Nmap Development mailing list archives
Re: TCP Split Handshake and Nmap
From: David Fifield <david () bamsoftware com>
Date: Tue, 8 Jun 2010 11:26:43 -0600
On Fri, Jun 04, 2010 at 04:22:55PM +0100, jah wrote:
The attached patch does very little work since the split handshake SYN passes the existing checks for dest port matching a probe source port; it adds a test for the SYN flag right after the test for SYN|ACK for SYN scans.
+ } else if (USI->scantype == SYN_SCAN && tcp->th_flags == TH_SYN) { Just one thing I would change here: + } else if (USI->scantype == SYN_SCAN && (tcp->th_flags & TH_SYN) == TH_SYN) { That way it will work with a SYN|URG or SYN|PSH or something else silly. Putting this test after the SYN|ACK test lets SYN|ACK continue giving the correct reason code.
Adding the reason code was a bit of a headfuck, but I seem to have managed it without breaking anything (a echo request ping still yields an echo-reply as the reason, for instance).
Thanks for taking care with this. The reason codes are way more complicated than they need to be. It's meant to make it easy to look up, say, the reason code for a ICMP code with just an addition, but that's not worth the huge maintenance/understandability problems in my opinion. (Plus all the places that look up the code have to have knowledge of the table's magic structure, spreading the complexity around). A couple of lookup tables from ICMP types/codes to reason codes would be much better. David Fifield _______________________________________________ Sent through the nmap-dev mailing list http://cgi.insecure.org/mailman/listinfo/nmap-dev Archived at http://seclists.org/nmap-dev/
Current thread:
- TCP Split Handshake and Nmap jah (Jun 02)
- what is ER_INITACK? jah (Jun 02)
- Re: TCP Split Handshake and Nmap Fyodor (Jun 03)
- Re: TCP Split Handshake and Nmap Fyodor (Jun 03)
- Re: TCP Split Handshake and Nmap jah (Jun 04)
- Re: TCP Split Handshake and Nmap Fyodor (Jun 07)
- Re: TCP Split Handshake and Nmap jah (Jun 07)
- Re: TCP Split Handshake and Nmap David Fifield (Jun 08)
- Re: TCP Split Handshake and Nmap jah (Jun 08)
- Re: TCP Split Handshake and Nmap David Fifield (Jun 08)
- Re: TCP Split Handshake and Nmap Fyodor (Jun 10)