Netcraft’s most recent Web Server Survey includes nearly 1.2 billion websites. Most of these sites return a server banner that shows which web server software they use, thus allowing us to determine the market shares of each server vendor since 1995.
Many of these server banners are simply short strings like “
Apache”, while others may include additional details that reveal which other software – and which versions – are installed on the server. One such example is “
Apache/2.2.32 (Unix) mod_ssl/2.2.32 OpenSSL/1.0.2k-fips DAV/2 PHP/5.5.38”.
A web server reveals its server banner via the Server HTTP response header. This string is not ordinarily exposed to users, but most browsers allow it to be viewed in the Network Inspector panel.
Web server software usually allows its server banner to be modified. A common reason for changing the default value is to reduce the amount of information that would be revealed to an attacker.
For example, if a web server advertises itself as running a vulnerable version of Apache, such as “
Apache/2.4.49” it could be more likely to come under attack than a server that reveals only “
Our Web Server Survey includes a few websites that return the following
Server header, which takes a deliberate swipe at the effectiveness of hiding this sort of information:
Server: REMOVED FOR PCI SCAN COMPLIANCE - SECURITY THROUGH OBSCURITY WORKS, RIGHT? - https://bit.ly/2nzfRrt
Of course, with this amount of flexibility, a cheeky or malicious administrator can configure a web server to pretend to be anything they want. Sometimes this is done in a deliberate attempt to cloak the truth or to mislead, while in others it may simply be done as a joke waiting to be found by anyone curious enough to look for the banner.
Unlikely server banners
Amongst the 1.2 billion websites, there are plenty of examples of unlikely server banners.
Netcraft has seen a large increase in survey scams impersonating well-known banks as a lure. These are often run under the guise of a prize in celebration of the bank’s anniversary, though in some cases a reward is promised just for participating.
These scams first came to Netcraft’s attention around 16 months ago, when businesses that were particularly useful during lockdown such as supermarkets, mobile phone networks, and delivery companies were targeted. The expansion of these attacks to use banks as a lure started in October 2021. To date we have seen over 75 distinct banks used as lures for these survey scams, with a global spread including banks from US, UK, Asia, and the Middle East.
Netcraft recently confirmed that a Bangladesh Army site was hosting an Outlook Web Access (OWA) web shell. Additionally, an OWA web shell was found on the Department of Arts and Culture site for the South-African Kwazulu-Natal province and an Iraqi government site was found to be hosting a PHP shell. Web shells are a common tool used by attackers to maintain control of a compromised web server, providing a web interface from which arbitrary commands can be executed on the server hosting the shell. OWA provides remote access to Microsoft Exchange mailboxes; since the disclosure of the ProxyLogon vulnerabilities in March, Microsoft Exchange has become a popular target for cyberattacks.
Netcraft has to date identified nearly 10,000 websites used in the distribution of the FluBot family of Android malware. As detailed in our previous articles on FluBot, these sites are unwittingly hosting a PHP script that acts as a proxy to a further backend server, allowing otherwise legitimate sites to deliver Android malware to victims. When visited by the intended victim, a “lure” is displayed that implores them to download and install the FluBot malware.
The most common lure themes are parcel delivery and voicemail messages, where the user is told to install the malicious app to track a parcel or listen to a voicemail message. One particularly interesting lure took advantage of FluBot’s infamy, by offering a fake “Android security update” that claimed to protect against the malware family. Users installing this “security update” would instead be infected with FluBot.
Most sites distributing FluBot malware also host legitimate content, suggesting they were compromised by the operators of this malware distribution network, without the knowledge of the site operator. While the use of unrelated domains makes the lures less convincing, as compared to domains specifically registered for fraud, it allows the malware distribution network to operate at a much larger scale.
These affected sites all have one factor in common: they run self-hosted WordPress instances. Netcraft believes the operators of this malware distribution network are actively exploiting well-known vulnerabilities in WordPress plugins and themes to upload malicious content onto insecure sites, joining a growing list of threat actors doing the same.
The Government of Eswatini’s website,
www.gov.sz, is running a
use website visitors' CPU power to mine cryptocurrency, most often without their knowledge or permission.
28th September and
The US and others may have withdrawn from Afghanistan, but many Afghan Government websites and email addresses under the .gov.af top-level domain are still very much dependent on services hosted outside of the country – mostly in the US.
By taking control of Afghanistan, the Taliban has inherited these government domains and now shares web hosting and mail servers with several other governments around the world, including the UK Government. In many cases, emails sent to .gov.af domains will be routed through US-hosted servers, presenting intelligence opportunities if the new Taliban government were to continue using them.