While we already are far ahead of other companies in keeping up with vulnerabilities in WordPress plugins (amazingly that isn’t an exaggeration), in looking in to how we could get even better we noticed that in a recent instance were a vulnerability was exploited in a plugin, we probably could have warned our customers about the vulnerability even sooner if we had looked at the plugin when it was first closed on the Plugin Directory instead of when the vulnerability was fixed (though as far as we are aware the exploitation started after we had warned our customers of the fix). So we are now monitoring to see if any of the 1,000 most popular plugins are closed on the Plugin Directory and then seeing if it looks like that was due to a vulnerability.
As part of making sure our customers are getting the best information on vulnerabilities in WordPress plugins they may be using we monitor for hackers probing for usage of plugins on our website and then try to figure out what the hackers might be looking to exploit. Today we have had what look to be hackers probing for usage of five plugins. Two of those have recently had vulnerabilities disclosed that involve persistent cross-site scripting (XSS). The other three do not appear to have had vulnerabilities recently disclosed, but have persistent XSS vulnerabilities as well. One of those plugins is FB Messenger Live Chat (Live Chat with Facebook Messenger), which has 30,000+ installs according to wordpress.org. In looking over the plugin we found that it contains a persistent cross-site scripting (XSS) vulnerability, which is a type of vulnerability hackers have been exploiting widely recently.