On March 10, 2022 the Wordfence Threat Intelligence team initiated the responsible disclosure process for a vulnerability they discovered in “SiteGround Security”, a WordPress plugin that is installed on over 400,000 sites. This flaw makes it possible for attackers to gain administrative user access on vulnerable sites when two-factor authentication (2FA) is enabled but not yet configured for an administrator.
A patch was released the next day on March 11, 2022. While the plugin was partially patched immediately, it wasn’t optimally patched until April 7, 2022.
SiteGround Security is a plugin designed to enhance the security of WordPress installations via several features like login security including 2FA, general WordPress hardening, activity monitoring, and more. It’s also worth noting that it comes pre-installed on all SiteGround hosted WordPress sites. Unfortunately, the 2FA functionality of the plugin was insecurely implemented making it possible for unauthenticated attackers to gain access to privileged accounts.
Source & more details: https://www.wordfence.com/blog/2022/04/critical-authentication-bypass-vulnerability-patched-in-siteground-security-plugin