Re: Scanning--more then one side to the argument
From: Shand (shand_at_adelphia.net)
Date: 03/30/05
- Previous message: Michael Pietrzak: "RE: Win32 Firewalls."
- Maybe in reply to: Sherman Hand: "Scanning--more then one side to the argument"
- Next in thread: Steve Fletcher: "RE: Scanning--more then one side to the argument"
- Reply: Steve Fletcher: "RE: Scanning--more then one side to the argument"
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To: "Steve Fletcher" <safletcher@insightbb.com>, <security-basics@securityfocus.com> Date: Wed, 30 Mar 2005 16:16:31 -0500
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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- Previous message: Michael Pietrzak: "RE: Win32 Firewalls."
- Maybe in reply to: Sherman Hand: "Scanning--more then one side to the argument"
- Next in thread: Steve Fletcher: "RE: Scanning--more then one side to the argument"
- Reply: Steve Fletcher: "RE: Scanning--more then one side to the argument"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]
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