Hackers are actively exploiting a vulnerability in outdated versions of the Popup Builder plugin for WordPress, infecting over 3,300 websites with malicious code. Tracked as CVE-2023-6000, this cross-site scripting (XSS) vulnerability affects Popup Builder versions 4.2.3 and older, initially disclosed in November 2023. Despite earlier warnings and campaigns, Sucuri has observed a recent surge in attacks targeting the same vulnerability, demonstrating the continued risk posed to WordPress sites.
The injected code manipulates Popup Builder plugin events to execute malicious actions, primarily redirecting visitors to phishing pages and malware-infected sites. This underscores the urgency for site administrators to update to the latest plugin version, 4.2.7, to mitigate these risks effectively. However, WordPress statistics reveal that a significant number of active sites—over 80,000—are still using older versions of Popup Builder, leaving them vulnerable to exploitation.
Sucuri advises blocking domains associated with the attacks and recommends thorough scanning for hidden backdoors in infected sites to prevent reinfection. Removal of malicious entries from Popup Builder’s custom sections is essential to cleanse infected sites. The ongoing exploitation of this vulnerability emphasizes the importance of proactive security measures, including prompt software updates and vigilant monitoring, to safeguard WordPress sites against emerging threats.
