#!/bin/sh - # # $NetBSD: security,v 1.56 2001/06/18 10:54:02 lukem Exp $ # from: @(#)security 8.1 (Berkeley) 6/9/93 # PATH=/sbin:/usr/sbin:/bin:/usr/bin if [ -f /etc/rc.subr ]; then . /etc/rc.subr else echo "Can't read /etc/rc.subr; aborting." exit 1; fi umask 077 if [ -s /etc/security.conf ]; then . /etc/security.conf fi SECUREDIR=`mktemp -d /tmp/_securedir.XXXXXX` || exit 1 trap "/bin/rm -rf $SECUREDIR ; exit 0" EXIT INT QUIT if ! cd "$SECUREDIR"; then echo "Can not cd to $SECUREDIR". exit 1 fi if [ -z "$max_loginlen" ];then max_loginlen=8 fi if [ -z "$max_grouplen" ]; then max_grouplen=8 fi ERR=secure1.$$ TMP1=secure2.$$ TMP2=secure3.$$ MPBYUID=secure4.$$ MPBYPATH=secure5.$$ LIST=secure6.$$ OUTPUT=secure7.$$ LABELS=secure8.$$ # Handle backup_dir not being set in .conf file backup_dir=${backup_dir:-/var/backups} MP=/etc/master.passwd # these is used several times. awk -F: '!/^+/ { print $1 " " $3 }' $MP | sort -k2n > $MPBYUID awk -F: '{ print $1 " " $9 }' $MP | sort -k2 > $MPBYPATH # Check the master password file syntax. # if checkyesno check_passwd; then awk -v "len=$max_loginlen" ' BEGIN { while ( getline < "/etc/shells" > 0 ) { if ($0 ~ /^\#/ || $0 ~ /^$/ ) continue; shells[$1]++; } FS=":"; } { if ($0 ~ /^[ ]*$/) { printf "Line %d is a blank line.\n", NR; next; } if (NF != 10 && ($1 != "+" || NF != 1)) printf "Line %d has the wrong number of fields.\n", NR; if ($1 == "+" ) { if (NF != 1 && $3 == 0) printf "Line %d includes entries with uid 0.\n", NR; next; } if ($1 !~ /^[A-Za-z0-9]([-A-Za-z0-9]*[A-Za-z0-9])*$/) printf "Login %s has non-alphanumeric characters.\n", $1; if (length($1) > len) printf "Login %s has more than "len" characters.\n", $1; if ($2 == "") printf "Login %s has no password.\n", $1; if (length($2) != 13 && length($2) != 20 && length($2) != 34 && $2 != "") { if ($10 == "" || shells[$10]) printf "Login %s is off but still has a valid shell (%s)\n", $1, $10; } else if (! shells[$10]) printf "Login %s does not have a valid shell (%s)\n", $1, $10; if ($3 == 0 && $1 != "root" && $1 != "toor") printf "Login %s has a user id of 0.\n", $1; if ($3 < 0) printf "Login %s has a negative user id.\n", $1; if ($4 < 0) printf "Login %s has a negative group id.\n", $1; }' < $MP > $OUTPUT if [ -s $OUTPUT ] ; then printf "\nChecking the $MP file:\n" cat $OUTPUT fi awk -F: '{ print $1 }' $MP | sort | uniq -d > $OUTPUT if [ -s $OUTPUT ] ; then printf "\n$MP has duplicate user names.\n" column $OUTPUT fi # To not exclude 'toor', a standard duplicate root account, from the duplicate # account test, uncomment the line below (without egrep in it)and comment # out the line (with egrep in it) below it. # # < $MPBYUID uniq -d -f 1 | awk '{ print $2 }' > $TMP2 < $MPBYUID egrep -v '^toor ' | uniq -d -f 1 | awk '{ print $2 }' > $TMP2 if [ -s $TMP2 ] ; then printf "\n$MP has duplicate user id's.