Advantech WebAccess File and Directory Information Exposure

The BWOCXRUN.BwocxrunCtrl.1 control contains a method named “OpenUrlToBuffer.” This method takes a URL as a parameter and returns its contents to the caller in JavaScript. The URLs are accessed in the security context of the current browser session. The control does not perform any URL validation and allows “file://” URLs that access the local disk. The method can be used to open a URL (including file URLs) and read file URLs through JavaScript. This method could also be used to reach any arbitrary URL to which the browser has access.