Security researchers have discovered two critical vulnerabilities in the Simple Membership plugin for WordPress, affecting versions 4.3.4 and earlier, posing potential privilege escalation threats.
Furthermore, this plugin, widely used for custom membership management on WordPress sites, had over 50,000 active installations. The vulnerabilities, reported by Patchstack, include an Unauthenticated Membership Role Privilege Escalation flaw and an Authenticated Account Takeover vulnerability.
The former allowed unauthenticated users to register accounts with arbitrary membership levels, while the latter permitted authenticated users to take over member accounts through an insecure password reset process.
In the case of the Unauthenticated Membership Role Privilege Escalation vulnerability, the flaw stemmed from a function handling the registration process, particularly the password reset via a reset password link feature. Attackers could manipulate the function using specific GET parameters to register with any membership level from an arbitrary member account.
On the other hand, the Authenticated Account Takeover vulnerability involved a separate function that handled password reset via a link feature. With careful manipulation of parameters, attackers could seize control of a user’s account.
The plugin developer, smp7 and wp.insider, acted swiftly upon receiving the report from Patchstack, addressing these vulnerabilities. They released version 4.3.5 on August 30, 2023, implementing checks to validate user-controlled parameters in custom registration and password reset processes.
This update aimed to secure the thousands of active installations using the Simple Membership plugin and mitigate the risks associated with the identified vulnerabilities.