a third) of all Windows XP-powered websites are actually hosted in the United States.

Distribution of Windows XP-powered websites (logarithmic scale)

Notably, there are 14 US government websites still running on Windows XP, including a webmail system used by the State of Utah. Unsupported web-facing Windows XP servers are likely to become prime targets for hackers, particularly if any new Windows XP vulnerabilities are discovered, as no security updates will be available to fix them.  To afford some breathing space, the UK Government recently struck a £5.5m deal for Microsoft to provide it with an extra year of support for Windows XP, although there are currently no Windows XP-powered websites under the gov.uk top-level domain.

One of the busiest sites still using Windows XP is TransFerry.com. This site was previously using Windows 2000, and perhaps more worrying is the significantly larger number of websites which still use Windows 2000. This version of Windows reached its extended support end date in July 2010, yet nearly half a million of today's websites are hosted on Windows 2000 servers, most of which are using the Microsoft IIS 5.0 web server software they were shipped with. This version of IIS is practically identical to that used by Windows XP (IIS 5.1).

Netcraft's April 2014 survey also found 50,000 websites which are hosted on even older Windows NT4 servers running Microsoft IIS 4.0, although three quarters of these sites are served from the same computer in Norway. One of the busiest sites still running on Windows NT4 is the Australian Postal Corporation's post.com.au, which has been using the same operating system for at least 13 years. Window NT4 and IIS 4.0 are also still used by Australia Post's Postbillpay bill payment service, airindia.co.in and by the French government's Ministère de l'Économie, des Finances et de l'Industrie.

.Aero Air Safety Site Hijacked

The website of the Agency for the Safety of Aerial Navigation in Africa and Madagascar (ASECNA) has been hijacked by hackers. Browsing to the site's homepage currently presents visitors with a PayPal phishing site, where visitors are asked to submit PayPal account details, including their password, address and credit card details. After entering these details, victims are redirected to the real PayPal website.


Visitors to the ASECNA homepage are automatically redirected to this phishy PHP script in the root directory.

ASECNA is responsible for managing 16 million square kilometers of airspace (1.5x the size of Europe), covering six flight information regions, but has yet to remove the phishing site from its own homepage. Netcraft detected and blocked the above PayPal phishing site on Tuesday, yet visitors to www.asecna.aero who ignore their browser's warnings are still being presented with the phishing content today (Friday). Comments within the source code suggest that the phishing site was designed by a man living in Salé, Morocco.

A second PayPal phishing site was also found in a subdirectory on the same server, but it has since been deleted. It is possible that it was deleted by the fraudster behind the current attack, as it would be peculiar for ASECNA to have deleted phishing content from a subdirectory while leaving the more obvious phishing content on its homepage. The deleted phishing site used a phishing kit which hid its author's hotmail.fr email address in a Base64 encoded string. This made it less obvious to anyone deploying the kit that a duplicate copy of any stolen credentials would also be surreptitiously emailed directly to the kit's author. The phishing kit author's email address links him to a Facebook account which places him in Rabat, a Moroccan city which attracts many commuters from Salé. The same email address has been found in several other phishing kits, including some which target Visa customers.

It is rather unusual to see phishing sites hosted on .aero domains because they can only be registered by eligible members of the aviation community. SITA (an air transport IT and communications specialist) is responsible for verifying eligibility, and may ask applicants to provide company documents and pilot licenses, which reduces the likelihood of a fraudster registering a .aero domain specifically for the purpose of phishing. Many other top-level domains are easier to register, and some are even free.

 .aero is a sponsored top-level domain (sTLD). The original agreement for the domain was signed in 2001, and domains became available for registration in March 2002. In 2009, SITA signed a new 10-year sponsorship agreement for the .aero sTLD with ICANN.


How the ASECNA site looked prior to the compromise.

Netcraft's April 2014 survey found more than 9,000 sites using the .aero sTLD, and in the past 6 months they have hosted a total of 9 phishing sites. Each attack used an established .aero website which was compromised to host phishing content, rather than using a .aero domain registered specifically for fraud.

It is not apparent how the ASECNA website was compromised, although it appears to be running Apache 2.2.14, which could be vulnerable to a plethora of security issues which can be exploited remotely. The server also uses PHP 5.2.5, which was released in 2007, and the entire 5.2 branch of releases reached end of life status at the beginning of 2011. Unless the server is using a backporting approach to software maintenance, this old version of PHP could also expose a large number of vulnerabilities to remote attackers.

Netcraft's continuously updated, professionally validated phishing feed is used throughout the internet infrastructure industry. In addition to internet registries, all of the main web browsers, along with major anti-virus companies, firewall vendors, SSL Certificate authorities, large hosting companies and domain registrars use Netcraft's feed to protect their user communities. Please contact us for more information about these services, or about Netcraft's phishing site takedown service.