\n" while read uid; do grep -w $uid $MPBYUID done < $TMP2 | column fi fi # Backup the master password file; a special case, the normal backup # mechanisms also print out file differences and we don't want to do # that because this file has encrypted passwords in it. # CUR=$backup_dir/${MP##*/}.current BACK=$backup_dir/${MP##*/}.backup if [ -s $CUR ] ; then if cmp -s $CUR $MP; then : else backup_file update $MP $CUR $BACK fi else backup_file add $MP $CUR $BACK fi # Check the group file syntax. # if checkyesno check_group; then GRP=/etc/group awk -F: -v "len=$max_grouplen" '{ if ($0 ~ /^[ ]*$/) { printf "Line %d is a blank line.\n", NR; next; } if (NF != 4 && ($1 != "+" || NF != 1)) printf "Line %d has the wrong number of fields.\n", NR; if ($1 == "+" ) { next; } if ($1 !~ /^[A-Za-z0-9]([-A-Za-z0-9]*[A-Za-z0-9])*$/) printf "Group %s has non-alphanumeric characters.\n", $1; if (length($1) > len) printf "Group %s has more than "len" characters.\n", $1; if ($3 !~ /[0-9]*/) printf "Login %s has a negative group id.\n", $1; }' < $GRP > $OUTPUT if [ -s $OUTPUT ] ; then printf "\nChecking the $GRP file:\n" cat $OUTPUT fi awk -F: '{ print $1 }' $GRP | sort | uniq -d > $OUTPUT if [ -s $OUTPUT ] ; then printf "\n$GRP has duplicate group names.\n" column $OUTPUT fi fi # Check for root paths, umask values in startup files. # The check for the root paths is problematical -- it's likely to fail # in other environments. Once the shells have been modified to warn # of '.' in the path, the path tests should go away. # if checkyesno check_rootdotfiles; then > $OUTPUT rhome=`csh -fc "echo ~root"` umaskset=no list="/etc/csh.cshrc /etc/csh.login ${rhome}/.cshrc ${rhome}/.login" for i in $list ; do if [ -f $i ] ; then if egrep '^[ \t]*umask[ \t]+[0-7]+' $i > /dev/null ; then umaskset=yes fi # double check the umask value itself; ensure that both the # 020 and 002 bits are set. # we handle this in decimal initially to extract the digits, # and then extract the `2' bit of each digit. # this is made especially painful because # bitwise operations were left out of awk. egrep '^[ \t]*umask[ \t]+[0-7]+' $i | awk '{ g= ($2 % 100) - ($2 % 10); g /= 10; g = g % 4; g -= g % 2; if (g != 2) { print "\tRoot umask is group writeable" } o = ($2 % 10); o = o % 4; o -= o % 2; if (o != 2) { print "\tRoot umask is other writeable" } }' | sort -u >> $OUTPUT SAVE_PATH=$PATH unset PATH /bin/csh -f -s << end-of-csh > /dev/null 2>&1 source $i /bin/ls -ldgT \$path > $TMP1 end-of-csh PATH=$SAVE_PATH awk '{ if ($10 ~ /^\.$/) { print "\tThe root path includes ."; next; } } $1 ~ /^d....w/ \ { print "\tRoot path directory " $10 " is group writeable." } \ $1 ~ /^d.......w/ \ { print "\tRoot path directory " $10 " is other writeable." }' \ < $TMP1 >> $OUTPUT fi done if [ $umaskset = "no" -o -s $OUTPUT ] ; then printf "\nChecking root csh paths, umask values:\n$list\n\n" if [ -s $OUTPUT ]; then cat $OUTPUT fi if [ $umaskset = "no" ] ; then printf "\tRoot csh startup files do not set the umask.