Denial of service warning for network security tool

Give it some stick

By John Leyden, 16th March 2001

Regcast training : Hyper-V 3.0, VM high availability and disaster recovery

A security firm has issued an alert about a cracker tool which can be used to mount a denial of service attack (DoS) against its own products.

Internet Security Systems is warning about 'Stick' which can reportedly reduce the performance of, or deny service to, many commercial intrusion detection products, including ISS' RealSecure Network Sensor 5.0.

The tool, which has not yet openly available on the Internet, works by flooding intrusion detection systems (IDS) with more information than can be processed.

Stick uses the very straightforward technique of firing numerous attacks from random source IP addresses to purposely trigger IDS events. This technique has been seen before but the implementation used by Stick is far more effective than previous cracker tools which uses similar tricks.

In an alert about the problem ISS admitted: "The IDS system will attempt to keep up with the new flood of events, but if incoming events cross the IDS detection threshold, a DoS might result."

ISS X-Force has verified the existence of a vulnerability in the Windows NT and Windows 2000 versions of RealSecure Network Sensor 5.0 which leaves the product susceptible to an attack by Stick. On both Windows platforms, the event channel becomes congested during the duration of the attack, although the product doesn't actually crash it is thus rendered ineffective.

The Solaris version of Network Sensor is not thought to be affected by the issue.

ISS has developed two fixes for RealSecure Network Sensor that will limit the risk of a Stick attack, and has made more information on the issue available here. ®