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#!/bin/sh |
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#--------------------------------------------------------------------- |
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#- Adjusting net filter updater daemon |
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#- rabit@netfrag.org, 01.11.2004 |
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I='$Id: anfud.sh,v 1.1 2004/11/12 08:05:09 rabit Exp $' |
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#--------------------------------------------------------------------- |
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#- Functions: |
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|
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# Syntax: dropaddress <IP_address> |
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# |
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dropaddress() { |
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local IP LogMsg RegEx RuleCount |
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|
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if [ -n "$EXCLUDE" ]; then |
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for IP in $EXCLUDE; do |
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case $1 in |
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($IP) |
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logmessage "Ignoring excluded address '$1'." |
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return 1 |
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;; |
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esac |
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done |
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fi |
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|
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RegEx='DROP.*'$1 |
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RuleCount=`iptables -L INPUT -n | egrep $RegEx | wc -l` |
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|
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if [ $RuleCount == 0 ]; then |
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|
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if [ "$PRETEND" == 1 ]; then |
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logmessage "(PRETEND) Dropping rule for address '$1' now would be inserted." |
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else |
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iptables -I INPUT -s $1 -j DROP |
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|
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LogMsg="Dropping rule for address '$1' has been inserted." |
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logmessage "$LogMsg" |
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|
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[ -n "$LOG_DROPPED" ] && syslogwarning "$LogMsg" |
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fi |
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|
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else |
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logmessage "Address '$1' already gets dropped by $RuleCount rule(s). Doing nothing." |
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fi |
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|
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return |
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} |
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|
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# Syntax: echo_log [<Message>] |
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# |
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echo_log() { |
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[ -n "$LOGTARGET" ] && echo $1 >>$LOGTARGET |
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|
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return $? |
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} |
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|
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# Syntax: end [<ExitVal>] |
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# |
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end() { |
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ExitVal=${1:-0} |
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|
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logmessage "Closing session. Exit code is '$ExitVal'." |
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|
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exit $ExitVal |
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|
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return |
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} |
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|
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# Syntax: includeconf |
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# |
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includeconf() { |
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# If existant, include the 'anfud.conf' file: |
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[ -e /etc/anfud.conf ] && source /etc/anfud.conf |
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|
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return $? |
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} |
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|
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# Syntax: init |
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# |
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init() { |
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# Include the configuration file: |
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includeconf |
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|
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# Set the default output log target: |
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[ -z "$LOGTARGET" ] && LOGTARGET=/var/log/anfud.log |
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|
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echo_log # Before starting, output a blank line. |
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logmessage "Session started ($A)." |
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|
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return |
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} |
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|
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# Syntax: logmessage "<Message>" |
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# |
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logmessage() { |
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echo_log "`date +'%b %e %H:%M:%S'` $N[$$]: $1" |
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|
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return $? |
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} |
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|
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# Syntax: syslogwarning "<Message>" |
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# |
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syslogwarning() { |
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logger -p warning -t $N[$$] $1 |
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|
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return $? |
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} |
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|
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#--------------------------------------------------------------------- |
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#- Signal trapping: |
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|
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trap 'logmessage "Recieved signal 1 (SIGHUP)."; end' 1 |
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trap 'logmessage "Recieved signal 2 (SIGINT)."; end' 2 |
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trap 'logmessage "Recieved signal 3 (SIGQUIT)."; end' 3 |
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#trap 'logmessage "Recieved signal 4 (SIGILL)."; end' 4 |
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#trap 'logmessage "Recieved signal 6 (SIGABRT)."; end' 6 |
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trap 'logmessage "Recieved signal 9 (SIGKILL)."; end' 9 |
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trap 'logmessage "Recieved signal 15 (SIGTERM)."; end' 15 |
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|
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#--------------------------------------------------------------------- |
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#- Constants: |
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|
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# Extract the basename: |
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N=$(basename $0) |
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|
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# Format the CVS ID line: |
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|
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I=${I:5} |
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|
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if [ -n "$I" ]; then |
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#while read Name Ver Date Time User Exp; do |
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# A="${Name/,v} v$Ver by $User ($Date, $Time)" |
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#done < <(echo $I) |
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A=$I |
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else |
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A="No CVS ID yet" |
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fi |
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|
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#- Match masks: |
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|
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# Example lines from '/var/log/auth.log' where SSH login failed: |
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#"Jan 1 00:00:00 machine sshd[1000]: Illegal user admin from 127.0.0.1" |
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#"Jan 1 00:00:00 machine sshd[1000]: Failed password for root from 127.0.0.1 port 30000 ssh2" |
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#"Jan 1 00:00:00 machine sshd[1000]: error: PAM: Authentication failure for root from 127.0.0.1" |
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|
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# Match mask for illegal SSH user login attempt: |
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MatchP1='* sshd*: Illegal user *' |
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|
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# Match masks for SSH logins w/ failed password: |
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MatchN2='* sshd*: Failed * for illegal user * from *' |
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MatchP2='* sshd*: Failed password for * from *' |
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|
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# Match mask for SSH logins w/ incorrect password: |
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MatchN3='* sshd*: error: PAM: Authentication failure for illegal user * from *' |
