Firewall Wizards mailing list archives
Re: How do you fight an attack in progress?
From: Paul Ferguson <ferguson () cisco com>
Date: Fri, 19 Sep 1997 20:52:19 -0400
At 01:36 PM 9/19/97 -0500, Andy Howard wrote:
The scan itself is not dangerous.... just rattling the door knob. Some Web search and indexing sites do this.... there are some legitimate reasons to get the door knob rattled.
This is a subtle point which is important to understand. For instance, what do you automatically think when your logs report that a udp/161 'scan' is being done on sequential host addresses? Well, if you've seen NOC monkeys haplessly enable SNMP discovery mode (for instance on an HP*OpenView system), then you know what I'm talking about. ;-) The point is that it 'scans' may sometimes not be malicious, but rather the result of some moron somewhere on the opposite side of the planet. And even when it is, you still need to contact them to tell them to 'Cut it out', but it pays to be somewhat intelligent before sounding the alarm By the same token, there is usually a big difference between sequential port scanning (which is almost always malicious in nature) and sequential host scanning, which may be quite legitimate. Another legitimate example, besides the SNMP discovery foobar I mentioned above, is PING'ing hosts within a range of addresses. In fact, this is done on a fairly frequent basis, to determine the scope of address utilization and the growth of the Internet itself. As an aside, see: http://www.nw.com - paul -- Paul Ferguson || || Consulting Engineering || || Herndon, Virginia USA |||| |||| tel: +1.703.397.5938 ..:||||||:..:||||||:.. e-mail: ferguson () cisco com c i s c o S y s t e m s
Current thread:
- How do you fight an attack in progress? Grigorof, Adrian (Sep 19)
- Re: How do you fight an attack in progress? Marcus J. Ranum (Sep 19)
- Re: How do you fight an attack in progress? Erik Van Riper (Sep 19)
- Re: How do you fight an attack in progress? Paul Ferguson (Sep 19)
- Re: How do you fight an attack in progress? Andy Howard (Sep 19)
- Re: How do you fight an attack in progress? Paul Ferguson (Sep 20)
- Re: How do you fight an attack in progress? Neil Readwin (Sep 19)
- Re: How do you fight an attack in progress? John Lines (Sep 23)
- Re: How do you fight an attack in progress? Mark Coleman (Sep 20)
- Re: How do you fight an attack in progress? Joseph S. D. Yao (Sep 22)
- <Possible follow-ups>
- Re: How do you fight an attack in progress? Michele Mullins Jordan - Commercial SE-Sun-McLean VA (Sep 19)
- How do you fight an attack in progress? Grigorof, Adrian (Sep 19)
- Re: How do you fight an attack in progress? Paul Ferguson (Sep 19)
- Re: How do you fight an attack in progress? Rik Harris (Sep 23)