生产服务器通常多个用户具有登录权限和操作权限。那么我们怎么需要知道这些用户登录服务器后做了哪些操作？这就需要做命令审计，即统计登录用户在服务器上执行了哪些命令。
下面是命令审计的方法：
1、创建一个配置文件，名为/etc/bash_franzi 文件内容如下：
#!/usr/bin/env bash
#Pointsoftware AG, 2013-11-03
#created by francois scheurer
#filename: ‘/etc/bash_franzi‘
#This file must be sourced by ‘~/.bashrc‘, which is the last runned startup script for bash invocation for login interactive, login non-interactive and non-login interactive shells.
#
#Having a complete history of all typed commands can be very helpful in many scenarios:
# when several administrators work together on the same server and need to know what was done previously
# when someone need to redo an older sequence of commands or to understand an undocumented maintenance process
# for troubleshooting or forensic analysis, by crosschecking the date of an event or of a file with the commands executed at that date
#
#The standard ‘.bash_history‘ file of the shell is unfortunately not written on disk in the case of a crash and it may be deleted by the user.
#Another problem is that when many shell sessions are running concurrently, their logging will only occur when they are closed, therefore the commands of the history will not appear in their chronological order.
#Furthermore, ‘.bash_history‘ will not include essential information like the ‘working directory‘ of the command; and by default the repetition or re-edition of commands will not be logged, too.
#
#Some solutions exist to improve this, either by patching or installing binaries:
# ‘bash-BOFH‘ patching and recompiling: works well but need a new patch for each release of the bash
# ‘snoopy‘: is logging all commands except shell builtins
# ‘rootsh / sniffy / ttyrpld / ttysnoop‘: logs everything, also output of commands, it may be useful but it generates very verbose logs
# ‘grsecurity‘ patched kernels: powerful but it may be a not suitable solution if an official kernel is required (e.g. for Oracle DB)
# there is also an old ‘sshd‘ patch (‘http://www.kdvelectronics.eu/ssh-logging/ssh-logging.html‘)
# ‘screen -x‘ can also be useful for cooperation work, but it is not a command logger
#
#In contrast to that, the presented method is very easy to deploy; it is just a shellscript that is running in bash (standard shell on most systems) and therefore it is architecture independent.
#It will allow a complete audit of all commands/builtins executed interactively in the bash.
#Note that a user can avoid calling this file by starting a shell with options like ‘--norc‘; he also can unset or overwrite variables like ‘PROMPT_COMMAND‘.
#Therefore this script is useful for audit but an alternative solution with bash patching should be considered if the security requirements are the priority.
#
#Note on Solaris:
