Block old browser versions and suspicious browsers

There are many ways to block unwanted access to your website. This plugin checks which user agent is accessing your website. If it is outdated, unwanted, or suspicious, access is blocked.

Every time a web browser sends a request to a website, then it sends a HTTP Header called the “User Agent”. The User Agent string contains information about the web browser name, operating system, device type and lots of other useful bits of information.

The plugin sends with an API the User Agent string of every browser that accesses your website for the first time to https://api.whatismybrowser.com/api/v3/detect to obtain following information about the User Agent:

• Software Name & Version
• Operating System Name & Version

With this information, the plugin attempts to detect old and bad browsers and denies them access to your website.

HowTo

• Go to What is my browser? and sign up to the WhatIsMyBrowser.com API for a Basic (free) Application Plan.
• Take care about the WhatIsMyBrowser.com API Terms and Conditions.
• You have a limit of 5000 hits / month for Parsing User Agent. That’s why the plugin manages a database table.
• The user agent string of every browser that accesses your website for the first time is sent to this service, and the information is stored this table.

Privacy

If you have concerns about data privacy: The user agent string is sent to this service only once and never again after that (unless the database entries are deleted). According to my hosting provider, over the past 12 months, I’ve had over 140000 visitors to my websites, but there are “only” < 7,000 entries in the database. And most of them (in my case, over 80%) come from outdated browsers or are suspicious. Just “140000” – that’s because my websites are only of interest to a select group of users. Other websites have significantly more visitors. However, I don’t think the number of user-agent strings will be significantly higher.

Functions

• The plugin checks whether the browser is up to date; it does not check whether the requested page or post actually exists.
• Browsers are blocked if the browser and/or system are outdated:
  • Default: Chrome, Edge and Chrome based browsers < 147, Firefox browsers < 140, Safari < 18, Samsung Browser < 30, Internet Explorer, Netscape (!)
  • Old systems are all Windows versions prior to Windows 10, MacOS prior to Catalina and Android versions < 10 and Symbian.
• It will be blocked also if “Software” contains “unknown” or is empty.
• You can also set up other browsers.
• Sometimes there are false positive, for example, if the browser is from Mastodon. In this case, you can exclude it from the check.
• The plugin checks whether the crawlers really originate from Google, Bing, Yandex, Apple, Mojeek, Baidu, Seznam and others.
• The plugin blocks browsers like Chrome, Firefox and other without Sec-Fetch headers (Sec-Fetch-Site, Sec-Fetch-Mode, Sec-Fetch-Dest) and incorrect Client hints (Sec-CH-UA, Sec-CH-UA-Platform).

About robots.txt

• You can configure some rewrite rules to provide a robots.txt file that can allow or deny crawling for a browser. If crawling is denied, access to your website will be blocked for that browser.

Logging

• The logging can be very detailed. Please check the logs and the WIMB table regularly.