The Ultimate Member – User Profile, Registration, Login, Member Directory, Content Restriction & Membership Plugin plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 2.11.0 via the ajax_get_members function. This is due to the use of a predictable low-entropy token (5 hex characters derived from md5 of post ID) to identify member directories and insufficient authorization checks on the unauthenticated AJAX endpoint. This makes it possible for unauthenticated attackers to extract sensitive data including usernames, display names, user roles (including administrator accounts), profile URLs, and user IDs by enumerating predictable directory_id values or brute-forcing the small 16^5 token space.
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
There are many different kinds of mistakes that introduce information exposures. The severity of the error can range widely, depending on the context in which the product operates, the type of sensitive information that is revealed, and the benefits it may provide to an attacker. Some kinds of sensitive information include:
Information might be sensitive to different parties, each of which may have their own expectations for whether the information should be protected. These parties include:
Information exposures can occur in different ways:
It is common practice to describe any loss of confidentiality as an “information exposure,” but this can lead to overuse of CWE-200 in CWE mapping. From the CWE perspective, loss of confidentiality is a technical impact that can arise from dozens of different weaknesses, such as insecure file permissions or out-of-bounds read. CWE-200 and its lower-level descendants are intended to cover the mistakes that occur in behaviors that explicitly manage, store, transfer, or cleanse sensitive information.