WordPress has disclosed a critical privilege escalation vulnerability patched on January 26 with the release of version 4.7.2. The developers of the content management system (CMS) said they wanted to make sure users were protected against potential attacks before making the details public.
When it announced the release of version 4.7.2, WordPress said the latest version patched three vulnerabilities, including SQL injection, cross-site scripting (XSS) and access control issues.
However, it turns out that WordPress 4.7.2 also addresses a severe privilege escalation flaw that can be exploited to hijack websites. Fortunately, there is no evidence that the weakness has been exploited in the wild.
The security hole, discovered by researchers at Sucuri, has been described by WordPress developers as an unauthenticated privilege escalation vulnerability in a REST API endpoint. The flaw affects WordPress websites running versions 4.7.0 and 4.7.1.
By sending a specially crafted request, an unauthenticated attacker can change the content of any post on the targeted website. Next, they can add plugin-specific shortcodes and exploit other flaws that would normally be restricted to users with elevated privileges. An attacker can also abuse the compromised website for SEO spam, to inject ads, and even execute PHP code, depending on which plugins are enabled.
In a blog post published on Wednesday, WordPress Core Contributor Aaron D. Campbell explained that the disclosure of the vulnerability was delayed by one week to give websites time to update their installations.
Sucuri’s Marc-Alexandre Montpas reported the vulnerability to WordPress on January 20 and a fix was created shortly after. While the patch was being tested by developers, Sucuri configured its Web Application Firewall (WAF) to block exploitation attempts and WordPress reached out to companies such as SiteLock, Incapsula and CloudFlare so that they could protect their customers as well. WordPress hosts were also notified and provided instructions on how to protect users.
“Data from all four WAFs and WordPress hosts showed no indication that the vulnerability had been exploited in the wild,” Campbell said. “As a result, we made the decision to delay disclosure of this particular issue to give time for automatic updates to run and ensure as many users as possible were protected before the issue was made public.”