While WordPress is usually a secure and stable platform, it can fall victim to hackers when it is not maintained or when poorly developed or outdated plugins are used.
One of the most common methods for hackers to hide malicious PHP code inserted into WordPress is to base64-encode the hacked code and then use base64 decoding and eval() to execute the code at runtime. (If this has already exceeded your level of knowledge in PHP or WordPress, please consult a qualified website developer or WordPress expert for help.)
Fortunately for WordPress users, the base64 code is relatively easy to spot in PHP code and looks something like the following:
Since the base64 encoding appears as a long string of random alphanumeric characters, it stands out within the PHP code. Typically, a hacker uses this coding to embed PHP code within WordPress to generate links, redirect users to specific sites, and in the worst case, allow unauthorized access to the system and database. WordPress.
While it is possible to manually search for the base64 code in your WordPress theme code, there are some plugins available that help scan and detect potentially malicious code for you. One of the most popular plugins is BulletProof Security, which is designed to protect a WordPress website against XSS, RFI, CRLF, CSRF, Base64, Code Injection, and SQL Injection hacking attempts.
While using a plugin like this is more effective in protecting a WordPress site than relying on manual inspection, it is vitally important to review your WordPress theme and WordPress installation on a recurring basis. Understanding how your WordPress site is designed and configured will help you more easily identify situations where the site is not working normally. It will also make it easier for you to detect code structure changes that may indicate malicious code has been injected into your WordPress theme.
If you operate a WordPress site as part of a small business, or depend on site traffic as part of your ongoing web marketing campaign or membership campaign, consider hiring a professional web consultant with experience in WordPress security to review your WordPress installation. A malicious plugin can ruin the hard-earned reputation of a WordPress website and cause membership levels to plummet. An experienced WordPress security consultant can quickly and easily locate, remove, and repair damage caused by malicious PHP or JavaScript code, and help prevent such problems from reoccurring in the future.