Most Reliable Hosting Company Sites in March 2014

Rank Performance Graph OS Outage
hh:mm:ss
Failed
Req%
DNS Connect First
byte
Total
1 Datapipe FreeBSD 0:00:00 0.011 0.081 0.018 0.037 0.055
2 www.choopa.com Linux 0:00:00 0.011 0.163 0.074 0.157 0.204
3 ReliableServers.com Linux 0:00:00 0.015 0.177 0.075 0.154 0.199
4 Qube Managed Services Linux 0:00:00 0.019 0.095 0.036 0.076 0.076
5 Hyve Managed Hosting Linux 0:00:00 0.019 0.230 0.064 0.127 0.131
6 Anexia Linux 0:00:00 0.019 0.232 0.089 0.411 0.685
7 Bigstep Linux 0:00:00 0.022 0.244 0.065 0.177 0.209
8 Webzilla unknown 0:00:00 0.026 0.124 0.070 0.138 0.393
9 Netcetera Windows Server 2012 0:00:00 0.030 0.059 0.072 0.158 0.291
10 ServerStack Linux 0:00:00 0.030 0.081 0.075 0.148 0.148

See full table

Managed services provider Datapipe had the most reliable hosting company site in March, closely followed by Choopa in second place. Both of the top two hosting company sites experienced three failed requests, and therefore the tie for first place was broken by analysing average connection times. Datapipe had the lowest average connection time within the top ten of 18ms and therefore ranked in first place.

Datapipe has a 100% uptime record which now stretches back over eight years; its last outage occurred back in March 2006. Over this time Datapipe's infrastructure has proved it can withstand the brutal forces of nature, surviving several hurricanes, typhoons and a snow storm. Along with 100% uptime, Datapipe has a low proportion of failed requests which has led to them ranking in first place many times over the years.

Second-place Choopa is based in a data centre in Piscataway, New Jersey and additionally has infrastructure in Los Angeles, Amsterdam, and Tokyo. Choopa describes its infrastructure's architecture as redundant with no single point of failure, and has backed this up with a 100% Uptime SLA plus a 0% Packet Loss Guarantee within its network. Choopa offers IPv6 throughout its entire network using a dual stack approach — avoiding the need to tunnel over IPv4. Recently Choopa has launched its own SSD VPS service via a new brand Vultr.

In third place with four failed requests is ReliableServers which lists reliability as its number 1 policy. ReliableServers is based in New Jersey and purchases server racks and network bandwidth from Choopa in Piscataway which hooks its servers directly into Choopa's network. ReliableServers offers Dedicated hosting with a 100% uptime guarantee.

Elsewhere in the table Webzilla made its first appearance in the top ten, which may be a result of its recent infrastructure upgrades. Webzilla launched in 2005 and offers a range of hosting services including dedicated, cloud, colocation and CDN.

Linux powers almost all the hosting company sites in the top 10. The exceptions are FreeBSD running Datapipe's site in first place and Windows Server 2012 running Netcetera's site in ninth place.

Netcraft measures and makes available the response times of around forty leading hosting providers' sites. The performance measurements are made at fifteen minute intervals from separate points around the internet, and averages are calculated over the immediately preceding 24 hour period.

From a customer's point of view, the percentage of failed requests is more pertinent than outages on hosting companies' own sites, as this gives a pointer to reliability of routing, and this is why we choose to rank our table by fewest failed requests, rather than shortest periods of outage. In the event the number of failed requests are equal then sites are ranked by average connection times.

Information on the measurement process and current measurements is available.

April 2014 Web Server Survey

In the April 2014 survey we received responses from 958,919,789 sites — 39 million more than last month.

Microsoft made the largest gain this month, with nearly 31 million additional sites boosting its market share by 1.9 percentage points. IIS is now used by a third of the world's websites. Although this is not Microsoft's largest ever market share (it reached 37% in October 2007), this is the closest it has ever been to Apache's leading market share, leaving Apache only 4.7 points ahead. Although Apache gained 6.9 million sites, this was not enough to prevent its market share falling by 0.87 to 37.7%. nginx, which gained 3.1 million sites, also lost some of its market share.

More than 70% of this month's new IIS-powered websites are hosted in the US, followed by 22% in China. Nearly 20 million of the new IIS sites in the US are hosted by a single company, Nobis Technology Group, which was also responsible for much of Microsoft's growth in February. A smaller amount of Microsoft IIS growth was also seen on the Windows Azure platform (which will be renamed to Microsoft Azure on April 3), where the total number of active sites has grown by 25% since February, when we compared the platform against Amazon AWS. 84% of all active sites hosted on the Azure platform are running Microsoft web server software.