\n" fi fi > $OUTPUT rhome=/root umaskset=no list="/etc/profile ${rhome}/.profile" for i in $list; do if [ -f $i ] ; then if egrep umask $i > /dev/null ; then umaskset=yes fi egrep umask $i | awk '$2 % 100 < 20 \ { print "\tRoot umask is group writeable" } \ $2 % 10 < 2 \ { print "\tRoot umask is other writeable" }' \ >> $OUTPUT SAVE_PATH=$PATH unset PATH /bin/sh << end-of-sh > /dev/null 2>&1 . $i list=\`echo \$PATH | /usr/bin/sed -e \ 's/^:/.:/;s/:$/:./;s/::/:.:/g;s/:/ /g'\` /bin/ls -ldgT \$list > $TMP1 end-of-sh PATH=$SAVE_PATH awk '{ if ($10 ~ /^\.$/) { print "\tThe root path includes ."; next; } } $1 ~ /^d....w/ \ { print "\tRoot path directory " $10 " is group writeable." } \ $1 ~ /^d.......w/ \ { print "\tRoot path directory " $10 " is other writeable." }' \ < $TMP1 >> $OUTPUT fi done if [ $umaskset = "no" -o -s $OUTPUT ] ; then printf "\nChecking root sh paths, umask values:\n$list\n" if [ -s $OUTPUT ]; then cat $OUTPUT fi if [ $umaskset = "no" ] ; then printf "\tRoot sh startup files do not set the umask.\n" fi fi fi # Root and uucp should both be in /etc/ftpusers. # if checkyesno check_ftpusers; then > $OUTPUT list="uucp "`awk '$2 == 0 { print $1 }' $MPBYUID` for i in $list; do if /usr/libexec/ftpd -C $i ; then printf "\t$i is not denied\n" >> $OUTPUT fi done if [ -s $OUTPUT ]; then printf "\nChecking the /etc/ftpusers configuration:\n" cat $OUTPUT fi fi # Uudecode should not be in the /etc/mail/aliases file. # if checkyesno check_aliases; then for f in /etc/mail/aliases /etc/aliases; do if [ -f $f ] && egrep '^[^#]*(uudecode|decode).*\|' $f; then printf "\nEntry for uudecode in $f file.\n" fi done fi # Files that should not have + signs. # if checkyesno check_rhosts; then list="/etc/hosts.equiv /etc/hosts.lpd" for f in $list ; do if [ -f $f ] && egrep '\+' $f > /dev/null ; then printf "\nPlus sign in $f file.\n" fi done # Check for special users with .rhosts files. Only root and toor should # have .rhosts files. Also, .rhosts files should not have plus signs. awk -F: '$1 != "root" && $1 != "toor" && \ ($3 < 100 || $1 == "ftp" || $1 == "uucp") \ { print $1 " " $9 }' $MP | sort -k2 | while read uid homedir; do if [ -f ${homedir}/.rhosts ] ; then rhost=`ls -ldgT ${homedir}/.rhosts` printf -- "$uid: $rhost\n" fi done > $OUTPUT if [ -s $OUTPUT ] ; then printf "\nChecking for special users with .rhosts files.\n" cat $OUTPUT fi while read uid homedir; do if [ -f ${homedir}/.rhosts -a -r ${homedir}/.rhosts ] && \ cat -f ${homedir}/.rhosts | egrep '\+' > /dev/null ; then printf -- "$uid: + in .rhosts file.\n" fi done < $MPBYPATH > $OUTPUT if [ -s $OUTPUT ] ; then printf "\nChecking .rhosts files syntax.\n" cat $OUTPUT fi fi # Check home directories. Directories should not be owned by someone else # or writeable. # if checkyesno check_homes; then while read uid homedir; do if [ -d ${homedir}/ ] ; then file=`ls -ldgT ${homedir}` printf -- "$uid $file\n" fi done < $MPBYPATH | awk '$1 != $4 && $4 != "root" \ { print "user " $1 " home directory is owned by " $4 } $2 ~ /^-....w/ \ { print "user " $1 " home directory is group writeable" } $2 ~ /^-.......w/ \ { print "user " $1 " home directory is other writeable" }' \ > $OUTPUT if [ -s $OUTPUT ] ; then printf "\nChecking home directories.