We just had one of our main web application servers fall victim to a denial of service attack yesterday.  It turns out that the APC PowerChute Business edition software (for the UPS system) has a major flaw that allows someone to issue a denial of service attack on systems running affected versions of the software (6.0-7.0.1).

The symptoms:

• Symantec AntiVirus was disabled and would not start up
• Internet Explorer started normally, but would only display a blank white screen
• Services could not be manually stopped or started
• Control panel was unresponsive
• ArcIMS failed to start after a reboot
• The powerchute services (server and agent) were stuck on "starting" and they could not be disabled from starting up

To fix it we manually removed the services from the registry and then uninstalled the software.

http://www.securitytracker.com/alerts/2004/Jul/1010745.html

Cheers,

Jeremy