CVE-2017-18543 in invite-anyone Plugin
Summary
by MITRE
The invite-anyone plugin before 1.3.16 for WordPress has incorrect access control for email-based invitations.
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Analysis
by VulDB Data Team • 11/26/2023
The CVE-2017-18543 vulnerability resides within the invite-anyone plugin for WordPress, a widely used tool designed to facilitate user invitation and registration processes. This plugin allows website administrators to send email invitations to users who can then register for accounts on the platform. The vulnerability specifically affects versions prior to 1.3.16, indicating that the issue was identified and patched in a subsequent release. The core problem stems from improper access control mechanisms that fail to adequately validate user permissions when processing email-based invitation requests.
The technical flaw manifests in the plugin's insufficient validation of user roles and capabilities during the invitation process. When users submit email addresses for invitations, the system should verify that the requesting user possesses appropriate administrative privileges to send such invitations. However, the vulnerability allows unauthorized users to bypass these access controls, enabling them to send invitations to any email address without proper authorization. This misconfiguration creates a pathway for privilege escalation and unauthorized account creation within the WordPress environment.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it can enable various malicious activities within the compromised WordPress installation. Attackers could exploit this weakness to flood the system with invitations to invalid email addresses, potentially leading to spamming campaigns or denial-of-service conditions. More critically, the vulnerability could facilitate account takeover attempts by allowing unauthorized users to invite themselves or others to create accounts with elevated privileges. This weakness directly violates the principle of least privilege and can undermine the overall security posture of WordPress sites using the affected plugin.
The vulnerability aligns with CWE-285, which addresses improper authorization issues in software systems, and represents a classic case of insufficient access control validation. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and initial access through application vulnerabilities. The weakness creates opportunities for adversaries to establish persistent access points within WordPress environments, potentially leading to further exploitation of the underlying system. Organizations using vulnerable versions of the invite-anyone plugin face significant risk of unauthorized user registration and potential compromise of their user management systems.
Mitigation strategies should prioritize immediate patching to version 1.3.16 or later, which contains the necessary access control improvements. Administrators should also implement additional monitoring of invitation activities and user registration patterns to detect anomalous behavior. Network-level controls such as rate limiting for invitation requests can provide additional defense-in-depth measures. Regular security audits of installed WordPress plugins should be conducted to identify and remediate similar vulnerabilities. The incident underscores the critical importance of maintaining up-to-date software components and implementing robust access control mechanisms within content management systems to prevent unauthorized user provisioning and privilege escalation.