#!/bin/bash #Copyright 2003 William Stearns #Released under the GPL. #ZZZZ Check Me and MyVersion Me='snort-info' MyVersion='20031125' #DefaultActions='' [ -r /etc/firebricks/firebricks.conf ] && . /etc/firebricks/firebricks.conf [ -r /etc/firebricks/$Me.conf ] && . /etc/firebricks/$Me.conf [ -r ${FBLibDir:-'/usr/lib/firebricks/'}/firebrickslib ] && . ${FBLibDir:-'/usr/lib/firebricks/'}/firebrickslib if [ -z "$FBLibVer" ]; then echo 'It looks like firebrickslib was not loaded, why? Exiting' >&2 exit 1 fi for OneTask in $Tasks ; do case "$OneTask" in link) $IptablesBin -N $Me >/dev/null 2>&1 #ZZZZ try to restrict the following three to only send down what the chain needs to inspect. $IptablesBin $AppIn INPUT -i \! lo -j $Me $IptablesBin $AppIn FORWARD -j $Me $IptablesBin $AppIn OUTPUT -j $Me ;; unlink) #ZZZZ Make the same changes as above (such as "-p tcp"), but if you cut and paste, note "$AppIn" is now "-D" $IptablesBin -D INPUT -i \! lo -j $Me $IptablesBin -D FORWARD -j $Me $IptablesBin -D OUTPUT -j $Me $IptablesBin -X $Me >/dev/null 2>&1 ;; create) echo "Starting $Me" >&2 FlushOrNewChain $Me LogAs="SID488" $Ipt -A $Me -p tcp --sport 80 -m string --string '"Connection closed by foreign host"' $Tail # '"INFO Connection Closed MSG from Port 80"' nocase-ignored classtype:unknown sid:488 LogAs="SID490" $Ipt -A $Me -p tcp --dport 25 -m string --string '"BattleMail"' $Tail # '"INFO battle-mail traffic"' classtype:unknown sid:490 LogAs="SID491" $Ipt -A $Me -p tcp --sport 21 -m string --string '"530 Login "' $Tail # '"INFO FTP Bad login"' nocase-ignored classtype:bad-unknown sid:491 LogAs="SID492" $Ipt -A $Me -p tcp --sport 23 -m string --string '"Login failed"' $Tail # '"INFO TELNET Bad Login"' nocase-ignored classtype:bad-unknown sid:492 LogAs="SID1251" $Ipt -A $Me -p tcp --sport 23 -m string --string '"Login incorrect"' $Tail # '"INFO TELNET Bad Login"' nocase-ignored classtype:bad-unknown sid:1251 LogAs="SID493" $Ipt -A $Me -p tcp -m string --string '"Welcome!psyBNC@lam3rz.de"' $Tail # '"INFO psyBNC access"' classtype:bad-unknown sid:493 ;; destroy) echo "Stopping $Me" >&2 DestroyChain $Me ;; renamechain) TempChain="$Me-$RANDOM" echo "Replacing existing rules in $Me with new rules" >&2 $IptablesBin -E $Me $TempChain ;; replacelinks) if [ -z "$TempChain" ]; then echo "No temporary chain to relink in $Me replacelinks, replace operation incomplete." >&2 elif ! $IptablesBin -L $Me -n >/dev/null 2>&1 ; then echo "No $Me chain in $Me, replace operation incomplete." >&2 elif ! $IptablesBin -L $TempChain -n >/dev/null 2>&1 ; then echo "No $TempChain chain in $Me, replace operation incomplete." >&2 elif [ "`$IptablesBin -L INPUT -n --line-numbers | grep $TempChain | wc -l`" -ne 1 ]; then echo "Too few/many references to $TempChain in INPUT in $Me replacelinks, replace operation incomplete." >&2 elif [ "`$IptablesBin -L FORWARD -n --line-numbers | grep $TempChain | wc -l`" -ne 1 ]; then echo "Too few/many references to $TempChain in FORWARD in $Me replacelinks, replace operation incomplete." >&2 elif [ "`$IptablesBin -L OUTPUT -n --line-numbers | grep $TempChain | wc -l`" -ne 1 ]; then echo "Too few/many references to $TempChain in OUTPUT in $Me replacelinks, replace operation incomplete." >&2 else #ZZZZ Place the same criteria you used in link/unlink above in the following three lines. #ZZZZ Criteria should go just in front of "-j $Me" $IptablesBin -R INPUT `$IptablesBin -L INPUT -n --line-numbers | grep $TempChain | awk '{print $1}'` -i \! lo -j $Me $IptablesBin -R FORWARD `$IptablesBin -L FORWARD -n --line-numbers | grep $TempChain | awk '{print $1}'` -j $Me $IptablesBin -R OUTPUT `$IptablesBin -L OUTPUT -n --line-numbers | grep $TempChain | awk '{print $1}'` -j $Me DestroyChain $TempChain unset TempChain fi ;; status) if $IptablesBin -L $Me -n >/dev/null 2>&1 ; then echo "$Me created" >&2 else echo "$Me destroyed" >&2 fi ;; version) echo "$Me $MyVersion, firebrickslib $FBLibVer" >&2 ;; help) DefaultHelp #ZZZZ Please change the text to appropriate help text for this module. You should #ZZZZ cover what the module does, if it's generally safe to use, and under what #ZZZZ conditions it should not be used. Please replace the lines between the two #ZZZZ EOTEXT lines with your own. cat <&2 The $Me module puts in some blocks for fragmented icmp packets (illegal) and address mask and timestamp requests and replies. At best, these are uncommon and are used in network mapping. These rules should be safe to use on any network. EOTEXT ;; *) echo "Unknown action $Action in $Me, no action taken." >&2 ;; esac done