Many of the new IIS sites hosted by Nobis Technology Group feature similar content and form part of a Chinese link farm. Link farming is often an attempt to influence search engine results, and each individual site within a link farm is typically of little interest to a human. Netcraft's active sites metric therefore provides a better idea of how many websites are actively managed rather than being automatically generated en mass, such as link farm content and domain holding pages. Of the 114 million sites hosted by Nobis, only a fifth are counted as active sites.

In terms of active sites, Apache remains in a much stronger position with a 52% share of the market, compared with Microsoft's 11%. A significantly higher proportion of Apache sites are active: 26% of all Apache sites were deemed to be active, whereas only 6% of Microsoft's were. nginx takes a 14% share of the active sites market, putting it 3 points ahead of Microsoft.

Apache also fares well amongst the million busiest sites, where there is intrinsically very little interference from domain holding pages, link farms and other web spam. Here Apache takes a 53% share of the market, while nginx has 18% and Microsoft has 12%. Although only 3% of the top million sites use Google web server software, Google's dominance amongst the very busiest sites give it a presence on 8 of the top 10 sites.

Both Apache and nginx were affected by security vulnerabilities which were resolved during March, whereas Microsoft IIS has yet to be affected by publicly-known security issues this year.

The latest version of Apache (2.4.9) was released on March 17. The Apache Software Foundation describes this as representing fifteen years of innovation by the project, and this major release of the 2.4 stable branch is recommended over all previous releases. Nevertheless, it is still common for many websites to use the legacy 2.2 branch of releases, or even older versions. Apache 2.4.9 is primarily a security and bug fix release, although it also includes the changes introduced in 2.4.8, which was not actually released. A workaround for a bug in older versions of OpenSSL, which prevented the release of 2.4.8, has been included in 2.4.9.

Although Apache 2.4.8 was not released, the development version (Apache/2.4.8-dev) was found on 675 sites during this survey, which ran in March. Nearly all of these sites were running on FreeBSD servers which belonged to various Apache projects, mostly Apache HTTPD and Apache OpenOffice.

The stable branch of nginx was updated twice during March. Two bugs were resolved in nginx 1.4.6, which was released on March 4. nginx 1.4.7 was then released on March 18, addressing another bug and a heap buffer overflow vulnerability. This security vulnerability affected nginx's SPDY module, where a specially crafted request could allow a remote attacker to execute arbitrary code on a vulnerable web server. nginx is notable for its SPDY support, which is used extensively by CloudFlare and also by Automattic, which hosts millions of WordPress blogs and co-sponsored the development of the ngx_http_spdy_module. The same SPDY vulnerability also affected the mainline branch of nginx, which was resolved with the release of nginx 1.5.12.

Many of the new generic top level domains (gTLDs) are starting to appear in Netcraft's Web Server Survey in significant numbers. For example, the previous survey saw only one website using the .guru gTLD, whereas this month's survey (which ran during March) found 36 thousand. Other gTLDs which have shown significant growth since last month's survey include .photography, .today, .tips, .technology, .directory, .land, .gallery, .estate and .singles.

Amongst established TLDs, the number of sites using the .ga country code top level domain grew by 140% this month. The My GA website allows .ga domains to be registered for free from between 1 and 12 months, which has no doubt helped towards their goal of increasing the awareness of Gabon across the globe. The .ga ccTLD is administered by the Agence Nationale des Infrastructures Numériques et des Fréquences (ANINF) in Libreville, Gabon, while the registration process is provided by Freenom, who also provide free domain registrations for the more popular .tk ccTLD. Registered Freenom users are allowed an unlimited number of domain name renewals on both the .ga and .tk d domains, while paying customers can choose to register domains for as long as 10 years in one go and can automatically renew the registration.

Free and easily-registerable domain names are obviously attractive to fraudsters: During February, Netcraft blocked nearly 1,500 unique phishing sites hosted on .ga domains alone, and this figure jumped to more than 2,400 in March. The vast majority of these phishing attacks targeted Chinese companies, particularly the Taobao marketplace and the Alipay online payment escrow service.





DeveloperMarch 2014PercentApril 2014PercentChange
Apache354,956,66038.60%361,853,00337.74%-0.87
Microsoft286,014,56631.10%316,843,69533.04%1.94
nginx143,095,18115.56%146,204,06715.25%-0.31
Google20,960,4222.28%20,983,3102.19%-0.09
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WordPress hosting: Do not try this at home!

Compromised WordPress blogs were used to host nearly 12,000 phishing sites in February. This represents more than 7% of all phishing attacks blocked during that month, and 11% of the unique IP addresses that were involved in phishing.

WordPress blogs were also responsible for distributing a significant amount of web-hosted malware — more than 8% of the malware URLs blocked by Netcraft in February were on WordPress blogs, or 19% of all unique IP addresses hosting malware.

WordPress is the most common blogging platform and content management system in the world: Netcraft's latest survey found nearly 27 million websites running WordPress, spread across 1.4 million different IP addresses and 12 million distinct domain names. Many of these blogs are vulnerable to brute-force password guessing attacks by virtue of the predictable location of the administrative interface and the still widespread use of the default "admin" username.

