security revision 1.33
1#!/bin/sh - 2# 3# $NetBSD: security,v 1.33 1998/09/14 19:42:42 tv Exp $ 4# from: @(#)security 8.1 (Berkeley) 6/9/93 5# 6 7PATH=/sbin:/usr/sbin:/bin:/usr/bin 8 9if [ -f /etc/rc.subr ]; then 10 . /etc/rc.subr 11else 12 echo "Can't read /etc/rc.subr; aborting." 13 exit 1; 14fi 15 16umask 077 17 18if [ -s /etc/security.conf ]; then 19 . /etc/security.conf 20fi 21 22SECUREDIR=/tmp/_securedir.$$ 23if ! mkdir $SECUREDIR; then 24 echo can not create $SECUREDIR. 25 exit 1 26fi 27 28if ! cd $SECUREDIR; then 29 echo can not chdir to $SECUREDIR. 30 exit 1 31fi 32 33ERR=secure1.$$ 34TMP1=secure2.$$ 35TMP2=secure3.$$ 36MPBYUID=secure4.$$ 37MPBYPATH=secure5.$$ 38LIST=secure6.$$ 39OUTPUT=secure7.$$ 40LABELS=secure8.$$ 41 42trap '/bin/rm -rf $SECUREDIR ; exit 0' 0 2 3 43 44MP=/etc/master.passwd 45 46# these is used several times. 47awk -F: '{ print $1 " " $3 }' $MP | sort -k2n > $MPBYUID 48awk -F: '{ print $1 " " $9 }' $MP | sort -k2 > $MPBYPATH 49 50# Check the master password file syntax. 51# 52if checkyesno check_passwd; then 53 awk ' 54 BEGIN { 55 while ( getline < "/etc/shells" > 0 ) { 56 if ($LINE ~ /^\#/ || $LINE ~ /^$/ ) 57 continue; 58 shells[$1]++; 59 } 60 FS=":"; 61 } 62 63 { 64 if ($0 ~ /^[ ]*$/) { 65 printf "Line %d is a blank line.\n", NR; 66 next; 67 } 68 if (NF != 10) 69 printf "Line %d has the wrong number of fields.\n", NR; 70 if ($1 !~ /^[A-Za-z0-9]*$/) 71 printf "Login %s has non-alphanumeric characters.\n", 72 $1; 73 if (length($1) > 8) 74 printf "Login %s has more than 8 characters.\n", $1; 75 if ($2 == "") 76 printf "Login %s has no password.\n", $1; 77 if (length($2) != 13 && length($2) != 20 && $2 != "") { 78 if ($10 == "" || shells[$10]) 79 printf "Login %s is off but still has a valid shell (%s)\n", 80 $1, $10; 81 } else if (! shells[$10]) 82 printf "Login %s does not have a valid shell (%s)\n", 83 $1, $10; 84 if ($3 == 0 && $1 != "root" && $1 != "toor") 85 printf "Login %s has a user id of 0.\n", $1; 86 if ($3 < 0) 87 printf "Login %s has a negative user id.\n", $1; 88 if ($4 < 0) 89 printf "Login %s has a negative group id.\n", $1; 90 }' < $MP > $OUTPUT 91 if [ -s $OUTPUT ] ; then 92 printf "\nChecking the $MP file:\n" 93 cat $OUTPUT 94 fi 95 96 awk -F: '{ print $1 }' $MP | sort | uniq -d > $OUTPUT 97 if [ -s $OUTPUT ] ; then 98 printf "\n$MP has duplicate user names.\n" 99 column $OUTPUT 100 fi 101 102 < $MPBYUID uniq -d -f 1 | awk '{ print $2 }' > $TMP2 103 if [ -s $TMP2 ] ; then 104 printf "\n$MP has duplicate user id's.\n" 105 while read uid; do 106 grep -w $uid $MPBYUID 107 done < $TMP2 | column 108 fi 109fi 110 111# Backup the master password file; a special case, the normal backup 112# mechanisms also print out file differences and we don't want to do 113# that because this file has encrypted passwords in it. 114# 115CUR=/var/backups/`basename $MP`.current 116BACK=/var/backups/`basename $MP`.backup 117if [ -s $CUR ] ; then 118 if cmp -s $CUR $MP; then 119 : 120 else 121 cp -p $CUR $BACK 122 cp -p $MP $CUR 123 chown root.wheel $CUR 124 fi 125else 126 cp -p $MP $CUR 127 chown root.wheel $CUR 128fi 129 130# Check the group file syntax. 