The Naptha vulnerabilities are a type of denial-of-service vulnerabilities researched and documented by Bob Keyes of BindView’s RAZOR Security Team in 2000. The vulnerabilities exist in some implementations of the TCP protocol, specifically in the way some TCP implementations keep track of the state of TCP connections, and allow an attacker to exhaust the resources of a system under attack without utilizing much resources on the system used to launch the attack.

The following links provide more information about the Naptha denial-of-service vulnerabilities:

• The original BindView advisory is archived here.
• The advisory that CERT/CC published for the Naptha vulnerabilities is here.

The Tool

To study and show the Naptha vulnerabilities, Bob Keyes wrote the Naptha tool. The tool was written in C and used libpcap to read packets from the network and libdnet to craft packets.

The Naptha tool actually consists of two programs: a program called synsend whose only function is to send TCP SYN packets to the target system, and a program called srvr whose function is to respond to specific traffic received from the target system with TCP packets with specific TCP flags set. Both what traffic to respond to and how to respond to it are specified by the user via command-line arguments.

You can download Naptha here:

naptha-1.1.tgz

Or read more here.