Re: Scanning--more then one side to the argument

["Shand" <shand () adelphia net>]

Example of customer scan

nmap -sV -P0 -p 1-

Starting nmap 3.50 ( http://www.insecure.org/nmap/ ) at 2005-03-30 16:59 EST
Interesting ports on
(The 65522 ports scanned but not shown below are in state: closed)
PORT      STATE    SERVICE      VERSION
80/tcp    filtered http
135/tcp   filtered msrpc
136/tcp   filtered profile
137/tcp   filtered netbios-ns
138/tcp   filtered netbios-dgm
139/tcp   filtered netbios-ssn
445/tcp   filtered microsoft-ds
5000/tcp  open     upnp         Microsoft Windows UPnP
5241/tcp  open     unknown
7177/tcp  open     unknown
8031/tcp  open     unknown
9491/tcp  open     unknown
27374/tcp filtered subseven

Nmap run completed -- 1 IP address (1 host up) scanned in 438.716 seconds


Now I see this as a issue?

Other don't?

The filtered ones are filtered by us.

The others they have open? ( Not firewall?) ( No security?)

Sherman


----- Original Message ----- 
From: "Steve Fletcher" <safletcher () insightbb com>
To: "'Shand'" <shand () adelphia net>; <security-basics () securityfocus com>
Sent: Wednesday, March 30, 2005 3:41 PM
Subject: RE: Scanning--more then one side to the argument


> That would depend on the port and what function it serves.  For example,
> you
> might show port 25 as open because they have an SMTP server and it is not
> behind a firewall.
>
> Here is a definition of the different states, straight from the nmap man
> page:
>
> "The state is either "open", "filtered", or "unfiltered".  Open
> means that       the target machine will accept() connections on that
> port.  Filtered means that a firewall, filter, or other network obstacle
> is
> covering the port and preventing nmap from determining whether the port
> is open.  Unfiltered means that the port is known by nmap to  be
> closed  and  no firewall/filter seems to be interfering with nmap's
> attempts to determine this.  Unfiltered ports are the common case and are
> only shown when most of the scanned ports are in the filtered state."
>
> Hope this helps.
>
> Steve Fletcher
> MCSE (NT4/Win2k), MCSE: Security (Win2k), HP Master ASE, CCNA, Security+
> safletcher () insightbb com
>
> -----Original Message-----
> From: Shand [mailto:shand () adelphia net]
> Sent: Wednesday, March 30, 2005 2:33 PM
> To: Steve Fletcher; security-basics () securityfocus com
> Subject: Re: Scanning--more then one side to the argument
>
> External scans.
>
> Against customer using our internet service.
>
> Does a port have to show as "open" or can they for usability show only as
> filtered, closed?
>
> Thoughts?
>
> Shand
>
>
>
>
> ----- Original Message ----- 
> From: "Steve Fletcher" <safletcher () insightbb com>
> To: "'Sherman Hand'" <shand () adelphia net>;
> <security-basics () securityfocus com>
> Sent: Wednesday, March 30, 2005 3:18 PM
> Subject: RE: Scanning--more then one side to the argument
>
>
> > I have a question regarding this.  Are you talking about doing an external
> > scan or an internal scan?  I assume an external, because an internal scan
> > should show a LOT of open ports.
> >
> > I would say that any open port POTENTIALLY could be a security issue
> > waiting
> > to happen, but common sense dictates that some ports must be open for
> > usability reasons.  Plus, if you're going to follow this line of thought,
> > the fact that the systems are connected to the Internet AT ALL poses a
> > potential risk.  Or, just being networked could be a risk.  Or, being
> > powered on poses a potential risk.
> >
> > So, based on this, sure it COULD be a security risk waiting to happen,
> > but
> > more information needs to be gathered to determine the true extent of the
> > risk.  And, it must be reevaluated at regular intervals to catch new
> > issues
> > that might have come up since the last scan.  What is safe now might not
> > be
> > 6 months from now.
> >
> > Hope this helps.
> >
> > Steve Fletcher
> > MCSE (NT4/Win2k), MCSE: Security (Win2k), HP Master ASE, CCNA, Security+
> > safletcher () insightbb com
> >
> > -----Original Message-----
> > From: Sherman Hand [mailto:shand () adelphia net]
> > Sent: Wednesday, March 30, 2005 5:05 PM
> > To: security-basics () securityfocus com
> > Subject: Scanning--more then one side to the argument
> >
> >
> >
> > There has been a on going discussion about the scanning results on our
> > customers.
> >
> > Thought one says that "any" port on a standard nmap, showing as "open" is
> > a
> > security risk.
> >
> > Thought two says, no since some things need to show in a state of open.
> >
> > Should we be stating that through proactive scan, when we find any port
> > showing as open, that it is a security issue waiting to happen?
> >
> > Or only if we can show a issue?
> >
> > Thoughts?
> >
> > Shand



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