131# 132if checkyesno check_group; then 133 GRP=/etc/group 134 awk -F: '{ 135 if ($0 ~ /^[ ]*$/) { 136 printf "Line %d is a blank line.\n", NR; 137 next; 138 } 139 if (NF != 4) 140 printf "Line %d has the wrong number of fields.\n", NR; 141 if ($1 !~ /^[A-za-z0-9]*$/) 142 printf "Group %s has non-alphanumeric characters.\n", 143 $1; 144 if (length($1) > 8) 145 printf "Group %s has more than 8 characters.\n", $1; 146 if ($3 !~ /[0-9]*/) 147 printf "Login %s has a negative group id.\n", $1; 148 }' < $GRP > $OUTPUT 149 if [ -s $OUTPUT ] ; then 150 printf "\nChecking the $GRP file:\n" 151 cat $OUTPUT 152 fi 153 154 awk -F: '{ print $1 }' $GRP | sort | uniq -d > $OUTPUT 155 if [ -s $OUTPUT ] ; then 156 printf "\n$GRP has duplicate group names.\n" 157 column $OUTPUT 158 fi 159fi 160 161# Check for root paths, umask values in startup files. 162# The check for the root paths is problematical -- it's likely to fail 163# in other environments. Once the shells have been modified to warn 164# of '.' in the path, the path tests should go away. 165# 166if checkyesno check_rootdotfiles; then 167 > $OUTPUT 168 rhome=`csh -fc "echo ~root"` 169 umaskset=no 170 list="/etc/csh.cshrc /etc/csh.login ${rhome}/.cshrc ${rhome}/.login" 171 for i in $list ; do 172 if [ -f $i ] ; then 173 if egrep umask $i > /dev/null ; then 174 umaskset=yes 175 fi 176 egrep umask $i | 177 awk '$2 % 100 < 20 \ 178 { print "\tRoot umask is group writeable" } 179 $2 % 10 < 2 \ 180 { print "\tRoot umask is other writeable" }' \ 181 >> $OUTPUT 182 SAVE_PATH=$PATH 183 unset PATH 184 /bin/csh -f -s << end-of-csh > /dev/null 2>&1 185 source $i 186 /bin/ls -ldgT \$path > $TMP1 187end-of-csh 188 PATH=$SAVE_PATH 189 awk '{ 190 if ($10 ~ /^\.$/) { 191 print "\tThe root path includes ."; 192 next; 193 } 194 } 195 $1 ~ /^d....w/ \ 196 { print "\tRoot path directory " $10 " is group writeable." } \ 197 $1 ~ /^d.......w/ \ 198 { print "\tRoot path directory " $10 " is other writeable." }' \ 199 < $TMP1 >> $OUTPUT 200 fi 201 done 202 if [ $umaskset = "no" -o -s $OUTPUT ] ; then 203 printf "\nChecking root csh paths, umask values:\n$list\n\n" 204 if [ -s $OUTPUT ]; then 205 cat $OUTPUT 206 fi 207 if [ $umaskset = "no" ] ; then 208 printf "\tRoot csh startup files do not set the umask.\n" 209 fi 210 fi 211 212 > $OUTPUT 213 rhome=/root 214 umaskset=no 215 list="/etc/profile ${rhome}/.profile" 216 for i in $list; do 217 if [ -f $i ] ; then 218 if egrep umask $i > /dev/null ; then 219 umaskset=yes 220 fi 221 egrep umask $i | 222 awk '$2 % 100 < 20 \ 223 { print "\tRoot umask is group writeable" } \ 224 $2 % 10 < 2 \ 225 { print "\tRoot umask is other writeable" }' \ 226 >> $OUTPUT 227 SAVE_PATH=$PATH 228 unset PATH 229 /bin/sh << end-of-sh > /dev/null 2>&1 230 . $i 231 list=\`echo \$PATH | /usr/bin/sed -e \ 232 's/^:/.:/;s/:$/:./;s/::/:.:/g;s/:/ /g'\` 233 /bin/ls -ldgT \$list > $TMP1 234end-of-sh 235 PATH=$SAVE_PATH 236 awk '{ 237 if ($10 ~ /^\.