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关于企业IT系统建设安全性问题在任何时候都不会成为一个过时的话题，企业在构建适合自己业务需求的IT系统之初以及整个IT系统生命周期内，系统的安全运行都是一项非常重要的工作，而作为系统运维人员更有责任为保证系统的安全、稳定的运行身体力行。 So本博文提供了关于Linux系统安全加固的具体实现脚本及基线检查规范，以供主机维护人员参考学习。 其中以下脚本主要实现的功能包括： *加固项包括：密码长度、session超时时间、删除不用的帐号和组、限制root用户直接telnet或rlogin、ssh *检查是否存在除root之外UID为0的用户、确保root用户的系统路径中不包含父目录，在非必要的情况下，不应包含组权限为777的目录 *检查操作系统Linux用户umask设置、检查重要目录和文件的权限、禁止除root之外的用户su操作、查找系统中任何人都有写权限的目录 *查找系统中没有属主的文件、查找系统中的隐藏文件、判断日志与审计是否合规、登录超时设置、禁用不必要的服务 *linux 安全加固适用于redhat、centos5.8至6.2 具体内容如下，请结合自身业务需求进行系统级加固： #1、--------------------------------------------------------------------- echo "删除不用的帐号和组" echo "delete unused users and grups" for i in lp sync shutdown halt news uucp operator games gopher do echo "will delete user $i" userdel $i echo "user $i have delete" done for i in lp sync shutdown halt news uucp operator games gopher do echo "will delete group $i" groupdel $i echo "group $i have delete" done date=`date +%F` #2、----------------------------------------------- #section1 密码要求密码长度大于8,口令90天过期/etc/login.defs #----------------------------------------------- #--------------------------------------------------------------------- echo "cp /etc/login.defs to /etc/login.defs.bak_%date" echo "#-------------------------------------" cp /etc/login.defs /etc/login.defs.bak_$date #echo "检查密码的配置" echo "Check the configure for user's password." echo "#-------------------------------------" for i in PASS_MAX_DAYS PASS_MIN_LEN PASS_MIN_DAYS PASS_WARN_AGE do cat /etc/login.defs |grep $i|grep -v \# done #set password min length 8 echo "#-------------------------------------" echo "Set user's password min length is 8" sed -i '/PASS_MIN_LEN/s/5/8/g' /etc/login.defs echo "#-------------------------------------" #set password max day 90 #echo "set password expired 90 day" #sed -i '/PASS_MAX_DAYS/s/99999/90/g' /etc/login.defs #3、--------------------------------------------------------------------- echo "#检查是否存在空口令" echo "Check if there have user without password!" echo "#-------------------------------------" awk -F: '($2 == "") { print $1 }' /etc/shadow #4、----------------------------------------------- #section2 限制root用户直接telnet或rlogin，ssh无效 ######建议在/etc/securetty文件中配置：CONSOLE = /dev/tty01 #--------------------------------------------------------------------- #帐号与口令-检查是否存在除root之外UID为0的用户 #echo "#检查系统中是否存在其它id为0的用户" echo "Check if the system have other user's id is 0" echo "#-------------------------------------" mesg=`awk -F: '($3 == 0) { print $1 }' /etc/passwd|grep -v root` if [ -z $mesg ] then echo "There don't have other user uid=0" else echo echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" echo "$mesg uid=0" echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" fi #5、--------------------------------------------------------------------- echo "#确保root用户的系统路径中不包含父目录，在非必要的情况下，不应包含组权限为777的目录" echo "check the Path set for root,make sure the path for root dont have father directory and 777 rights" echo "#-------------------------------------" echo $PATH | egrep '(^|:)(\.|:|$)' find `echo $PATH | tr ':' ' '` -type d \( -perm -002 -o -perm -020 \) -ls #6、--------------------------------------------------------------------- echo "#检查操作系统Linux远程连接" echo "Check if system have remote connection seting" echo "#-------------------------------------" find / -name .netrc find / -name .rhosts echo "检查操作系统Linux用户umask设置" echo "Check the system users umask setting" echo "#-------------------------------------" for i in /etc/profile /etc/csh.login /etc/csh.cshrc /etc/bashrc do grep -H umask $i|grep -v "#" done ###################设置umask为027 #7、--------------------------------------------------------------------- #echo "#检查重要目录和文件的权限" ##echo "Check the important files and directory rights" echo "#-------------------------------------" for i in /etc /etc/rc.d/init.d /tmp /etc/inetd.conf /etc/passwd /etc/shadow /etc/group /etc/security /etc/services /etc/rc*.d do ls -ld $i done echo -n "Please check if the output is ok ? yes or no :" read i case $i in y|yes) break ;; n|no) echo "Please recheck the