But remarkably, not a single phishing site was hosted on Automattic's own WordPress.com service in February. WordPress.com hosts millions of blogs powered by the open source WordPress software. Customers can purchase custom domain names to use for their blogs, or choose to register free blogs with hostnames like username.wordpress.com.

Automattic's founder, Matt Mullenweg, was one of the original authors of WordPress when it was released in 2003. Automattic later handed the WordPress trademark to the WordPress Foundation in 2010, but still contributes to the development of WordPress. Such familiarity with the product likely explains why blogs hosted at Automattic are significantly more secure than average.

Bloggers can also go it alone — anybody can download the WordPress software from wordpress.org and deploy it on their own website, and some hosting companies also offer "one-click" installations to simplify the process. Bloggers who install WordPress on their own websites will often also be responsible for keeping the software secure and up-to-date. Unfortunately, in many cases, they do not.

Even well-known security experts can fall victim to security flaws in WordPress if it is not their core activity. For example, in 2007, the Computer Security Group at the University of Cambridge found their own Light Blue Touchpaper blog had been compromised through several WordPress vulnerabilities.

Versions of WordPress after 3.7 are now able to automatically update themselves, provided the WordPress files are writable by the web server process. This has its own security trade-off, however, as an attacker exploiting a new and unreported vulnerability (a zero-day) that has the ability to write files will have free rein over the whole WordPress installation — an attacker could even modify the behaviour of WordPress itself to disable any future automatic security updates.

Insecure plugins

Over its lifetime, WordPress has been plagued by security issues both in its core code and in the numerous third-party plugins and themes that are available. One of the most widespread vulnerabilities this decade was discovered in the TimThumb plugin, which was bundled with many WordPress themes and consequently present on a large number of WordPress blogs. A subtle validation flaw made it possible for remote attackers to make the plugin download remote files and store them on the website. This allowed attackers to install PHP scripts on vulnerable blogs, ultimately facilitating the installation of malware and phishing kits. Similar vulnerabilities are still being exploited today.

Many of the phishing sites blocked in February were still operational this month, including this Apple iTunes phishing site hosted on a marketing company's website.

Dropzones for WordPress phishing content

Note that the above phishing content is stored in the blog's wp-includes directory, which is where the bulk of the WordPress application logic resides. More than a fifth of all phishing content hosted on WordPress blogs can be found within this directory, while another fifth resides in the wp-admin directory. However, the most common location is the wp-content directory, which is used by just over half of the phishing sites.

The wp-content directory is where WordPress stores user-supplied content, so it is almost always writable by the web server process. This makes it an obvious dropzone for malware and phishing content if a hacker is able to find and exploit a suitable vulnerability in WordPress, or indeed in any other web application running on the server. Shared hosting environments are particularly vulnerable if the file system permissions allow malicious users to write files to another user's wp-content directory. Some examples of directory structures used by phishing sites hosted in this directory on WordPress blogs include:

/wp-content/securelogin/webapps/paypal/
/wp-content/plugins/wordpress-importer/languages/image/Google/Google/
/wp-content/uploads/.1/Paypal/us/webscr.htm

The wp-includes and wp-admin directories can also be written to by other users or processes if the WordPress installation has not been suitably hardened. Failing to harden a WordPress installation and keep all of its plugins up to date could result in a site being compromised and used to carry out phishing attacks. Enabling automatic background updates is an easy way to ensure that a WordPress blog is kept up-to-date, but a significant trade off is that every WordPress file must be writable by the web server user.

Some other examples of directory structures seen in phishing sites hosted on WordPress blogs include:

/wp-includes/alibaba_online/
/wp-includes/www.paypal.com.fr.cgi.bin.webscr.cmd.login.submit.login/
/wp-includes/js/online.lloydsbank.co.uk/

/wp-admin/js/www.credit-mutuel.fr/
/wp-admin/maint/RBS-Card/index.html
/wp-admin/Googledoc/

Interestingly, the wp-admin directory appears to be the favourite location for Apple phishing sites – these make up more than 60% of all phishing sites found in this directory.

Vulnerable WordPress blogs can also be used for other nefarious purposes. A botnet of more than 162,000 WordPress blogs (less than 1% of all WordPress blogs) was recently involved in a distributed denial of service (DDoS) attack against a single website. Attackers exploited the Pingback feature in these WordPress blogs (which is enabled by default) to flood the target site with junk HTTP requests, causing it to be shut down by its hosting company.

A quarter of the phishing sites hosted on WordPress blogs in February targeted PayPal users, followed by 17% which targeted Apple customers.

Please contact us (sales@netcraft.com) for pricing or further details about any of our anti-phishing and web application security testing services.