$/) { 238 print "\tThe root path includes ."; 239 next; 240 } 241 } 242 $1 ~ /^d....w/ \ 243 { print "\tRoot path directory " $10 " is group writeable." } \ 244 $1 ~ /^d.......w/ \ 245 { print "\tRoot path directory " $10 " is other writeable." }' \ 246 < $TMP1 >> $OUTPUT 247 248 fi 249 done 250 if [ $umaskset = "no" -o -s $OUTPUT ] ; then 251 printf "\nChecking root sh paths, umask values:\n$list\n" 252 if [ -s $OUTPUT ]; then 253 cat $OUTPUT 254 fi 255 if [ $umaskset = "no" ] ; then 256 printf "\tRoot sh startup files do not set the umask.\n" 257 fi 258 fi 259fi 260 261# Root and uucp should both be in /etc/ftpusers. 262# 263if checkyesno check_ftpusers; then 264 > $OUTPUT 265 list="uucp "`awk '$2 == 0 { print $1 }' $MPBYUID` 266 for i in $list; do 267 if /usr/libexec/ftpd -C $i ; then 268 printf "\t$i is not denied\n" >> $OUTPUT 269 fi 270 done 271 if [ -s $OUTPUT ]; then 272 printf "\nChecking the /etc/ftpusers configuration:\n" 273 cat $OUTPUT 274 fi 275fi 276 277# Uudecode should not be in the /etc/aliases file. 278# 279if checkyesno check_aliases; then 280 if egrep '^[^#]*(uudecode|decode).*\|' /etc/aliases; then 281 printf "\nEntry for uudecode in /etc/aliases file.\n" 282 fi 283fi 284 285# Files that should not have + signs. 286# 287if checkyesno check_rhosts; then 288 list="/etc/hosts.equiv /etc/hosts.lpd" 289 for f in $list ; do 290 if [ -f $f ] && egrep '\+' $f > /dev/null ; then 291 printf "\nPlus sign in $f file.\n" 292 fi 293 done 294 295 # Check for special users with .rhosts files. Only root and toor should 296 # have .rhosts files. Also, .rhosts files should not have plus signs. 297 awk -F: '$1 != "root" && $1 != "toor" && \ 298 ($3 < 100 || $1 == "ftp" || $1 == "uucp") \ 299 { print $1 " " $9 }' $MP | 300 sort -k2 | 301 while read uid homedir; do 302 if [ -f ${homedir}/.rhosts ] ; then 303 rhost=`ls -ldgT ${homedir}/.rhosts` 304 printf "$uid: $rhost\n" 305 fi 306 done > $OUTPUT 307 if [ -s $OUTPUT ] ; then 308 printf "\nChecking for special users with .rhosts files.\n" 309 cat $OUTPUT 310 fi 311 312 while read uid homedir; do 313 if [ -f ${homedir}/.rhosts ] && \ 314 egrep '\+' ${homedir}/.rhosts > /dev/null ; then 315 printf "$uid: + in .rhosts file.\n" 316 fi 317 done < $MPBYPATH > $OUTPUT 318 if [ -s $OUTPUT ] ; then 319 printf "\nChecking .rhosts files syntax.\n" 320 cat $OUTPUT 321 fi 322fi 323 324# Check home directories. Directories should not be owned by someone else 325# or writeable. 326# 327if checkyesno check_homes; then 328 while read uid homedir; do 329 if [ -d ${homedir}/ ] ; then 330 file=`ls -ldgT ${homedir}` 331 printf "$uid $file\n" 332 fi 333 done < $MPBYPATH | 334 awk '$1 != $4 && $4 != "root" \ 335 { print "user " $1 " home directory is owned by " $4 } 336 $2 ~ /^-....w/ \ 337 { print "user " $1 " home directory is group writeable" } 338 $2 ~ /^-.......w/ \ 339 { print "user " $1 " home directory is other writeable" }' \ 340 > $OUTPUT 341 if [ -s $OUTPUT ] ; then 342 printf "\nChecking home directories.\n" 343 cat $OUTPUT 344 fi 345 346 # Files that should not be owned by someone else or readable. 