Nmap Development mailing list archives
Re: nmap brings CheckPoint Firewall-1 down
From: Dan White <dwhite () securecommercesystems com>
Date: Tue, 14 Jun 2005 17:39:15 -0500 (CDT)
Hi Marc, Did your Nokia Checkpoint FW-1/VPN-1 have SmartDefense turned on? Dan White Secure Commerce Systems ---- Matt Hargett <matt () use net> wrote:
Marc Ruef wrote:Has somebody else seen such a behavior and know how to re-configure FW1, Nessus and/or nmap to get a stable environment for the usual Nessus testing? A possible workaround would be to de-activate nmap/postscanning within the Nessus testing. But this does not eliminate the danger of such a weak installation as it tends to be in place. One of our workaround approach was to optimize the FW1 configuration. First of all we implemented a connection limit to 100 connections per host. This made some really nasty false negatives during the mapping, nmap and Nessus scanning. Furthermore we implemented SYN flood detection to 100 half-open connections. This was able to prevent the full DoS. But partially a timeout could be detected. A full break-down of the firewalls was not possible anymore. False negatives are still given.I saw similar behaviour in several different firewall and VPN products using nmap and isic while working at a job in 1998. There were bugs in the code -- no configuration seemd to help things. In one case, their connection-state table in kernel memory grew unchecked, causing the kernel to run out of nonpaged memory, and resulting in a null pointer reference after kmalloc() started failing. Check out my slides from defcon 7 or 8 about testing, it is still very effective from what I have seen. _______________________________________________ Sent through the nmap-dev mailing list http://cgi.insecure.org/mailman/listinfo/nmap-dev
_______________________________________________ Sent through the nmap-dev mailing list http://cgi.insecure.org/mailman/listinfo/nmap-dev
Current thread:
- nmap brings CheckPoint Firewall-1 down Marc Ruef (Jun 14)
- Re: nmap brings CheckPoint Firewall-1 down Matt Hargett (Jun 14)
- Re: nmap brings CheckPoint Firewall-1 down Dan White (Jun 14)