Host Header Injection Fix vs Simple SMTP

👉 Enables custom headers for WP email notifications 👉 Also provides a “set it and forget it” security fix for WP < 5.5 👉 Uses only 50KB of code, so super lightweight, fast, and effective Important As of WordPress 5.5, this plugin no longer is necessary to fix the host-header security issue reported in Ticket #25239 finally is fixed, and mentioned in this post WordPress 5.5 Beta 4. Thank You WordPress devs! Is this plugin still useful? Yes, it enables you to choose the “From”, “Name”, and “Return-Path” headers for all WP notification emails. And for versions of WordPress less than 5.5, this plugin continues to fix the host-header injection security issue. Features This simple plugin does three things: Sets custom From, Name, and Return-Path for WP notifications Fixes a security vulnerability in WordPress versions < 5.5 Fixes a bug where invalid email addresses may be generated (in WordPress versions < 5.5) Choose from the following options: Use WordPress defaults (insecure for WP < 5.5) Use “Email Address” from WP General Settings Use a custom name and address Plus there is an option to use the specified From address as the Return-Path header. Why? The security issue fixed by this plugin has been known about since way back in WordPress version 2.3. There has been some talk about fixing, but nothing has been implemented. While the issue does not affect all sites, it does affect a good percentage of them, including some of my own projects. So, not wanting to get hacked, I decided to write my own solution. Hopefully this issue gets fixed in a future version of WordPress, and this plugin will become unnecessary. As a bonus, setting an explicit From address resolves a long-standing bug whereby an invalid email address is generated under the following conditions: A “From” address is not set, And the $_SERVER['SERVER_NAME'] is empty So by explicitly setting a “From” address, we prevent this bug from happening. Security Issue What is the security issue addressed by this plugin? Follows is a quick summary. To learn more in-depth, check out the resources linked in the next section. WP uses $_SERVER['SERVER_NAME'] to set the “From” header in email notifications This includes sensitive email notifications like password resets and user registration In some cases, an attacker could modify the “From” header and intercept the email Using the intercepted email, an attacker could gain access to your site and wreak havoc More Infos This security vulnerability is well-known and has been around for a looong time. To learn more, check out these articles: WP Core Trac Ticket Exploit Box Info Exploit Database Privacy This plugin does not collect or store any user data. It does not set any cookies, and it does not connect to any third-party locations. Thus, this plugin does not affect user privacy in any way. Host Header Injection Fix is developed and maintained by Jeff Starr, 15-year WordPress developer and book author. Support development I develop and maintain this free plugin with love for the WordPress community. To show support, you can make a donation or purchase one of my books: The Tao of WordPress Digging into WordPress .htaccess made easy WordPress Themes In Depth Wizard’s SQL Recipes for WordPress And/or purchase one of my premium WordPress plugins: BBQ Pro – Blazing fast WordPress firewall Blackhole Pro – Automatically block bad bots Banhammer Pro – Monitor traffic and ban the bad guys GA Google Analytics Pro – Connect WordPress to Google Analytics Head Meta Pro – Ultimate Meta Tags for WordPress REST Pro Tools – Awesome tools for managing the WP REST API Simple Ajax Chat Pro – Unlimited chat rooms USP Pro – Unlimited front-end forms Links, tweets and likes also appreciated. Thank you! 🙂

Adds a simple, no-fuss SMTP settings to your WordPress installation that lets you define custom settings, which is especially useful for hosts with no control over the php mail functionality. If logging is enabled, a new segment in the settings panel will show up with a 30-day overview of recent emails, and will automatically prune older logs. Please see the FAQ if you want a more permanent solution. For more information, please see the project wiki on GitHub. Environment and constant overriding (optional) This plugin will prefer environmental and constant-stored values over the plugin-saved equivalent settings, making it easier to use this plugin via deployment. These can be either stored in your systems env setup, or in wp-config.php as define( 'SEE_BELOW', 'your_value_here' );. Accepted Parameters SMTP_HOST (string) Mail server hostname. SMTP_PORT (integer) Port address (usually 25, 465 or 587). SMTP_AUTH (integer, 1 or 0) Pass below credentials to your mail server. SMTP_USER (string) The mail username for this account. SMTP_PASS (string) The password for the mailer account. SMTP_FROM (string) Enforce all emails come from this email address. SMTP_FROMNAME (string) Enforce all emails to have a certain email name. SMTP_SEC (string) Use a particular email security method (accepts ‘def’ (default), ‘ssl’, ‘tls’ and ‘off’). SMTP_NOVERIFYSSL (boolean) Disable validation of the SMTP server certificate (not recommended). SMTP_LOG (boolean) Controls the logging capability and visibility. SMTP_DISABLE (boolean) Disables the mailer. They will still be logged if enabled, but won’t send out. It is recommended to store at least SMTP_PASS in your wp-config.php file (with the correct file permissions set). If the openssl extension is available, the plugin will attempt to encrypt the password in the database.