Re: Well known scan-attack
- From: "Jim Harrison" <jim@xxxxxxxxxxxx>
- To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx>
- Date: Wed, 29 Oct 2003 08:36:33 -0800
Those are typically "late" response packets.
This happens when the remote host is overloaded and is on the tail-end of
the maximum response time for a protocol.
ISA regards RFCs as the "bibles" of networking behavior.
If anyone violates one or more of those references, ISA will cry "foul".
You can tweak the alert trigger levels in IP Packet Filtering to reduce the
number of false positives for some "attacks", but it will have no effect on
a return packet from a session that ISA considers "closed".
..some alerts are just noise...
Jim Harrison
MCP(NT4, W2K), A+, Network+, PCG
http://www.microsoft.com/isaserver
http://isaserver.org/Jim_Harrison
http://isatools.org
Read the help, books and articles!
----- Original Message -----
From: "Chad Roush" <croush@xxxxxxxxxxx>
To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx>
Sent: Wednesday, October 29, 2003 08:27
Subject: [isalist] Re: Well known scan-attack
http://www.ISAserver.org
I too am getting this messages. It's nice to know it is nothing to
worry about.
Another one I am getting is port scans being reported from IP's
belonging to my ISP's DNS servers.
Any suggestions on what to do to clean these up? It would be nice to
reduce the number of irrelevant
notifications I am getting.
Thanks,
Chad
-----Original Message-----
From: Jim Harrison [mailto:jim@xxxxxxxxxxxx]
Sent: Wednesday, October 29, 2003 8:20 AM
To: [ISAserver.org Discussion List]
Subject: [isalist] Re: Well known scan-attack
http://www.ISAserver.org
This is a common script kiddie tool.
It's designed to send your machine into a death-spiral of
self-referencing responses, since the source and destination IPs will
always alternate between the local machine (127.0.0.1 and your external
IP).
ISA blocks it as spoofed, since it was received on a network interface.
127.0.0.1 is invalid except in the memory-mapped network inside the
machine.
Jim Harrison
MCP(NT4, W2K), A+, Network+, PCG
http://isaserver.org/Jim_Harrison/
http://isatools.org
Read the help / books / articles!
On Wed, 29 Oct 2003 13:52:27 +0300
"Andrey Silkin" <silkin@xxxxxx> wrote:
http://www.ISAserver.org
Hi all ! I Some days ago I have received strange notification : ISA
Server detected a well-known port scan attack from Internet Protocol
(IP) address 127.0.0.1. A well-known port is any port in the range of
1-2048. I don't understand how can it be ? 127.0.0.1 - is the local
private address ! It is impossible that somebody scaned my my server
from himself . Did somebody have the same notification ?
Best Regards
Andrey Silkin
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