\n" cat $OUTPUT fi # Files that should not be owned by someone else or readable. list=".Xauthority .netrc" while read uid homedir; do for f in $list ; do file=${homedir}/${f} if [ -f $file ] ; then printf -- "$uid $f `ls -ldgT $file`\n" fi done done < $MPBYPATH | awk '$1 != $5 && $5 != "root" \ { print "user " $1 " " $2 " file is owned by " $5 } $3 ~ /^-...r/ \ { print "user " $1 " " $2 " file is group readable" } $3 ~ /^-......r/ \ { print "user " $1 " " $2 " file is other readable" } $3 ~ /^-....w/ \ { print "user " $1 " " $2 " file is group writeable" } $3 ~ /^-.......w/ \ { print "user " $1 " " $2 " file is other writeable" }' \ > $OUTPUT # Files that should not be owned by someone else or writeable. list=".bash_history .bash_login .bash_logout .bash_profile .bashrc \ .cshrc .emacs .exrc .forward .history .klogin .login .logout \ .profile .qmail .rc_history .rhosts .tcshrc .twmrc .xinitrc \ .xsession" while read uid homedir; do for f in $list ; do file=${homedir}/${f} if [ -f $file ] ; then printf -- "$uid $f `ls -ldgT $file`\n" fi done done < $MPBYPATH | awk '$1 != $5 && $5 != "root" \ { print "user " $1 " " $2 " file is owned by " $5 } $3 ~ /^-....w/ \ { print "user " $1 " " $2 " file is group writeable" } $3 ~ /^-.......w/ \ { print "user " $1 " " $2 " file is other writeable" }' \ >> $OUTPUT if [ -s $OUTPUT ] ; then printf "\nChecking dot files.\n" cat $OUTPUT fi fi # Mailboxes should be owned by user and unreadable. # if checkyesno check_varmail; then ls -l /var/mail | sed 1d | \ awk '$3 != $9 \ { print "user " $9 " mailbox is owned by " $3 } $1 != "-rw-------" \ { print "user " $9 " mailbox is " $1 ", group " $4 }' > $OUTPUT if [ -s $OUTPUT ] ; then printf "\nChecking mailbox ownership.\n" cat $OUTPUT fi fi # NFS exports shouldn't be globally exported # if checkyesno check_nfs && [ -f /etc/exports ]; then awk '{ # ignore comments and blank lines if ($0 ~ /^\#/ || $0 ~ /^$/ ) next; readonly = 0; for (i = 2; i <= NF; ++i) { if ($i ~ /-ro/) readonly = 1; else if ($i !~ /^-/) next; } if (readonly) print "File system " $1 " globally exported, read-only." else print "File system " $1 " globally exported, read-write." }' < /etc/exports > $OUTPUT if [ -s $OUTPUT ] ; then printf "\nChecking for globally exported file systems.\n" cat $OUTPUT fi fi # Display any changes in setuid files and devices. # if checkyesno check_devices; then > $ERR (find / \( ! -fstype local -o -fstype fdesc -o -fstype kernfs \ -o -fstype procfs \) -a -prune -o \ \( \( -perm -u+s -a ! -type d \) -o \ \( -perm -g+s -a ! -type d \) -o \ -type b -o -type c \) -print0 | \ xargs -0 ls -ldgTq | sort +9 > $LIST) 2> $OUTPUT # Display any errors that occurred during system file walk. if [ -s $OUTPUT ] ; then printf "Setuid/device find errors:\n" >> $ERR cat $OUTPUT >> $ERR printf "\n" >> $ERR fi # Display any changes in the setuid file list. egrep -v '^[bc]' $LIST > $TMP1 if [ -s $TMP1 ] ; then # Check to make sure uudecode isn't setuid. if grep -w uudecode $TMP1 > /dev/null ; then printf "\nUudecode is setuid.