Oracle9iAS Web Cache 2.0.0.x allows remote attackers to cause a denial of service via (1) a request to TCP ports 1100, 4000, 4001, and 4002 with a large number of null characters, and (2) a request to TCP port 4000 with a large number of "." characters.
https://exchange.xforce.ibmcloud.com/vulnerabilities/7765
http://www.securityfocus.com/bid/3762