Sucuri 404javascript.js security issue or internal server error
<p>Just ran a scan and says that:  </p>

<blockquote>
  <p>/404javascript.js is the infected URL:
  Site error detected. <br> Details: php-error-headers-already-sent  </p>
</blockquote>

<p><strong>Warning:</strong>  </p>

<blockquote>
  <p>Cannot modify header information - headers already sent by (output started at /home/myfreeca/public_html/wp-  content/themes/valenti/header.php:86) in /home/myfreeca/public_html/wp-includes/pluggable.php on line <b>920</b><br /></p>
</blockquote>

<p><b>Its classed as 'Malware' via the Sucur test within iThemes, but as an 'Internal Server error' when checking the Sucur site. No 404javascript.js when I browse ftp either?</b></p>

<p>Line 920 of pluggable.php:  </p>

<pre><code>setcookie( AUTH_COOKIE,        ' ', time() - YEAR_IN_SECONDS, ADMIN_COOKIE_PATH,   COOKIE_DOMAIN );
</code></pre>

<p>Line 86 of header.php:  </p>

<pre><code>&lt;!--[if lt IE 7]&gt;&lt;html &lt;?php language_attributes(); ?&gt; class="no-js lt-ie9 lt-ie8 lt-ie7"&gt; &lt;![endif]--&gt;
</code></pre>

<p>Site functioning fine as I can tell, not sure if I have a security issue or just that I need to make a little change where required?</p>

<p>Anyone???</p>