# In Solaris please use ‘grep‘ without the ‘-q‘ option, like this:
# if groups | grep root &>/dev/null
# Please also remove the following line (chattr unsupported in Solaris:
# chattr +a "$HISTFILE"
# Then modify your /etc/syslog.conf to include this line:
# user.info /var/adm/userlog.info
# To assign ‘bash‘ as the login shell in Solaris: passwd -e /bin/bash .
# Make sure that the audit-script is sourced (=included) correctly during the bash invocation.
# If your bash version is too old, $HISTCONTROL will not allow you to log duplicated commands correctly.
# svcadm restart system/system-log
# svcadm disable ssh
# svcadm enable ssh
if [ "${SHELL##*/}" != "bash" ]; then
return
fi
#to avoid sourcing this file more than once
if [ -n "${OSTYPE##solaris*}" ]; then #following not working in solaris
#do not source this file twice; also do not source it if we are in forcecommand.sh, source it later from "-bash-li"
#if we would source it from forcecommand.sh, the environment would be lost after the call of ‘exec -l bash -li‘
if [ "$AUDIT_INCLUDED" == "$$" ] || { [ -z "$SSH_ORIGINAL_COMMAND" ] && [ "$(cat /proc/$$/cmdline)" == ‘bash-c"/etc/forcecommand.sh"‘ ]; }; then
return
else
declare -rx AUDIT_INCLUDED="$$"
fi
fi
#prompt & color
#‘http://www.pixelbeat.org/docs/terminal_colours/#256‘
#‘http://www.frexx.de/xterm-256-notes/‘
_backnone="\e[00m"
_backblack="\e[40m"
_backblue="\e[44m"
_frontred_b="\e[01;31m"
_frontgreen_b="\e[01;32m"
_frontgrey_b="\e[01;37m"
_frontgrey="\e[00;37m"
_frontblue_b="\e[01;34m"
#PS1="\[${_backblue}${_frontgrey_b}\]\[email protected]\h:\[${_backblack}${_frontblue_b}\]\w\\$\[${_backnone}${_frontgrey_b}\] " #grey
PS1="\[${_backblue}${_frontgreen_b}\]\[email protected]\h:\[${_backblack}${_frontblue_b}\]\w\\$\[${_backnone}${_frontgreen_b}\] " #green
#PS1="\[${_backblue}${_frontred_b}\]\[email protected]\h:\[${_backblack}${_frontblue_b}\]\w\\$\[${_backnone}${_frontred_b}\] " #red
declare -rx PS1
#‘history‘ options
declare -rx HISTFILE="$HOME/.bash_history"
declare -rx HISTSIZE=500000 #nbr of cmds in memory
declare -rx HISTFILESIZE=500000 #nbr of cmds on file
declare -rx HISTCONTROL="" #does not ignore spaces or duplicates
declare -rx HISTIGNORE="" #does not ignore patterns
declare -rx HISTCMD #history line number
#following line is commented to avoid following issue: loading the history during the sourcing of this file (non-interactive bash) is also loading history lines that begin with ‘#‘, but then during the trap DEBUG calls it reloads the whole history without ‘#‘-lines and produces an double-length history.
#history -r #to reload history from file if a prior HISTSIZE has truncated it
#following 2 lines commented because ‘history -r‘ was still loading ‘#‘-lines
#shopt -s extglob #enable extended pattern matching operators
#HISTIGNORE="*([ \t])#*"; history -r #reload history without commented lines; this force non-interactive bash to behave like interactive bash, without this AUDIT_HISTLINE will get a wrong initial value, leading then to a small issue where empty bash sessions are actually logging the last command of history
if [ -n "${OSTYPE##solaris*}" ]; then #following not working in solaris
if groups | grep -q root; then
declare -x TMOUT=43200 #timeout for root‘s sessions
chattr +a "$HISTFILE" #set append-only
fi
fi
shopt -s histappend
shopt -s cmdhist
#history substitution ask for a confirmation
shopt -s histverify
#add timestamps in history - obsoleted with logger/syslog
#‘http://www.thegeekstuff.com/2008/08/15-examples-to-master-linux-command-line-history/#more-130‘
#declare -rx HISTTIMEFORMAT=‘%F %T ‘
#enable forward search (‘ctrl-s‘)
#‘http://ruslanspivak.com/2010/11/25/bash-history-incremental-search-forward/‘
if shopt -q login_shell && [ -t 0 ]; then
stty -ixon
fi
#bash audit & traceability
#
#
#
declare -rx AUDIT_LOGINUSER="$(who -mu | awk ‘{print $1}‘)"
declare -rx AUDIT_LOGINPID="$(who -mu | awk ‘{print $6}‘)"
declare -rx AUDIT_USER="$USER" #defined by pam during su/sudo
declare -rx AUDIT_PID="$$"
declare -rx AUDIT_TTY="$(who -mu | awk ‘{print $2}‘)"
declare -rx AUDIT_SSH="$([ -n "$SSH_CONNECTION" ] && echo "$SSH_CONNECTION" | awk ‘{print $1":"$2"->"$3":"$4}‘)"
declare -rx AUDIT_STR="[audit $AUDIT_LOGINUSER/$AUDIT_LOGINPID as $AUDIT_USER/$AUDIT_PID on $AUDIT_TTY/$AUDIT_SSH]"
declare -x AUDIT_LASTHISTLINE="" #to avoid logging the same line twice
declare -rx AUDIT_SYSLOG="1" #to use a local syslogd
#
#
#
#the logging at each execution of command is performed with a trap DEBUG function
#and having set the required history options (HISTCONTROL, HISTIGNORE)
#and to disable the trap in functions, command substitutions or subshells.