347 list=".Xauthority .netrc" 348 while read uid homedir; do 349 for f in $list ; do 350 file=${homedir}/${f} 351 if [ -f $file ] ; then 352 printf "$uid $f `ls -ldgT $file`\n" 353 fi 354 done 355 done < $MPBYPATH | 356 awk '$1 != $5 && $5 != "root" \ 357 { print "user " $1 " " $2 " file is owned by " $5 } 358 $3 ~ /^-...r/ \ 359 { print "user " $1 " " $2 " file is group readable" } 360 $3 ~ /^-......r/ \ 361 { print "user " $1 " " $2 " file is other readable" } 362 $3 ~ /^-....w/ \ 363 { print "user " $1 " " $2 " file is group writeable" } 364 $3 ~ /^-.......w/ \ 365 { print "user " $1 " " $2 " file is other writeable" }' \ 366 > $OUTPUT 367 368 # Files that should not be owned by someone else or writeable. 369 list=".bash_history .bash_login .bash_logout .bash_profile .bashrc \ 370 .cshrc .emacs .exrc .forward .history .klogin .login .logout \ 371 .profile .qmail .rc_history .rhosts .tcshrc .twmrc .xinitrc \ 372 .xsession" 373 while read uid homedir; do 374 for f in $list ; do 375 file=${homedir}/${f} 376 if [ -f $file ] ; then 377 printf "$uid $f `ls -ldgT $file`\n" 378 fi 379 done 380 done < $MPBYPATH | 381 awk '$1 != $5 && $5 != "root" \ 382 { print "user " $1 " " $2 " file is owned by " $5 } 383 $3 ~ /^-....w/ \ 384 { print "user " $1 " " $2 " file is group writeable" } 385 $3 ~ /^-.......w/ \ 386 { print "user " $1 " " $2 " file is other writeable" }' \ 387 >> $OUTPUT 388 if [ -s $OUTPUT ] ; then 389 printf "\nChecking dot files.\n" 390 cat $OUTPUT 391 fi 392fi 393 394# Mailboxes should be owned by user and unreadable. 395# 396if checkyesno check_varmail; then 397 ls -l /var/mail | sed 1d | \ 398 awk '$3 != $9 \ 399 { print "user " $9 " mailbox is owned by " $3 } 400 $1 != "-rw-------" \ 401 { print "user " $9 " mailbox is " $1 ", group " $4 }' > $OUTPUT 402 if [ -s $OUTPUT ] ; then 403 printf "\nChecking mailbox ownership.\n" 404 cat $OUTPUT 405 fi 406fi 407 408# NFS exports shouldn't be globally exported 409# 410if checkyesno check_nfs && [ -f /etc/exports ]; then 411 awk '{ 412 # ignore comments and blank lines 413 if ($LINE ~ /^\#/ || $LINE ~ /^$/ ) 414 next; 415 416 readonly = 0; 417 for (i = 2; i <= NF; ++i) { 418 if ($i ~ /-ro/) 419 readonly = 1; 420 else if ($i !~ /^-/) 421 next; 422 } 423 if (readonly) 424 print "File system " $1 " globally exported, read-only." 425 else 426 print "File system " $1 " globally exported, read-write." 427 }' < /etc/exports > $OUTPUT 428 if [ -s $OUTPUT ] ; then 429 printf "\nChecking for globally exported file systems.\n" 430 cat $OUTPUT 431 fi 432fi 433 434# Display any changes in setuid files and devices. 435# 436if checkyesno check_devices; then 437 > $ERR 438 (find / \( ! -fstype local -o -fstype fdesc -o -fstype kernfs \ 439 -o -fstype procfs \) -a -prune -o \ 440 \( \( -perm -u+s -a ! -type d \) -o \ 441 \( -perm -g+s -a ! -type d \) -o \ 442 -type b -o -type c \) -print0 | \ 443 xargs -0 ls -ldgTq | sort +9 > $LIST) 2> $OUTPUT 444 445 # Display any errors that occurred during system file walk. 446 if [ -s $OUTPUT ] ; then 447 printf "Setuid/device find errors:\n" >> $ERR 448 cat $OUTPUT >> $ERR 449 printf "\n" >> $ERR 450 fi 451 452 # Display any changes in the setuid file list. 453 egrep -v '^[bc]' $LIST > $TMP1 454 if [ -s $TMP1 ] ; then 455 # Check to make sure uudecode isn't setuid. 