Re: [NSE] new scripts and libraries: brute library

[David Fifield <david () bamsoftware com>]

On Fri, Aug 20, 2010 at 07:59:00PM +0200, Patrik Karlsson wrote:
> On 20 aug 2010, at 18.56, David Fifield wrote:
>
> > On Fri, Aug 20, 2010 at 12:11:53AM +0200, Patrik Karlsson wrote:
> > > On 18 aug 2010, at 18.05, David Fifield wrote:
> > > > > So if a socket error occurs we need to report an error back to the engine.
> > > > > If the retry attribute is set using the setRetry on the error object
> > > > > the engine will retry the credential.
> > > > > When max_retries (default 3, can be modified with argument) is
> > > > > reached, the engine aborts.
> > > >
> > > > How does the login method distinguish the two failure modes: (1) access
> > > > denied, and (2) socket error. I want (2) to be retried, but not (1).
> > >
> > > This is really up to the driver, it needs to be able to determine (at
> > > a protocol level) whether the login was denied or if there was a
> > > socket error.
> > > The login method in the Driver the needs to adjust the Error object
> > > appropriately before returning it to the Engine.
> >
> > This is where I'm confused. How do I adjust the Error object to reflect
> > both of the two states? Can you provide code examples?
>
> This is from vnc-brute:
>
>               if ( not(status) and data:match("Too many authentication failures") ) then
>                       local err = brute.Error:new( data )
>                       err:setAbort( true ) -- Aborts the scan
>                       return false, err                       
>               elseif ( not(status) ) then
>                       local err = brute.Error:new( "VNC handshake failed" )
>                       -- This might be temporary, set the retry flag
>                       err:setRetry( true ) -- Signals the engine to retry
>                       return false, err
>               end
>
>               .
>               .
>               .
>
>               -- Return a simple error, no retry needed
>               return false, brute.Error:new( "Incorrect password" ) 
>
>
> ... and to save you an e-mail, I've added it to the top of the brute library and commited it as r19911 :)

Great, thanks, that's exactly what I was looking for. It wasn't obvious
to me that you can return different kinds of Errors by calling setAbort
or setRetry on them.

David Fifield
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