output!" echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" continue ;; *) echo "please input yes or no" ;; esac #8、--------------------------------------------------------------------- #echo "#配置rc.d下脚本的权限" echo "Configure the scripts right(750) in rc.d directory" echo "#-------------------------------------" chmod -R 750 /etc/rc.d/init.d/* chmod 755 /bin/su 改了之后只能root su，没有了s位别的用户无法成功su chmod 664 /var/log/wtmp #chattr +a /var/log/messages #9、--------------------------------------------------------------------- echo "#查找系统中存在的SUID和SGID程序" echo "Find the files have suid or Sgid" echo "#-------------------------------------" for PART in `grep -v ^# /etc/fstab | awk '($6 != "0") {print $2 }'`; do find $PART \( -perm -04000 -o -perm -02000 \) -type f -xdev -print |xargs ls -ld done echo -n "Please check if the output is ok ? yes or no :" read i case $i in y|yes) break ;; n|no) echo "Please recheck the output!" echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" continue ;; *) echo "please input yes or no" ;; esac #10、--------------------------------------------------------------------- echo "#查找系统中任何人都有写权限的目录" echo "Find the directory everyone have the write right" echo "#-------------------------------------" for PART in `awk '($3 == "ext2" || $3 == "ext3") \ { print $2 }' /etc/fstab`; do find $PART -xdev -type d \( -perm -0002 -a ! -perm -1000 \) -print |xargs ls -ld done echo -n "Please check if the output is ok ? yes or no :" read i case $i in y|yes) break ;; n|no) echo "Please recheck the output!" echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" continue ;; *) echo "please input yes or no" ;; esac #11、--------------------------------------------------------------------- #echo "#查找系统中任何人都有写权限的文件" echo "Find the files everyone have write right" echo "#-------------------------------------" for PART in `grep -v ^# /etc/fstab | awk '($6 != "0") {print $2 }'`; do find $PART -xdev -type f \( -perm -0002 -a ! -perm -1000 \) -print |xargs ls -ld done echo -n "Please check if the output is ok ? yes or no :" read i case $i in y|yes) break ;; n|no) echo "Please recheck the output!" echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" continue ;; *) echo "please input yes or no" ;; esac #12、--------------------------------------------------------------------- echo "#查找系统中没有属主的文件" echo "Find no owner or no group files in system" echo "#-------------------------------------" for PART in `grep -v ^# /etc/fstab |grep -v swap| awk '($6 != "0") {print $2 }'`; do find $PART -nouser -o -nogroup |grep -v "vmware"|grep -v "dev"|xargs ls -ld done echo -n "Please check if the output is ok ? yes or no :" read i case $i in y|yes) break ;; n|no) echo "Please recheck the output!" echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" continue ;; *) echo "please input yes or no" ;; esac #13、--------------------------------------------------------------------- ###echo "#查找系统中的隐藏文件" ##echo " Find the hiding file in system" ##echo "#-------------------------------------" ###linux执行报错\排除/dev”目录下的那些文件 ####find / -name \(".. *" -o "…*" -o ".xx" -o ".mail" \) -print -xdev ## #find / -name "…*" -print -xdev | cat -v ##find / \( -name ".*" -o -name "…*" -o -name ".xx" -o -name ".mail" \) -xdev ##echo -n "If you have check all the output files if correct yes or no ? :" ##read i ## case $i in ## y|yes) ## break ## ;; ## n|no) ## echo "Please recheck the output!" ## echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" ## continue ## ;; ## *) ## echo "please input yes or no" ## ;; ## esac ## #14、--------------------------------------------------------------------- echo "#判断日志与审计是否合规" echo "Judge if the syslog audition if follow the rules" echo "#-------------------------------------" autmesg=`cat /etc/syslog.conf |egrep ^authpriv` if [ ! -n "$autmesg" ] then echo "there don't have authpriv set in /etc/syslog.conf" echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" echo -n "If you have know this y or n ?" read i case $i in y|yes) break ;; n|no) echo "there don't have authpriv set in /etc/syslog.conf" echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" continue ;; *) echo "please input yes or no" ;; esac else # echo "日志与审计合规" echo "syslog audition follow the rules" fi #15、--------------------------------------------------------------------- echo "#关闭linux core dump" echo "Turn off the system core dump" echo "#-------------------------------------" mesg1=`grep "* soft core 0" /etc/security/limits.conf` mesg2=`grep "* hard core 0" /etc/security/limits.conf` if [ ! -n "$mesg1" -o ! -n "$mesg2" ] then cp /etc/security/limits.conf /etc/security/limits.conf_$date if [ ! -n "$mesg1" ] then echo "* soft core 0" >> /etc/security/limits.conf fi if [ ! -n "$mesg2" ] then echo "* hard core 0" >> /etc/security/limits.conf fi fi #修改login文件使limits限制生效 cp /etc/pam.d/login /etc/pam.d/login_$date echo "session required /lib/security/pam_limits.so" >> /etc/pam.d/login #16、--------------------------------------------------------------------- #登录超时设置 #检查/etc/pam.d/system-auth文件是否存在account required /lib/security/pam_tally.so deny=的相关设置 #建议设置为auth required pam_tally.so onerr=fail deny=6 unlock_time=300 #17、--------------------------------------------------------------------- #su命令使用,对su命令使用进行限制设置 #检查/etc/pam.d/su文件设置 #文件中包含 #auth sufficient /lib/security/pam_rootok.so debug #auth required /lib/security/pam_wheel.so group=isd #20、--------------------------------------------------------------------- echo "#登录超时自动退出" echo "set session time out terminal " echo "#-------------------------------------" tmout=`grep -i TMOUT /etc/profile` if [ ! -n "$tmout" ] then echo echo -n "do you want to set login timeout to 300s? [yes]:" read i case $i in y|yes) cp /etc/profile /etc/profile_$date echo "export TMOUT=300" >> /etc/profile . /etc/profile ;; n|no) break ;; *) echo "please input yes or no" ;; esac else mesg=`echo $tmout |awk -F"=" '{print $2}'` if [ "$mesg" -ne 300 ] then echo "The login session timeout is $mesg now will change to 300 seconds" cp /etc/profile /etc/profile_$date echo "export TMOUT=300" >> /etc/profile . /etc/profile fi fi sed -i 's/HISTSIZE=1000/HISTSIZE=100/g' /etc/profile #21、--------------------------------------------------------------------- echo "#禁用telnet启用ssh" echo "Stop telnet and start up sshd" echo "#-------------------------------------" mesg1=`lsof -i:23` mesg2=`lsof -i:22` if [ ! -n "$mesg2" ] then service start sshd chkconfig sshd on mesg2=`lsof -i:22` fi if [ ! -n "$mesg1" -a ! -n "$mesg2" ] then echo echo "Will Deactive telnet" chkconfig krb5-telnet off chkconfig ekrb5-telnet off fi #22、--------------------------------------------------------------------- #echo "#设置终端超时，使系统10分钟后自动退出不活动的Shell" #echo "#-------------------------------------" #mesg=`grep "export TMOUT=600" /etc/profile` #if [ -z $mesg ] #then #echo "export TMOUT=600" >>/etc/profile #. /etc/profile #fi #23、--------------------------------------------------------------------- echo "#禁用不必要的服务" echo "Stop unuseing services" echo "#-------------------------------------" list="avahi-daemon bluetooth cups firstboot hplip ip6tables iptables iscsi iscsid isdn kudzu pcscd rhnsd rhsmcertd rpcgssd rpcidmapd sendmail smartd yum-updatesd netfs portmap autofs nfslock nfs" for i in $list do chkconfig $i off service $i stop done echo "change kernel parameter for network secure" cp /etc/sysctl.conf /etc/sysctl.conf.$date #echo "net.ipv4.icmp_echo_ignore_all = 1">>/etc/sysctl.conf sysctl -a |grep arp_filter|sed -e 's/\=\ 0/\=\ 1/g' >>/etc/sysctl.conf sysctl -a |grep accept_redirects|sed -e 's/\=\ 1/\=\ 0/g' >>/etc/sysctl.conf sysctl -a |grep send_redirects|sed -e 's/\=\ 1/\=\ 0/g' >>/etc/sysctl.conf sysctl -a |grep log_martians |sed -e 's/\=\ 0/\=\ 1/g'>>/etc/sysctl.conf sysctl -p #24、--------------------------------------------------------------------- echo "设置热键" #ctrl+alt+del if [ -d /etc/init ] then sed -i 's/^[^#]/#&/g' /etc/control-alt-delete.conf else sed -i 's/^ca::/#&/g' /etc/inittab fi #25、--------------------------------------------------------------------- echo "demo:禁止除了db2inst1的用户su到root" usermod -G wheel db2inst1 sed -i '/pam_wheel.so use_uid/s/^#//g' /etc/pam.d/su echo "SU_WHEEL_ONLY yes">>/etc/login.defs (责任编辑：IT) |