456 if grep -w uudecode $TMP1 > /dev/null ; then 457 printf "\nUudecode is setuid.\n" >> $ERR 458 fi 459 460 CUR=/var/backups/setuid.current 461 BACK=/var/backups/setuid.backup 462 463 if [ -s $CUR ] ; then 464 if cmp -s $CUR $TMP1 ; then 465 : 466 else 467 > $TMP2 468 join -110 -210 -v2 $CUR $TMP1 > $OUTPUT 469 if [ -s $OUTPUT ] ; then 470 printf "Setuid additions:\n" >> $ERR 471 tee -a $TMP2 < $OUTPUT >> $ERR 472 printf "\n" >> $ERR 473 fi 474 475 join -110 -210 -v1 $CUR $TMP1 > $OUTPUT 476 if [ -s $OUTPUT ] ; then 477 printf "Setuid deletions:\n" >> $ERR 478 tee -a $TMP2 < $OUTPUT >> $ERR 479 printf "\n" >> $ERR 480 fi 481 482 sort -k10 $TMP2 $CUR $TMP1 | \ 483 sed -e 's/[ ][ ]*/ /g' | \ 484 uniq -u > $OUTPUT 485 if [ -s $OUTPUT ] ; then 486 printf "Setuid changes:\n" >> $ERR 487 column -t $OUTPUT >> $ERR 488 printf "\n" >> $ERR 489 fi 490 491 cp $CUR $BACK 492 cp $TMP1 $CUR 493 fi 494 else 495 printf "Setuid additions:\n" >> $ERR 496 column -t $TMP1 >> $ERR 497 printf "\n" >> $ERR 498 cp $TMP1 $CUR 499 fi 500 fi 501 502 # Check for block and character disk devices that are readable or 503 # writeable or not owned by root.operator. 504 >$TMP1 505 DISKLIST="acd ccd cd ch fd hk hp mcd md ra rb rd rl rx rz \ 506 sd se ss tz uk up vnd wd xd xy" 507# DISKLIST="$DISKLIST ct mt st wt" 508 for i in $DISKLIST; do 509 egrep "^b.*/${i}[0-9][0-9]*[a-p]$" $LIST >> $TMP1 510 egrep "^c.*/r${i}[0-9][0-9]*[a-p]$" $LIST >> $TMP1 511 done 512 513 awk '$3 != "root" || $4 != "operator" || $1 !~ /.rw-r-----/ \ 514 { printf "Disk %s is user %s, group %s, permissions %s.\n", \ 515 $11, $3, $4, $1; }' < $TMP1 > $OUTPUT 516 if [ -s $OUTPUT ] ; then 517 printf "\nChecking disk ownership and permissions.\n" >> $ERR 518 cat $OUTPUT >> $ERR 519 printf "\n" >> $ERR 520 fi 521 522 # Display any changes in the device file list. 523 egrep '^[bc]' $LIST | sort -k11 > $TMP1 524 if [ -s $TMP1 ] ; then 525 CUR=/var/backups/device.current 526 BACK=/var/backups/device.backup 527 528 if [ -s $CUR ] ; then 529 if cmp -s $CUR $TMP1 ; then 530 : 531 else 532 > $TMP2 533 join -111 -211 -v2 $CUR $TMP1 > $OUTPUT 534 if [ -s $OUTPUT ] ; then 535 printf "Device additions:\n" >> $ERR 536 tee -a $TMP2 < $OUTPUT >> $ERR 537 printf "\n" >> $ERR 538 fi 539 540 join -111 -211 -v1 $CUR $TMP1 > $OUTPUT 541 if [ -s $OUTPUT ] ; then 542 printf "Device deletions:\n" >> $ERR 543 tee -a $TMP2 < $OUTPUT >> $ERR 544 printf "\n" >> $ERR 545 fi 546 547 # Report any block device change. Ignore 548 # character devices, only the name is 549 # significant. 550 cat $TMP2 $CUR $TMP1 | \ 551 sed -e '/^c/d' | \ 552 sort -k11 | \ 553 sed -e 's/[ ][ ]*/ /g' | \ 554 uniq -u > $OUTPUT 555 if [ -s $OUTPUT ] ; then 556 printf "Block device changes:\n" >> $ERR 557 column -t $OUTPUT >> $ERR 558 printf "\n" >> $ERR 559 fi 560 561 cp $CUR $BACK 562 cp $TMP1 $CUR 563 fi 564 else 565 printf "Device additions:\n" >> $ERR 566 column -t $TMP1 >> $ERR 567 printf "\n" >> $ERR 568 cp $TMP1 $CUR >> $ERR 569 fi 570 fi 571 if [ -s $ERR ] ; then 572 printf "\nChecking setuid files and devices:\n" 573 cat $ERR 574 printf "\n" 575 fi 576fi 577 578# Check special files. 