Snort mailing list archives

Re: RE: RE: flow-portscan really suitable ???


From: BIZOU <bizou () voila fr>
Date: Fri, 5 Mar 2004 11:06:14 +0100 (CET)

hum.... here is my snort.conf (2.1.1). Do you see something wrong ?

# local vars are used in local.rules
var HOME_NET any
var SNMPALLOWED [MANY_IPS]
var WEBONPROXYPORT [MANY_IPS]
var SOCKSCLIENTALLOWED [many_IPS]
var SQUIDCLIENTSALLOWED [MANY_IPS]
var SQUIDSERVALLOWED [MANY_IPS]
var EXTERNAL_NET any
var DNS_SERVERS $HOME_NET
var SMTP_SERVERS $HOME_NET
var HTTP_SERVERS $HOME_NET
var SQL_SERVERS $HOME_NET
var TELNET_SERVERS $HOME_NET
var SNMP_SERVERS $HOME_NET
var HTTP_PORTS 80
var SHELLCODE_PORTS !80
var ORACLE_PORTS 1521
var AIM_SERVERS 
[64.12.24.0/24,64.12.25.0/24,64.12.26.14/24,64.12.28.0/24,64.12.29.0/24,64.12.161.0/24,64.12.163.0/24,205.188.5.0/24,205.188.9.0/24]
var RULE_PATH /etc/snort/rules

#preprocessor flow: stats_interval 0 hash 2

preprocessor frag2

preprocessor stream4: detect_scans, disable_evasion_alerts

preprocessor stream4_reassemble

preprocessor http_inspect: global \
    iis_unicode_map unicode.map 1252 

preprocessor http_inspect_server: server default \
    profile all ports { 80 8080 8180 } oversize_dir_length 500 \
    no_alerts

preprocessor rpc_decode: 111 32771

preprocessor bo

preprocessor telnet_decode

# preprocessor flow-portscan: \
#        talker-sliding-scale-factor 0 \
#        talker-fixed-threshold 0 \
#        talker-sliding-threshold 0 \
#        talker-sliding-window 0 \
#        talker-fixed-window 0 \
#        server-watchnet [SOME_SUBNETS] \
#        scanner-sliding-scale-factor 0.50 \
#        scanner-fixed-threshold 300 \
#        scanner-sliding-threshold 200 \
#        scanner-fixed-window 30 \
#        src-ignore-net [MANY_IPS] \
#        alert-mode all \
#        output-mode pktkludge \
#        tcp-penalties on

preprocessor conversation: allowed_ip_protocols all, timeout 60, max_conversations 3000

preprocessor portscan2: scanners_max 256, targets_max 1024, target_limit 30, port_limit 40, timeout 40

preprocessor portscan2-ignorehosts: MANY_IPS

preprocessor portscan2-ignoreports-from: 80 111 161 21 20 25 11960 443

output alert_prelude: async, classification_file=prelude-classification.config

include classification.config

include reference.config

include $RULE_PATH/local.rules
include $RULE_PATH/bad-traffic.rules
include $RULE_PATH/exploit.rules
include $RULE_PATH/scan.rules
include $RULE_PATH/finger.rules
include $RULE_PATH/ftp.rules
include $RULE_PATH/telnet.rules
include $RULE_PATH/rpc.rules
include $RULE_PATH/rservices.rules
include $RULE_PATH/dos.rules
include $RULE_PATH/ddos.rules
include $RULE_PATH/dns.rules
include $RULE_PATH/tftp.rules
include $RULE_PATH/web-cgi.rules
include $RULE_PATH/web-coldfusion.rules
include $RULE_PATH/web-iis.rules
include $RULE_PATH/web-frontpage.rules
include $RULE_PATH/web-misc.rules
include $RULE_PATH/web-client.rules
include $RULE_PATH/web-php.rules
include $RULE_PATH/sql.rules
include $RULE_PATH/x11.rules
include $RULE_PATH/icmp.rules
include $RULE_PATH/netbios.rules
include $RULE_PATH/misc.rules
include $RULE_PATH/attack-responses.rules
include $RULE_PATH/oracle.rules
include $RULE_PATH/mysql.rules
include $RULE_PATH/snmp.rules
include $RULE_PATH/smtp.rules
include $RULE_PATH/imap.rules
include $RULE_PATH/pop2.rules
include $RULE_PATH/pop3.rules
include $RULE_PATH/nntp.rules
include $RULE_PATH/other-ids.rules
include $RULE_PATH/experimental.rules



