RE: SF, SFP scans?

[joe.pepin () guardent com]

Thanks!

While the -sF works better against Linux, -sS works better (quicker) against
Windows (and therefor probably BSD as well ;)

Windows will happily send a SYNACK to an 0xEB.

/joe
.


>  -----Original Message-----
>  From: Fyodor [mailto:fyodor () insecure org]
>  Sent: Wednesday, October 30, 2002 1:16 PM
>  To: Joe Pepin
>  Cc: nmap-dev () insecure org
>  Subject: Re: SF, SFP scans?
>  
>  
>  On Wed, Oct 30, 2002 at 12:27:11PM -0500, 
>  joe.pepin () guardent com wrote:
>  
>  > I would like to modify nmap such that I can do a modified 
>  SYN scan where I
>  > have the FIN or PUSH (or even URG, RST, X and Y) bits set. 
>   Stacks all over
>  > the place are accepting packets like SFPUXY to start 
>  sessions, and I want to
>  > see if any firewalls which pretend to be stateful will 
>  allow these through.
>  > 
>  > I was able to kind-of do this the cheap, cheap, dirty way 
>  by modifying
>  > netinet/tcp.h, but that's obviously ugly for lots of reasons and I
>  > was
>  
>  Dear lord, that is ugly :).  But I agree that specifying arbitrary
>  flag values can be useful.  It may not be documented, but recent
>  versions of Nmap have a 'scanflags' options for doing this.  For
>  example, you can do a SYN|FIN scan as follows:
>  
>  felix/home/fyodor#nmap -sS --scanflags SINFIN -p20-25 db
>  
>  Starting nmap V. 3.10ALPHA3 ( www.insecure.org/nmap/ )
>  Interesting ports on db.yuma.net (192.168.0.4):
>  (The 5 ports scanned but not shown below are in state: closed)
>  Port       State       Service
>  22/tcp     filtered    ssh                     
>  
>  Nmap run completed -- 1 IP address (1 host up) scanned in 
>  2.288 seconds
>  
>  Only the "normal" flag names are supported, but you can provide a
>  numerical argument to get at "X" and "Y".
>  
>  The way Linux reacts to SYN|FIN packets, it is really more of a FIN
>  scan.  So better results come from treating it that way:
>  
>  felix/home/fyodor#nmap -sF --scanflags SINFIN -p20-25 db
>  
>  Starting nmap V. 3.10ALPHA3 ( www.insecure.org/nmap/ )
>  Interesting ports on db.yuma.net (192.168.0.4):
>  (The 5 ports scanned but not shown below are in state: closed)
>  Port       State       Service
>  22/tcp     open        ssh                     
>  
>  Nmap run completed -- 1 IP address (1 host up) scanned in 
>  1.594 seconds
>  
>  Cheers,
>  Fyodor
>  

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