What are the main security concerns with PHP development in WordPress plugins?

1 SQL Injection

SQL injection is a type of attack that exploits a vulnerability in the database query code, allowing an attacker to execute malicious SQL commands and access or manipulate data. SQL injection can result in data theft, corruption, or deletion, as well as unauthorized access to other systems. To prevent SQL injection, developers should use prepared statements or parameterized queries, which separate the SQL code from the user input and prevent the injection of arbitrary commands. Developers should also validate and sanitize user input, and use the least privileged database user account.

3 File Inclusion

File inclusion is a type of attack that allows an attacker to include a file from a remote or local source into the PHP code, and execute it on the server. File inclusion can result in code execution, information disclosure, or file manipulation. To prevent file inclusion, developers should avoid using dynamic file names or user input in the include or require functions, and use absolute paths instead of relative paths. Developers should also disable the allow_url_include and allow_url_fopen directives in the php.ini file, which prevent the inclusion of files from external sources.

4 Code Injection

Code injection is a type of attack that allows an attacker to inject and execute arbitrary PHP code on the server, bypassing any security mechanisms or filters. Code injection can result in complete compromise of the server, as well as remote code execution on other systems. To prevent code injection, developers should never use the eval, assert, or create_function functions, which execute any string as PHP code. Developers should also avoid using variable variables or variable functions, which can be manipulated by user input. Developers should also use output buffering and obfuscate the plugin code to make it harder for attackers to find vulnerabilities.

5 File Upload

File upload is a feature that allows users to upload files to the server, which can be useful for various purposes, such as media, documents, or backups. However, file upload also poses a security risk, as an attacker can upload malicious files that can execute on the server or infect other files. To prevent file upload attacks, developers should limit the file size, type, and extension, and use a whitelist approach instead of a blacklist approach. Developers should also rename the uploaded files and store them in a separate directory, and use the is_uploaded_file and move_uploaded_file functions to verify and handle the files. Developers should also scan the uploaded files for viruses or malware, and use the .htaccess file to prevent direct access to the files.

6 Directory Traversal

Directory traversal is a type of attack that exploits a vulnerability in the file system access code, allowing an attacker to access or manipulate files or directories that are outside the intended scope. Directory traversal can result in information disclosure, file deletion, or code execution. To prevent directory traversal, developers should validate and sanitize user input, and use the basename and realpath functions to remove any dot-dot-slash sequences or symbolic links. Developers should also use the open_basedir directive in the php.ini file, which limits the directories that can be accessed by PHP scripts. Developers should also use the .htaccess file to restrict access to sensitive files or directories.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?