579# Check system binaries. 580# 581# Create the mtree tree specifications using: 582# 583# mtree -cx -pDIR -kcksum,gid,mode,nlink,size,link,time,uid > DIR.secure 584# chown root.wheel DIR.secure 585# chmod 600 DIR.secure 586# 587# Note, this is not complete protection against Trojan horsed binaries, as 588# the hacker can modify the tree specification to match the replaced binary. 589# For details on really protecting yourself against modified binaries, see 590# the mtree(8) manual page. 591# 592if checkyesno check_mtree; then 593 mtree -e -p / -f /etc/mtree/special > $OUTPUT 594 if [ -s $OUTPUT ]; then 595 printf "\nChecking special files and directories.\n" 596 cat $OUTPUT 597 fi 598 599 > $OUTPUT 600 for file in /etc/mtree/*.secure; do 601 [ $file = '/etc/mtree/*.secure' ] && continue 602 tree=`sed -n -e '3s/.* //p' -e 3q $file` 603 mtree -f $file -p $tree > $TMP1 604 if [ -s $TMP1 ]; then 605 printf "\nChecking $tree:\n" >> $OUTPUT 606 cat $TMP1 >> $OUTPUT 607 fi 608 done 609 if [ -s $OUTPUT ]; then 610 printf "\nChecking system binaries:\n" 611 cat $OUTPUT 612 fi 613fi 614 615CHANGELIST="" 616 617# Backup disklabels of available disks 618# 619if checkyesno check_disklabels; then 620 # generate list of old disklabels and remove them 621 ls -1d /var/backups/disklabel.* 2>/dev/null | 622 egrep -v '\.(backup|current)$' > $LABELS 623 xargs rm < $LABELS 624 625 disks=`iostat -x | sed 1d | awk '$1 !~ /^[mf]d/ { print $1; }'` 626 for i in $disks; do 627 dlf="/var/backups/disklabel.$i" 628 disklabel $i > $dlf 2>/dev/null 629 done 630 631 # append list of new disklabels, sort list 632 ls -1d /var/backups/disklabel.* 2>/dev/null | 633 egrep -v '\.(backup|current)$' >> $LABELS 634 sort -u -o $LABELS $LABELS 635 CHANGELIST=$LABELS 636fi 637 638# List of files that get backed up and checked for any modifications. Each 639# file is expected to have two backups, /var/backups/file.{current,backup}. 640# Any changes cause the files to rotate. 641# 642if checkyesno check_changelist && [ -s /etc/changelist ] ; then 643 CHANGELIST="/etc/changelist $CHANGELIST" 644fi 645 646if [ -n "$CHANGELIST" ]; then 647 for file in `egrep -hv "^#|$MP" $CHANGELIST`; do 648 CUR=/var/backups/`basename $file`.current 649 BACK=/var/backups/`basename $file`.backup 650 if [ -f $file ]; then 651 if [ -f $CUR ] ; then 652 diff $CUR $file > $OUTPUT 653 if [ -s $OUTPUT ] ; then 654 printf "\n======\n%s diffs (OLD < > NEW)\n======\n" $file 655 cat $OUTPUT 656 mv -f $CUR $BACK 657 cp -p $file $CUR 658 chown root.wheel $CUR 659 fi 660 else 661 printf "\n======\n%s added\n======\n" $file 662 diff /dev/null $file 663 cp -p $file $CUR 664 chown root.wheel $CUR 665 fi 666 else 667 if [ -f $CUR ]; then 668 printf "\n======\n%s removed\n======\n" $file 669 diff $CUR /dev/null 670 mv -f $CUR $BACK 671 fi 672 fi 673 done 674fi 675