RBX

This might also be because of some conflict with iThemes security plugin. I’ll report here after investigating it.

I just checked HTML and there are quite some errors in menu code. I guess the Envato’s quality check is done just on initial version and not on subsequent updates.

Can one vulnerable site on server cause other sites to be hacked?

We have several sites on same server, and these days I ensure proper security on new sites right from start to avoid possibility of malware creeping into backups.

My sites are still getting hacked, and all of them get hacked around the same time. I have enabled file change detection on several of them, and no changes seem to be made to files. Just all usernames are renamed to admin and passwords probably to admin123.

What do you think about exec() ability? I once enabled it to use EWWW image optimizer. Does it, or any other similar feature pose a risk?

I’m sorry for any misunderstanding. I’m a bootstrap noob, and certainly don’t know what I’m talking about. What I tried was code made available on wp-bootstrap-navwalker page, and had to make a few modifications to get it to work, but wasn’t able to set collapse setting to be different on desktop and mobile view.
After analyzing the Virtue code, it appears that two different menus are required for mobile and desktop (and hence a mobile navigation menu location is provided in options).

The website isn’t online yet, but I was able to copy code from Virtue menus to make this, which works, but I’m not sure it would if I replace the IDs to be unique.

function create_sidebar_menu($name) {
	?>
	<nav id="nav-main" class="hidden-sm hidden-xs hidden-ss">
		<h3><?php _e($name) ?></h3>
		<?php
		wp_nav_menu([
			'theme_location' => 'bwit_lsb_nav',
			'menu_class'     => 'sf-menu sf-js-enabled',
		]);
		?>
	</nav>
	<nav class="navbar navbar-right" role="navigation">
		<div id="mobile-nav-trigger" class="nav-trigger">
			<button class="nav-trigger-case mobileclass collapsed" data-toggle="collapse"
			        data-target=".kad-nav-side-collapse">
				<span class="kad-navbtn"><i class="icon-reorder"></i></span>
				<span class="kad-menu-name"><?php _e($name) ?></span>
			</button>
		</div>

		<div id="kad-mobile-nav" class="kad-mobile-nav">
			<div class="kad-nav-inner mobileclass">
				<div style="height: 0px;" class="kad-nav-side-collapse collapse">
					<?php
					wp_nav_menu([
							'theme_location' => 'bwit_lsb_nav',
							'depth'          => 0,
							'container'      => false,
							'menu_class'     => 'kad-mnav',
							'fallback_cb'    => 'wp_page_menu',
							'walker'         => new wp_bootstrap_navwalker()]
					);
					?>
				</div>
			</div>
		</div>
	</nav>
	<?php
}