RE: Active response... some thoughts.

On Mon, 2003-01-27 at 19:26, Kohlenberg, Toby wrote:

> Actually, TCP resets don't work in many cases- for instance any

In regards to firewall/router reconfig:
Yeah, the damage is done and reconfiguring firewalls don't help 'prevent' that attack, but they can help 'contain' that attack. For example, the firewall can be reconfigured to deny any traffic to and from that attacked device. While in this worm scenario it only prevents the infected host from flooding the Internet, and perhaps internal network, it doesn't prevent other infected hosts on the local segment from flooding out (unless your IDS/firewall tandem is configured in a smart way1), it does work very well on normal backdoor and bo attacks. Even in this scenario the host gets compromised, but the connection to the attacker is then cut off by the firewall and the rooted system is contained through firewall rules.

Regards,
Frank

[1] Smart way could be denying all packets of the same service crossing the firewall. That would prevent other, locally infected, hosts from flooding out.

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