On October 30th, 2024, we received a submission for an Authorization Bypass via Reverse DNS Spoofing vulnerability in Anti-Spam by CleanTalk, a WordPress plugin with more than 200,000 active installations. This vulnerability makes it possible for an unauthenticated attacker to install and activate arbitrary plugins on a vulnerable site, which can be leveraged to achieve remote code execution. A few days later on November 4th, our Threat Intelligence Team discovered another vulnerability in the same functionality that could be leveraged to perform the same actions.
Props to mikemyers who discovered and responsibly reported this vulnerability through the Wordfence Bug Bounty Program. This researcher earned a bounty of $4,095.00 for this discovery.
Paid Wordfence users received a firewall rule to protect against any exploits targeting the first vulnerability, Authorization Bypass via Reverse DNS Spoofing, on October 30, 2024. Sites using the free version of Wordfence will receive the same protection 30 days later on November 29, 2024.
Paid Wordfence users received a firewall rule to protect against any exploits targeting the second vulnerability, Authorization Bypass due to Missing Empty Value Check, on November 4, 2024. Sites using the free version of Wordfence will receive the same protection 30 days later on December 4, 2024.
Wordfence contacted the CleanTalk team on October 30, 2024, and received a response on the same day. After providing full disclosure details, the developer released the first patch on November 1, 2024, and the second patch on November 14, 2024. We would like to commend the CleanTalk team for their prompt response and timely patch.
We urge users to update their sites with the latest patched version of Anti-Spam by CleanTalk, version 6.45 at the time of this writing, as soon as possible. All clients of ProtectYourWP.com were updated within 24 hrs of the patch releases.
Source and more details: https://www.wordfence.com/blog/2024/11/200000-wordpress-sites-affected-by-unauthenticated-critical-vulnerabilities-in-anti-spam-by-cleantalk-wordpress-plugin