LogReceiver.exe in Rockwell Automation RSLinx Enterprise CPR9, CPR9-SR1, CPR9-SR2, CPR9-SR3, CPR9-SR4, CPR9-SR5, CPR9-SR5.1, and CPR9-SR6 allows remote attackers to cause a denial of service (service outage) via a zero-byte UDP packet that is not properly handled by Logger.dll.