Credit: WordPress / Thinkstock WordPress sites with the plug-in Fancybox-for-WordPress should apply a critical security update released Thursday that fixes a vulnerability already exploited by attackers.Researchers from Web security firm Sucuri issued a warning about the vulnerability Wednesday after seeing attacks that injected a malicious iframe into websites.They tracked down the problem to a flaw in Fancybox-for-WordPress, which allows webmasters to easily integrate the Fancybox JavaScript library into their WordPress sites. FancyBox is a tool for displaying images, HTML content and multimedia in a so-called “lightbox” that floats on top of Web pages.Fancybox-for-WordPress has been downloaded almost 600,000 times from the official WordPress plug-in repository to date. “After some analysis, we can confirm that this plugin has a serious vulnerability that allows for malware (or any random script/content) to be added to the vulnerable site,” the Sucuri researchers said in a blog post in which they advised users to remove the plug-in because the flaw was unpatched.That might no longer be necessary as the plug-in’s developers released two new versions in rapid succession Thursday to fix the vulnerability. Version 3.0.3 addresses the actual flaw, while version 3.0.4 renames the plug-in setting where the issue originated. “This should stop the malicious code from appearing on sites where the plugin is updated without removing the malicious code,” the plug-in developers said in the changelog.Users are advised to update to the latest version — 3.0.4.WordPress sites are a favorite target for hackers, who compromise them to host malicious content and spam pages or to try and gain control of the underlying Web servers. Vulnerabilities in WordPress plug-ins and themes have been exploited before in large scale attacks that compromised thousands of websites. Related content feature Top cybersecurity M&A deals for 2023 Fears of recession, rising interest rates, mass tech layoffs, and conservative spending trends are likely to make dealmakers cautious, but an ever-increasing need to defend against bigger and faster attacks will likely keep M&A activity steady in By CSO Staff Sep 22, 2023 24 mins Mergers and Acquisitions Mergers and Acquisitions Mergers and Acquisitions brandpost Unmasking ransomware threat clusters: Why it matters to defenders Similar patterns of behavior among ransomware treat groups can help security teams better understand and prepare for attacks By Joan Goodchild Sep 21, 2023 3 mins Cybercrime news analysis China’s offensive cyber operations support “soft power” agenda in Africa Researchers track Chinese cyber espionage intrusions targeting African industrial sectors. By Michael Hill Sep 21, 2023 5 mins Advanced Persistent Threats Cyberattacks Critical Infrastructure brandpost Proactive OT security requires visibility + prevention You cannot protect your operation by simply watching and waiting. It is essential to have a defense-in-depth approach. By Austen Byers Sep 21, 2023 4 mins Security Podcasts Videos Resources Events SUBSCRIBE TO OUR NEWSLETTER From our editors straight to your inbox Get started by entering your email address below. Please enter a valid email address Subscribe