#it turns out that this solution is simple and works well with piped commands, subshells, aborted commands with ‘ctrl-c‘, etc..
set +o functrace #disable trap DEBUG inherited in functions, command substitutions or subshells, normally the default setting already
shopt -s extglob #enable extended pattern matching operators
function AUDIT_DEBUG() {
if [ -z "$AUDIT_LASTHISTLINE" ]; then #initialization
local AUDIT_CMD="$(fc -l -1 -1)" #previous history command
AUDIT_LASTHISTLINE="${AUDIT_CMD%%+([^ 0-9])*}"
else
AUDIT_LASTHISTLINE="$AUDIT_HISTLINE"
fi
local AUDIT_CMD="$(history 1)" #current history command
AUDIT_HISTLINE="${AUDIT_CMD%%+([^ 0-9])*}"
if [ "${AUDIT_HISTLINE:-0}" -ne "${AUDIT_LASTHISTLINE:-0}" ] || [ "${AUDIT_HISTLINE:-0}" -eq "1" ]; then #avoid logging unexecuted commands after ‘ctrl-c‘, ‘empty+enter‘, or after ‘ctrl-d‘
echo -ne "${_backnone}${_frontgrey}" #disable prompt colors for the command‘s output
#remove in last history cmd its line number (if any) and send to syslog
if [ -n "$AUDIT_SYSLOG" ]; then
if ! logger -p user.info -t "$AUDIT_STR $PWD" "${AUDIT_CMD##*( )?(+([0-9])?(\*)+( ))}"; then
echo error "$AUDIT_STR $PWD" "${AUDIT_CMD##*( )?(+([0-9])?(\*)+( ))}"
fi
else
echo $( date +%F_%H:%M:%S ) "$AUDIT_STR $PWD" "${AUDIT_CMD##*( )?(+([0-9])?(\*)+( ))}" >>/var/log/userlog.info
fi
#echo "===cmd:$BASH_COMMAND/subshell:$BASH_SUBSHELL/fc:$(fc -l -1)/history:$(history 1)/histline:${AUDIT_CMD%%+([^ 0-9])*}/last_histline:${AUDIT_LASTHISTLINE}===" #for debugging
return 0
else
return 1
fi
}
#
#
#
#audit the session closing
function AUDIT_EXIT() {
local AUDIT_STATUS="$?"
if [ -n "$AUDIT_SYSLOG" ]; then
logger -p user.info -t "$AUDIT_STR" "#=== session closed ==="
else
echo $( date +%F_%H:%M:%S ) "$AUDIT_STR" "#=== session closed ===" >>/var/log/userlog.info
fi
exit "$AUDIT_STATUS"
}
#
#
#
#make audit trap functions readonly; disable trap DEBUG inherited (normally the default setting already)
declare -frx +t AUDIT_DEBUG
declare -frx +t AUDIT_EXIT
#
#
#
#audit the session opening
if [ -n "$AUDIT_SYSLOG" ]; then
logger -p user.info -t "$AUDIT_STR" "#=== session opened ===" #audit the session openning
else
echo $( date +%F_%H:%M:%S ) "$AUDIT_STR" "#=== session opened ===" >>/var/log/userlog.info
fi
#
#
#
#when a bash command is executed it launches first the AUDIT_DEBUG(),
#then the trap DEBUG is disabled to avoid a useless rerun of AUDIT_DEBUG() during the execution of pipes-commands;
#at the end, when the prompt is displayed, re-enable the trap DEBUG
#declare -rx PROMPT_COMMAND="AUDIT_DONE=; trap ‘AUDIT_DEBUG && AUDIT_DONE=1; trap DEBUG‘ DEBUG; [ -n \"\$AUDIT_DONE\" ] && echo ‘-----------------------------‘"
#NOK: declare -rx PROMPT_COMMAND="echo "-----------------------------"; trap ‘AUDIT_DEBUG; trap DEBUG‘ DEBUG; echo ‘-----------------------------‘"
#OK: declare -rx PROMPT_COMMAND="echo "-----------------------------"; trap ‘AUDIT_DEBUG; trap DEBUG‘ DEBUG"
declare -rx PROMPT_COMMAND="[ -n \"\$AUDIT_DONE\" ] && echo ‘-----------------------------‘; AUDIT_DONE=; trap ‘AUDIT_DEBUG && AUDIT_DONE=1; trap DEBUG‘ DEBUG"
declare -rx BASH_COMMAND #current command executed by user or a trap
declare -rx SHELLOPT #shell options, like functrace