\n" >> $ERR fi CUR=$backup_dir/setuid.current BACK=$backup_dir/setuid.backup if [ -s $CUR ] ; then if cmp -s $CUR $TMP1 ; then : else > $TMP2 join -110 -210 -v2 $CUR $TMP1 > $OUTPUT if [ -s $OUTPUT ] ; then printf "Setuid additions:\n" >> $ERR tee -a $TMP2 < $OUTPUT >> $ERR printf "\n" >> $ERR fi join -110 -210 -v1 $CUR $TMP1 > $OUTPUT if [ -s $OUTPUT ] ; then printf "Setuid deletions:\n" >> $ERR tee -a $TMP2 < $OUTPUT >> $ERR printf "\n" >> $ERR fi sort -k10 $TMP2 $CUR $TMP1 | \ sed -e 's/[ ][ ]*/ /g' | \ uniq -u > $OUTPUT if [ -s $OUTPUT ] ; then printf "Setuid changes:\n" >> $ERR column -t $OUTPUT >> $ERR printf "\n" >> $ERR fi backup_file update $TMP1 $CUR $BACK fi else printf "Setuid additions:\n" >> $ERR column -t $TMP1 >> $ERR printf "\n" >> $ERR backup_file add $TMP1 $CUR $BACK fi fi # Check for block and character disk devices that are readable or # writeable or not owned by root.operator. >$TMP1 DISKLIST="acd ccd cd ch fd hk hp mcd md ra rb rd rl rx rz \ sd se ss tz uk up vnd wd xd xy" # DISKLIST="$DISKLIST ct mt st wt" for i in $DISKLIST; do egrep "^b.*/${i}[0-9][0-9]*[a-p]$" $LIST >> $TMP1 egrep "^c.*/r${i}[0-9][0-9]*[a-p]$" $LIST >> $TMP1 done awk '$3 != "root" || $4 != "operator" || $1 !~ /.rw-r-----/ \ { printf "Disk %s is user %s, group %s, permissions %s.\n", \ $11, $3, $4, $1; }' < $TMP1 > $OUTPUT if [ -s $OUTPUT ] ; then printf "\nChecking disk ownership and permissions.\n" >> $ERR cat $OUTPUT >> $ERR printf "\n" >> $ERR fi # Display any changes in the device file list. egrep '^[bc]' $LIST | sort -k11 > $TMP1 if [ -s $TMP1 ] ; then CUR=$backup_dir/device.current BACK=$backup_dir/device.backup if [ -s $CUR ] ; then if cmp -s $CUR $TMP1 ; then : else > $TMP2 join -111 -211 -v2 $CUR $TMP1 > $OUTPUT if [ -s $OUTPUT ] ; then printf "Device additions:\n" >> $ERR tee -a $TMP2 < $OUTPUT >> $ERR printf "\n" >> $ERR fi join -111 -211 -v1 $CUR $TMP1 > $OUTPUT if [ -s $OUTPUT ] ; then printf "Device deletions:\n" >> $ERR tee -a $TMP2 < $OUTPUT >> $ERR printf "\n" >> $ERR fi # Report any block device change. Ignore # character devices, only the name is # significant. cat $TMP2 $CUR $TMP1 | \ sed -e '/^c/d' | \ sort -k11 | \ sed -e 's/[ ][ ]*/ /g' | \ uniq -u > $OUTPUT if [ -s $OUTPUT ] ; then printf "Block device changes:\n" >> $ERR column -t $OUTPUT >> $ERR printf "\n" >> $ERR fi backup_file update $TMP1 $CUR $BACK fi else printf "Device additions:\n" >> $ERR column -t $TMP1 >> $ERR printf "\n" >> $ERR backup_file add $TMP1 $CUR $BACK >> $ERR fi fi if [ -s $ERR ] ; then printf "\nChecking setuid files and devices:\n" cat $ERR printf "\n" fi fi # Check special files. # Check