Funny and malicious server banners

This article has been indexed from

Netcraft News

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”.

Screenshot of Chrome's Network Inspector

Chrome’s Network Inspector showing the HTTP response headers for wordpress.com, which uses the nginx web server. It does not reveal a version number.

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.

Custom banners

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 “Apache”.

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

[…]
Content was cut in order to protect the source.Please visit the source for the rest of the article.

Read the original article: