Bugtraq mailing list archives
Re: Checkpoint SYN DoS Vulnerability
From: Chris Brenton <cbrenton () chrisbrenton org>
Date: Tue, 16 May 2006 16:14:09 -0400
On Tue, 2006-05-16 at 11:09 -0400, sanjay naik wrote:
When a scan is intiated from the Inside interface of Checkpoint firewall, the firewall responds with bogus information intermittently.
Sounds like you are triggering the SYN flood protection. Typically the firewall will respond with a SYN/ACK to ensure the source is not just generating a SYN flood. If you close the handshake, the connection is passed through to the target host if it is permitted in the rules. If not, the connection is simply deleted from the state table and ignored. Not sure why you are calling this a DoS as it does not sound like regular connectivity is being effected. The exception would be if you generated enough bogus SYN packets to fill up the state table so legit connections could not get through. I seem to remember Lance posting info about that to this list 4-5 years ago.
In both cases, the scans results were inconsistent. Both SYN and ACK scans had similar issues.
IMHO this is a feature. I would certainly rather see a port scanner receiving bogus results rather than accurate info that would assist in a compromise. Make them work a bit harder and earn it. ;-) HTH, Chris
Current thread:
- Checkpoint SYN DoS Vulnerability sanjay naik (May 16)
- Re: Checkpoint SYN DoS Vulnerability Pawel Worach (May 16)
- Re: Checkpoint SYN DoS Vulnerability sanjay naik (May 16)
- Re: Checkpoint SYN DoS Vulnerability Bojan Zdrnja (May 17)
- Re: Checkpoint SYN DoS Vulnerability Jim Clausing (May 22)
- Re: Checkpoint SYN DoS Vulnerability Erick Mechler (May 18)
- Re: Checkpoint SYN DoS Vulnerability Bojan Zdrnja (May 22)
- Re: Checkpoint SYN DoS Vulnerability sanjay naik (May 16)
- Re: Checkpoint SYN DoS Vulnerability Pawel Worach (May 16)
- Re: Checkpoint SYN DoS Vulnerability sanjay naik (May 18)
- Re: Checkpoint SYN DoS Vulnerability Niranjan S Patil (May 24)
- <Possible follow-ups>
- Re: Checkpoint SYN DoS Vulnerability sanjay naik (May 17)
- Re: Re: Checkpoint SYN DoS Vulnerability jrh57 (May 18)
- RE: Checkpoint SYN DoS Vulnerability Sterling, Chuck (May 18)
- Re: Checkpoint SYN DoS Vulnerability sanjay naik (May 18)