Re: [Snort-users] Web servers scanning clients!!!



Ahh, so sorry, I interpreted you as asking intently about target_limit, not targets_max.. Which would, really, not matter :)

In any event both scanners_max, and targets_max are at least one order of magnitude greater than the total number of used IPs inside this network. (ie: there's less than 320 active systems/appliances with IP addresses here).

Even during quiescent hours when nobody else is here I can make the alerts fire. Like right now.. yes, there are a couple of servers here, including a DNS server, running amok, but the network is relatively quiet at the moment and I'm the only human at a computer or making any client systems do much. A short run of tcpdump on the snort box showed 52 packets in 19.5 seconds (while I was not browsing the web)


[**] [117:1:1] (spp_portscan2) Portscan detected from 205.206.231.13: 1 targets 61 ports in 7 seconds [**]
12/26-22:31:34.021685 205.206.231.13:80 -> xx.xx.xx.xx:1321
TCP TTL:45 TOS:0x0 ID:8401 IpLen:20 DgmLen:48 DF
***A**S* Seq: 0x685A5A64 Ack: 0xAA737BF0 Win: 0x7E24 TcpLen: 28
TCP Options (4) => MSS: 1404 NOP NOP SackOK

For this simple example I went to http://www.securityfocus.com/ in mozilla (1.2.1, win32), waited 30 seconds for the original connections to time-out (I have a 20 sec timeout set for portscan2), and did a shift-reload twice. Poof, instant alert from 61 connections in a mere 2 page loads. Given that the default is 20, I suspect one load would trigger that level.







At 10:10 PM 12/26/2002 -0500, Jason wrote:


Matt Kettler wrote:
No, this is a port_limit exceeded issue, not a nubmer of targets issue. It doesn't matter how many machines are on my lan, or if the number of them is greater than targets_max. The number of targets in the alert is 1 :)
Are you absolutely sure :-)

I understand the situation completely. Questions are sometimes intended to get information as much as they are intended to get a thought rolling.

[snip rest]


-------------------------------------------------------
This sf.net email is sponsored by:ThinkGeek
Welcome to geek heaven.
http://thinkgeek.com/sf
_______________________________________________
Snort-users mailing list
Snort-users@lists.sourceforge.net
Go to this URL to change user options or unsubscribe:
https://lists.sourceforge.net/lists/listinfo/snort-users
Snort-users list archive:
http://www.geocrawler.com/redir-sf.php3?list=snort-users



questions/problems with archive to: webmaster@mcabee.org
Mail converted by MHonArc 2.5.12