Computer Associates ARCserve for NT 6.61 SP2a and ARCserve 2000 7.0 creates a hidden share named ARCSERVE$, which allows remote attackers to obtain sensitive information and overwrite critical files.
https://exchange.xforce.ibmcloud.com/vulnerabilities/7122
http://www.securityfocus.com/bid/3342
http://support.ca.com/Download/patches/asitnt/QO00945.html
http://archives.neohapsis.com/archives/bugtraq/2001-09/0137.html