You can easily check WordPress for a virus several different ways both online and offline. WordPress sites are notorious for being susceptible to malware and other viruses. This is mainly due to third party themes that come bundled with plugins that are not always patched by the developer timely.
One of the easiest ways to identify if your WordPress site has been compromised by malware is to run an online scanner. Google’s VirusTotal is one of the best out there and analyzes millions of submissions each month. VirusTotal has a “URL” option and you can easily input your site’s web address and have it scanned. Once it completes scanning it will give you detailed results if it does find malware on your site.
The second option is an offline method to identify if a virus or malware is present on your site. For an offline search, you will need to download your entire site through FTP onto your local computer. For those that are wary about possibly downloading malware to your computer (especially if your running Windows) it is best to download your site as a compressed .zip. Then, you can utilize a virus scanner such as ClamAV to search the compressed archive contents.
Once you have determined if malware or a virus is present on your site you need to have it removed either by someone that offers this service, or you can do it yourself if you have knowledge of standard web programming languages. In order to remove the malware you will need to pay special attention to the scanner results and locations where the malware is present. You will then need to remove the malware from each individual file and also sanitize any other files that were compromised.
After you have removed all instances of malware or a virus on your site, you will need to run a scan on the site again to ensure it is now clean. Now that you have a clean site, the work is not over, you need to determine how your site was compromised and patch it accordingly so it does not happen again.