Understanding PHP Backdoors in WordPress

What is a PHP Backdoor?

A PHP backdoor is a piece of malicious code written in PHP that allows an attacker to maintain persistent, covert access to a compromised WordPress site. Even if you update your plugins and change your passwords, the backdoor allows the hacker to get right back in.

How Attackers Hide Backdoors

Hackers are incredibly creative when it comes to hiding backdoors. They often disguise malicious files as legitimate core files (like wp-includes/class-wp-cache.php) or hide them within the code of inactive themes.

The Role of Obfuscation

To avoid detection by basic security scanners, attackers obfuscate their code. You might see functions like eval(base64_decode(...)). This takes a long string of unreadable characters, decodes it into a PHP script, and executes it on the fly. Nexura Security specializes in decoding and identifying these exact threats.