system binaries. # # Create the mtree tree specifications using: # # mtree -cx -pDIR -kcksum,gid,mode,nlink,size,link,time,uid > DIR.secure # chown root:wheel DIR.secure # chmod 600 DIR.secure # # Note, this is not complete protection against Trojan horsed binaries, as # the hacker can modify the tree specification to match the replaced binary. # For details on really protecting yourself against modified binaries, see # the mtree(8) manual page. # if checkyesno check_mtree; then mtree -e -p / -f /etc/mtree/special > $OUTPUT if [ -s $OUTPUT ]; then printf "\nChecking special files and directories.\n" cat $OUTPUT fi > $OUTPUT for file in /etc/mtree/*.secure; do [ $file = '/etc/mtree/*.secure' ] && continue tree=`sed -n -e '3s/.* //p' -e 3q $file` mtree -f $file -p $tree > $TMP1 if [ -s $TMP1 ]; then printf "\nChecking $tree:\n" >> $OUTPUT cat $TMP1 >> $OUTPUT fi done if [ -s $OUTPUT ]; then printf "\nChecking system binaries:\n" cat $OUTPUT fi fi CHANGELIST="" # Backup disklabels of available disks # if checkyesno check_disklabels; then # generate list of old disklabels and remove them ls -1d $backup_dir/disklabel.* 2>/dev/null | egrep -v '\.(backup|current)(,v)?$' > $LABELS xargs rm < $LABELS disks=`iostat -x | sed 1d | awk '$1 !~ /^[cfm]d/ { print $1; }'` for i in $disks; do dlf="$backup_dir/disklabel.$i" disklabel $i > $dlf 2>/dev/null done # append list of new disklabels, sort list ls -1d $backup_dir/disklabel.* 2>/dev/null | egrep -v '\.(backup|current)(,v)?$' >> $LABELS sort -u -o $LABELS $LABELS CHANGELIST=$LABELS fi # List of files that get backed up and checked for any modifications. Each # file is expected to have two backups, $backup_dir/file.{current,backup}. # Any changes cause the files to rotate. # if checkyesno check_changelist && [ -s /etc/changelist ] ; then CHANGELIST="/etc/changelist $CHANGELIST" fi if [ -n "$CHANGELIST" ]; then for file in `egrep -hv "^#|$MP" $CHANGELIST`; do # old changelist backup names OCUR=$backup_dir/${file##*/}.current OBACK=$backup_dir/${file##*/}.backup # new changelist backup names CUR=$backup_dir$file.current BACK=$backup_dir$file.backup # roll over old backups if [ ! -d ${CUR%/*} ]; then mkdir -p ${CUR%/*} fi if [ -f $OCUR -a ! -f $CUR ]; then mv $OCUR $CUR fi if [ -f $OCUR,v -a ! -f $CUR,v ]; then mv $OCUR,v $CUR,v fi if [ -f $OBACK -a ! -f $BACK ]; then mv $OBACK $BACK fi # and down to work if [ -f $file ]; then if [ -f $CUR ] ; then diff $CUR $file > $OUTPUT if [ -s $OUTPUT ] ; then printf "\n======\n%s diffs (OLD < > NEW)\n======\n" $file cat $OUTPUT backup_file update $file $CUR $BACK fi else printf "\n======\n%s added\n======\n" $file diff /dev/null $file backup_file add $file $CUR $BACK fi else if [ -f $CUR ]; then printf "\n======\n%s removed\n======\n" $file diff $CUR /dev/null backup_file remove $file $CUR $BACK fi fi done fi if [ -f /etc/security.local ]; then echo "" echo "Running /etc/security.local:" . /etc/security.local fi