The plugin is hard coded to copy the styles.css file from $JENKINS_HOME/plugins/aqua-security-scanner/css/styles.css to the workspace directory (See github). However, if the Jenkins setting hudson.PluginManager.workDir has been changed to a non-default value then plugins are unpacked at that location instead of $JENKINS_HOME/plugins which causes the following exception:

Exception:java.io.IOException: Failed to copy [$JENKINS_HOME]/plugins/aqua-security-scanner/css/styles.css to [$WORKSPACE]/styles.css

How to reproduce

• Stop jenkins
• Remove all plugin folders from $JENKINS_HOME/plugins. Leave the jpi files.
• Start jenkins with hudson.PluginManager.workDir set to a directory other than $JENKINS_HOME/plugins
  • Plugin directories will be created in the new directory rather than $JENKINS_HOME/plugins
• Attempt to run a build using the Aqua plugin
  • The exception is thrown after the plugin has scanned the image