trap AUDIT_EXIT EXIT #audit the session closing
#endof
2、修改配置文件的属主数组和权限
#chown root:root /etc/bash_franzi #chmod 644 /etc/bash_franzi
3、在命令行运行以下命令，让文件在系统启动时自动加载
for i in /etc/profile /etc/skel/.bashrc /root/.bashrc /home/*/.bashrc; do if ! grep -q ". /etc/bash_franzi" "$i"; then echo "===updating $i===" echo "[ -f /etc/bash_franzi ] && . /etc/bash_franzi #added by francois scheurer" >>"$i" fi done
4、运行以下命令，配置/etc/rsyslog.conf文件
cat >>/etc/rsyslog.conf <<"EOF" #added by francois scheurer $ActionFileDefaultTemplate RSYSLOG_FileFormat #stop avahi if messages are dropped (cf. /var/log/messages with ‘net_ratelimit‘ or ‘imuxsock begins to drop‘) #update-rc.d -f avahi-daemon remove && service avahi-daemon stop #https://isc.sans.edu/diary/Are+you+losing+system+logging+information+%28and+don%27t+know+it%29%3F/15106 #$SystemLogRateLimitInterval 10 #$SystemLogRateLimitBurst 500 $SystemLogRateLimitInterval 0 #endof EOF
5、创建‘/etc/rsyslog.d/45-franzi.conf’配置文件
cat >/etc/rsyslog.d/45-franzi.conf <<"EOF" #added by francois scheurer # Filter duplicated messages $RepeatedMsgReduction off # Enable high precision timestamps $ActionFileDefaultTemplate RSYSLOG_FileFormat # Log bash audit generated log messages to file if $syslogfacility-text == ‘user‘ and $syslogseverity-text == ‘info‘ and $syslogtag startswith ‘[audit‘ then /var/log/userlog.info #then drop them & ~ #‘http://content.hccfl.edu/pollock/aunix2/logging.htm‘ #‘http://www.rsyslog.com/doc/rsyslog_conf_filter.html‘ EOF
6、重启rsyslog服务
/etc/init.d/rsyslog restart
效果：命令审计的日志保存在/var/log/userlog.info文件中
[email protected]:~# tail /var/log/userlog.info 2016-08-26T11:02:37.909499+08:00 localhost [audit root/23038 as root/23038 on pts/3/172.16.100.57:51374->10.10.10.202:22] /opt/sonar/conf: service iptables status 2016-08-26T11:02:44.619996+08:00 localhost [audit root/23038 as root/23038 on pts/3/172.16.100.57:51374->10.10.10.202:22] /opt/sonar/conf: service iptables stop 2016-08-26T11:02:50.489505+08:00 localhost [audit root/23038 as root/23038 on pts/3/172.16.100.57:51374->10.10.10.202:22] /opt/sonar/conf: sestatus -v 2016-08-26T11:03:03.369423+08:00 localhost [audit root/23038 as root/23038 on pts/3/172.16.100.57:51374->10.10.10.202:22] /opt/sonar/conf: chkconfig --list iptables 2016-08-26T11:03:27.191368+08:00 localhost [audit root/23038 as root/23038 on pts/3/172.16.100.57:51374->10.10.10.202:22] /opt/sonar/conf: service ip6tables stop 2016-08-26T11:03:41.546837+08:00 localhost [audit root/23038 as root/23038 on pts/3/172.16.100.57:51374->10.10.10.202:22] /opt/sonar/conf: chkconfig ip6tables off 2016-08-26T11:13:40.509537+08:00 localhost [audit root/23038 as root/23038 on pts/3/172.16.100.57:51374->10.10.10.202:22] /opt/sonar/conf: /etc/init.d/jenkins stop 2016-08-26T11:13:46.641555+08:00 localhost [audit root/23038 as root/23038 on pts/3/172.16.100.57:51374->10.10.10.202:22] /opt/sonar/conf: /etc/init.d/jenkins start 2016-08-26T11:13:56.839747+08:00 localhost [audit root/23038 as root/23038 on pts/3/172.16.100.57:51374->10.10.10.202:22] /opt/sonar/conf: ps -ef | grep jenkins 2016-08-26T11:28:36.159554+08:00 localhost [audit root/19576 as root/19576 on pts/2/172.16.100.216:57196->10.10.10.202:22] /root: tail /var/log/userlog.info
时间： 2024-10-10 00:38:48