Re: Ncrack Error.

[ithilgore <ithilgore.ryu.l () gmail com>]

David Fifield wrote:
> On Fri, Aug 21, 2009 at 11:27:42AM +0300, ithilgore wrote:
> > Gallagher Chris wrote:
> > > Please see the listing:
> > > ============================================
> > > W:\CG\ncrack>ncrack 172.16.251.1-100:22,CL=1,at=1 -oN scan251.txt -v
> > > -d10
> > > Warning: File ./default.usr exists, but Ncrack is using C:\Program
> > > Files\Ncrack\lists\default.usr for security and consistency reasons. Set
> > > NCRACKDIR=. to give
> > > priority to files in your local directory (may affect the other data
> > > files too).
> > > Fetchfile found C:\Program Files\Ncrack\lists\default.usr
> > > Fetchfile found C:\Program Files\Ncrack\lists\default.pwd
> > >
> > > Starting Ncrack 0.01ALPHA ( http://ncrack.org ) at 2009-08-20 13:59 GMT
> > > Daylight Time
> > >
> > > ssh://172.16.251.1:22 Initiating new Connection
> > ....
> > > ssh://172.16.251.96:22 pushed to list FULL
> > > ssh://172.16.251.64:22 pushed to list FULL
> > > Assertion failed: bytesleft > 0, file .\src\nsock_core.c, line 474
> > >
> > > This application has requested the Runtime to terminate it in an unusual
> > > way.
> > > Please contact the application's support team for more information.
> > >
> > > ==============================================================
> > > Thanks for the tool, it looks very promising.
> > > Good luck with the future development.
> > Hello Chris and thanks for the bug report.
> > Since I wasn't able to reproduce the error in my Windows XP SP3 box, could you provide some
> > additional info about the attacked systems and your running host?
>
> That assertion will be tripped when you do a zero-byte nsock_write. The
> assertion arguably shouldn't be there, but if you're looking for the
> cause you can try looking for zero-byte writes.

Indeed, I have seen where that assertion is triggered in nsock and I am guessing that a possible
cause was that the Diffie-Hellman algorithm required by the SSH server he was attacking, isn't yet implemented
in the opensshlib. This has already been reported by jah in the past and I had deduced that the cause
was that. Hopefully, I am planning to implement this extension into opensshlib in the near future, so
this error will be eradicated.

Cheers,
ithilgore

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