And here is what i get when i launch it like that
.....
      Ascii: YES alert: NO
      Double Decoding: YES alert: YES
      %U Encoding: YES alert: YES
      Bare Byte: YES alert: YES
      Base36: OFF
      UTF 8: OFF
      IIS Unicode: YES alert: YES
      Multiple Slash: YES alert: NO
      IIS Backslash: YES alert: NO
      Directory: YES alert: NO
      Apache WhiteSpace: YES alert: YES
      IIS Delimiter: YES alert: YES
      IIS Unicode Map: GLOBAL IIS UNICODE MAP CONFIG
      Non-RFC Compliant Characters: NONE
rpc_decode arguments:
    Ports to decode RPC on: 111 32771 
    alert_fragments: INACTIVE
    alert_large_fragments: ACTIVE
    alert_incomplete: ACTIVE
    alert_multiple_requests: ACTIVE
telnet_decode arguments:
    Ports to decode telnet on: 21 23 25 119 
Segmentation fault





You need to have conversation segment available as well from the
original snort.conf.

-Doug

-----Original Message-----
From: BIZOU [mailto:bizou () voila fr] 
Sent: Thursday, March 04, 2004 11:50 AM
To: snort-users () lists sourceforge net
Subject: Re: RE: [Snort-users] flow-portscan really suitable ???


Well, i'd like to use portscan2 again, but when i try to use it in the
config and disable flow-portscan, i receive a segfault just when snort
try to load conversation/portscan2. And i've seen somewhere else that
portscan2 was disabled since 2.1.1 (although it is still present in
src/preprocessor/). Can you confirm if it's really still available ? and
in this case, is there a special statement to insert in the config ?
Thanks




You can still use Portscan2 thankfully by just copying back the 
sections from an old config. I have to agree here about flow-portscan.

Portscan2 works nicely for me an rarely shows false positives. I still

haven't seen anything from flow-portscan besides false positives and 
considering
that- even when it shows the false positives, it doesn't report any
useful data (with msg or pktkludge). I've also only seen responses
from
people saying, "Use pktkludge, it's in the documentation." Well, I
have,
and it still doesn't produce any useful data anywhere that I can see
no
matter what settings I put for anything. 

My question is this... Is anyone using flow-portscan effectively and 
getting results such that you can see that a system is scanning your 
hosts for port 25, etc.? If so, can you post your settings for this? 
Neither myself nor my colleagues who have used Snort for years have 
been able to get this to work at all. We are all concerned that 
portscan2 will be removed, and then we will no longer be able to see 
any scanning activity using Snort.

-Doug

-----Original Message-----
From: BIZOU [mailto:bizou () voila fr]
Sent: Thursday, March 04, 2004 11:10 AM
To: snort-users () lists sourceforge net
Subject: [Snort-users] flow-portscan really suitable ???


Hi,

I've been working on snort 2.1.1 for a few days. I was previously with

snort 2.0.5. I had to change my portscan2 configuration into 
flow-portscan and ... well i dislike it Indeed, i tuned my portscan2 
preprocessor with scanner-max 256, target_max 1024, target_limit 30, 
port_limit 40, timeout 40 and it was quite fine. I used 
portscan2-ignorehost and ignore-port too. I catched MydoomB scans, 
Blaster.C or B (don't remember) scans, nmap scan.... Now with 
flow-portscan, i have nothing except flase positive scans I'm managing

6 NIDS in a wide environment so i cannot define a HOME_NET or wathever

defined variable

When i watched at my prelude reporting GUI this morning (i use a 
prelude framework for alerting) i only saw false scan alerts. I tried 
to configure flow-portscan in several way, i cannot succeed in having 
correct results

So please,
1 - tell me that it wil be possible again to use portscan2 in future
releases 2 - Tell me a way to configure correctly and simply
flow-portscan (without a learning time ) 3 - Tell me a way to add
flow-portscan ignore port from 4 - Tell me that destination port will
be
present in pktkludge soon


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This SF.Net email is sponsored by: IBM Linux Tutorials
Free Linux tutorial presented by Daniel Robbins, President and CEO of
GenToo technologies. Learn everything from fundamentals to system
administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click
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This SF.Net email is sponsored by: IBM Linux Tutorials
Free Linux tutorial presented by Daniel Robbins, President and CEO of
GenToo technologies. Learn everything from fundamentals to system
administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click
_______________________________________________
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