#!/bin/bash #Copyright 2003 William Stearns #Released under the GPL. #ZZZZ Check Me and MyVersion Me='snort-policy' 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="SID555" $Ipt -A $Me -p tcp --sport 23 -m string --string '"WinGate>"' $Tail # '"POLICY WinGate telnet server response"' arachnids,366 cve,CAN-1999-0657 classtype:misc-activity sid:555 LogAs="SID560" $Ipt -A $Me -p tcp -m state --state ESTABLISHED -m string --string '"RFB 0"' --string '".0"' $Tail # '"POLICY VNC server response"' classtype:misc-activity sid:560 LogAs="SID566" $Ipt -A $Me -p udp --dport 5632 -m string --string '"ST"' $Tail # '"POLICY PCAnywhere server response"' arachnids,239 classtype:misc-activity sid:566 LogAs="SID567" $Ipt -A $Me -p tcp --sport 25 -m string --string '"550 5.7.1"' $Tail # '"POLICY SMTP relaying denied"' url,mail-abuse.org/tsi/ar-fix.html arachnids,249 classtype:misc-activity sid:567 LogAs="SID568" $Ipt -A $Me -p tcp --dport 9100 -m string --string '"@PJL RDYMSG DISPLAY ="' $Tail # '"POLICY HP JetDirect LCD modification attempt"' classtype:misc-activity bugtraq,2245 arachnids,302 sid:568 LogAs="SID510" $Ipt -A $Me -p tcp --dport 9000:9002 -m string --string '"@PJL RDYMSG DISPLAY ="' $Tail # '"POLICY HP JetDirect LCD modification attempt"' classtype:misc-activity bugtraq,2245 arachnids,302 sid:510 LogAs="SID1429" $Ipt -A $Me -s 63.251.224.177 -d $HOME_NET $Tail # '"POLICY poll.gotomypc.com access"' url,www.gotomypc.com/help2.tmpl classtype:misc-activity sid:1429 LogAs="SID1846" $Ipt -A $Me -p tcp --dport 5800:5802 -m string --string '"/vncviewer.jar"' $Tail # '"POLICY vncviewer Java applet download attempt"' nessus,10758 classtype:misc-activity sid:1846 LogAs="SID1445" $Ipt -A $Me -p tcp --dport 21 -m string --string '"RETR"' --string '"file_id.diz"' $Tail # '"POLICY FTP file_id.diz access possible warez site"' nocase-ignored nocase-ignored classtype:suspicious-filename-detect sid:1445 LogAs="SID543" $Ipt -A $Me -p tcp --dport 21 -m string --string '"STOR"' --string '"1MB"' $Tail # '"POLICY FTP 'STOR 1MB' possible warez site"' nocase-ignored nocase-ignored classtype:misc-activity sid:543 LogAs="SID544" $Ipt -A $Me -p tcp --dport 21 -m string --string '"RETR"' --string '"1MB"' $Tail # '"POLICY FTP 'RETR 1MB' possible warez site"' nocase-ignored nocase-ignored classtype:misc-activity sid:544 LogAs="SID546" $Ipt -A $Me -p tcp --dport 21 -m string --string '"CWD "' $Tail # '"POLICY FTP 'CWD ' possible warez site"' nocase-ignored classtype:misc-activity sid:546 LogAs="SID547" $Ipt -A $Me -p tcp --dport 21 -m string --string '"MKD "' $Tail # '"POLICY FTP 'MKD ' possible warez site"' nocase-ignored classtype:misc-activity sid:547 LogAs="SID548" $Ipt -A $Me -p tcp --dport 21 -m string --string '"MKD ."' $Tail # '"POLICY FTP 'MKD .' possible warez site"' nocase-ignored classtype:misc-activity sid:548 LogAs="SID545" $Ipt -A $Me -p tcp --dport 21 -m string --string '"CWD"' --string '"/ "' $Tail # '"POLICY FTP 'CWD / ' possible warez site"' nocase-ignored classtype: misc-activity sid:545 LogAs="SID554" $Ipt -A $Me -p tcp --dport 21 -m string --string '"MKD"' --string '"/ "' $Tail # '"POLICY FTP 'MKD / ' possible warez site"' nocase-ignored classtype:misc-activity sid:554 LogAs="SID2040" $Ipt -A $Me -p udp --dport 49 -m string --string '"€"' --string '""' $Tail # '"POLICY xtacacs login attempt"' classtype:misc-activity sid:2040 LogAs="SID2042" $Ipt -A $Me -p udp --sport 49 -m string --string '"€"' --string '""' $Tail # '"POLICY xtacacs accepted login response"' classtype:misc-activity sid:2042 LogAs="SID1771" $Ipt -A $Me -p udp --dport 500 -m string --string '"ˆ \\P\$€€€€€ Q€\$€€€€€ Q€"' $Tail # '"POLICY IPSec PGPNet connection attempt"' classtype:protocol-command-decode sid:1771 ;; 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