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MatchP3='* sshd*: error: PAM: Authentication failure for * from *' |
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|
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# Example lines from '/var/log/auth.log' where FTP login failed: |
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#"Jan 1 00:00:00 machine ftpd[17986]: FTP LOGIN FAILED FROM host.domain, root" |
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|
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MatchFTP_P1='* ftpd*: FTP LOGIN FAILED FROM *, *' |
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|
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#--------------------------------------------------------------------- |
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#- Initialise: |
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|
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init |
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|
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#--------------------------------------------------------------------- |
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#- Default parameters: |
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|
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# The log file to be scanned for intrusion attempts: |
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# (default: "SCANLOG=/var/log/syslog") |
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[ -z "$SCANLOG" ] && [ -e /var/log/syslog ] && SCANLOG=/var/log/syslog |
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|
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# On start seek and parse log file from beginning: |
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# (default: "SEEKSTART=1") |
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[ -z "$SEEKSTART" ] && SEEKSTART=1 |
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|
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# Follow the scan log file: |
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# (default: "LOGFOLLOW=1") |
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[ -z "$LOGFOLLOW" ] && LOGFOLLOW=1 |
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|
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# Time between log file scans (in seconds): |
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# (default: "INTERVAL=1") |
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[ -z "$INTERVAL" ] && INTERVAL=1 |
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|
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# Drop when illegal SSH login username: |
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# (default: "DROP_SSH_ILLEGALUSER=1") |
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[ -z "$DROP_SSH_ILLEGALUSER" ] && DROP_SSH_ILLEGALUSER=1 |
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|
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# Drop when FTP login failed: |
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# (default: "DROP_FTP_FAILEDLOGIN=1") |
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[ -z "$DROP_FTP_FAILEDLOGIN" ] && DROP_FTP_FAILEDLOGIN=1 |
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|
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# Log address dropping to the system log: |
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# (default: "LOG_DROPPED=1") |
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[ -z "$LOG_DROPPED" ] && LOG_DROPPED=1 |
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|
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# Pretend operation(s) (parse only): |
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# (default: "PRETEND=0") |
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[ -z "$PRETEND" ] && PRETEND=0 |
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|
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#--------------------------------------------------------------------- |
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#- Early exit conditions: |
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|
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if [ -z "$SCANLOG" ] || [ ! -f "$SCANLOG" ]; then |
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logmessage "ERROR: No log file to scan. Nothing to do for me." |
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end 1 |
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fi |
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|
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if [ $SEEKSTART != 1 ] && [ $LOGFOLLOW == 0 ]; then |
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logmessage "ERROR: No seek, no follow. Nothing to do for me." |
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end 1 |
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fi |
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|
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#--------------------------------------------------------------------- |
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|
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# Flag for marking the first run: |
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FirstRun=1 |
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|
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while [ -e $SCANLOG ]; do |
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|
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#LogSize=`du -b $SCANLOG | cut -f1` |
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LogSize=$(stat -c %s $SCANLOG) |
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|
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if [ "$FirstRun" == 1 ]; then |
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if [ "$SEEKSTART" == 1 ]; then |
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logmessage "Reading '$SCANLOG' from start. File size is '$LogSize' bytes." |
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else |
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OldLogSize=$LogSize |
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fi |
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fi |
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|
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if ((LogSize > OldLogSize)); then |
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|
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tail --bytes=$[LogSize - OldLogSize] $SCANLOG | \ |
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while read LogFileLine; do |
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|
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DateTime=`echo "\$LogFileLine" | awk -F' ' '{ print $1 " " $2 " " $3 }'` |
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LogFileMsg=`echo "\$LogFileLine" | awk -F' ' '{ $1=""; $2=""; $3=""; print $0 }'` |
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|
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case "$LogFileLine" in |
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|
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($MatchP1) |
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Username=`echo "\$LogFileMsg" | cut -d' ' -f8` |
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IP=`echo "\$LogFileMsg" | cut -d' ' -f10` |
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logmessage "SSH: illegal login as '$Username' from '$IP' at '$DateTime'." |
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[ "$DROP_SSH_ILLEGALUSER" == 1 ] && dropaddress $IP |
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;; |
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|
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($MatchN2) |
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;; |
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|
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($MatchP2) |
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Username=`echo "\$LogFileMsg" | cut -d' ' -f9` |
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IP=`echo "\$LogFileMsg" | cut -d' ' -f11` |
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logmessage "SSH: failed password for '$Username' from '$IP' at '$DateTime'." |
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dropaddress $IP |
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;; |
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|
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($MatchN3) |
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;; |
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|
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($MatchP3) |
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Username=`echo "\$LogFileMsg" | cut -d' ' -f11` |
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IP=`echo "\$LogFileMsg" | cut -d' ' -f13` |
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logmessage "SSH: incorrect password for '$Username' from '$IP' at '$DateTime'." |
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dropaddress $IP |
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;; |
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|
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($MatchFTP_P1) |
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Address=`echo "\$LogFileMsg" | cut -d' ' -f10` |
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Username=`echo "\$LogFileMsg" | cut -d' ' -f11` |
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Address=${Address/,} |
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IP=$(resolveip -s $Address) |
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logmessage "FTP: failed login as '$Username' from '$IP' at '$DateTime'." |
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[ "$DROP_FTP_FAILEDLOGIN" == 1 ] && dropaddress $IP |
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;; |
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|
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esac |
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done |
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|
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elif ((OldLogSize > LogSize)); then |
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logmessage "'$SCANLOG' has been truncated. New file size is '$LogSize' bytes." |
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fi |
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|
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OldLogSize=$LogSize |
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|
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[ "$LOGFOLLOW" != 1 ] && end |
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|
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[ "$FirstRun" == 1 ] && [ "$LOGFOLLOW" == 1 ] && \ |
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logmessage "Following. Scanning '$SCANLOG' every '$INTERVAL' second(s)." |
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|
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# First run just ended: |
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FirstRun=0 |
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|
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# Make the defined pause: |
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sleep $INTERVAL |
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done |
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|
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#--------------------------------------------------------------------- |
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