The popular WordPress plugin Gravity Forms suffered from a supply chain attack. As a result, installers from the official website were infected with a backdoor.
Gravity Forms is a premium plugin for creating contact, payment, and other online forms. According to official statistics, it is installed on approximately one million sites, some of which belong to well-known organizations such as Airbnb, Nike, ESPN, Unicef, and Google.
Experts from PatchStack warn that they have received reports of suspicious requests being generated by plugins downloaded from the official Gravity Forms website.
Upon examining the plugin, researchers confirmed that a malicious file (gravityforms/common.php) is indeed being downloaded from the manufacturer’s website. Closer inspection revealed that this file initiates a POST request to a suspicious domain at gravityapi[.]org/sites.
Further analysis revealed that the plugin collects a wealth of metadata from sites, including the URL, path to the admin panel, as well as data about themes, plugins, and PHP/WordPress versions. All the collected data is transmitted to the attackers.
The server’s response from the hackers contains malicious PHP code encoded in base64, which is saved as wp-includes/bookmark-canonical.php. This malware disguises itself as WordPress Content Management Tools and allows remote code execution without the need for authentication by utilizing functions such as handle_posts(), handle_media(), handle_widgets().
RocketGenius, the company developing Gravity Forms, was notified of the issue, after which a representative informed researchers that the malware had infiltrated only the plugin versions installed manually and through Composer.
Experts recommend that anyone who downloaded Gravity Forms on July 10-11, 2025, reinstall the plugin by obtaining a clean version. Additionally, administrators need to check their sites for signs of infection.
The representatives from RocketGenius have already published an incident analysis, confirming that only versions 2.9.11.1 and 2.9.12 of Gravity Forms, available for manual download from July 10 to July 11, 2025, were compromised. It is also noted that if users installed version 2.9.11 via Composer on any of the mentioned dates, they also received an infected copy of the plugin.
“The Gravity API service, which handles licensing, automatic updates, and the installation of add-ons initiated by Gravity Forms, has not been compromised. The attack did not affect the package updates managed by this service,” the developers stated.
According to the developer, the malicious code blocked update attempts, connected to an external server to receive additional payloads, and added an administrator account to the site, giving attackers full control over the compromised resource.