security revision 1.13
1#!/bin/sh - 2# 3# $NetBSD: security,v 1.13 1996/01/14 00:58:25 pk Exp $ 4# from: @(#)security 8.1 (Berkeley) 6/9/93 5# 6 7PATH=/sbin:/usr/sbin:/bin:/usr/bin 8 9umask 077 10 11ERR=/tmp/_secure1.$$ 12TMP1=/tmp/_secure2.$$ 13TMP2=/tmp/_secure3.$$ 14TMP3=/tmp/_secure4.$$ 15LIST=/tmp/_secure5.$$ 16OUTPUT=/tmp/_secure6.$$ 17 18trap 'rm -f $ERR $TMP1 $TMP2 $TMP3 $LIST $OUTPUT' 0 19 20# Check the master password file syntax. 21MP=/etc/master.passwd 22awk -F: '{ 23 if ($0 ~ /^[ ]*$/) { 24 printf("Line %d is a blank line.\n", NR); 25 next; 26 } 27 if (NF != 10) 28 printf("Line %d has the wrong number of fields.\n", NR); 29 if ($1 !~ /^[A-Za-z0-9]*$/) 30 printf("Login %s has non-alphanumeric characters.\n", $1); 31 if (length($1) > 8) 32 printf("Login %s has more than 8 characters.\n", $1); 33 if ($2 == "") 34 printf("Login %s has no password.\n", $1); 35 if (length($2) != 13 && $2 != "" && ($10 ~ /.*sh$/ || $10 == "")) 36 printf("Login %s is off but still has a valid shell.\n", $1); 37 if ($3 == 0 && $1 != "root" && $1 != "toor") 38 printf("Login %s has a user id of 0.\n", $1); 39 if ($3 < 0) 40 printf("Login %s has a negative user id.\n", $1); 41 if ($4 < 0) 42 printf("Login %s has a negative group id.\n", $1); 43}' < $MP > $OUTPUT 44if [ -s $OUTPUT ] ; then 45 printf "\nChecking the $MP file:\n" 46 cat $OUTPUT 47fi 48 49awk -F: '{ print $1 }' $MP | sort | uniq -d > $OUTPUT 50if [ -s $OUTPUT ] ; then 51 printf "\n$MP has duplicate user names.\n" 52 column $OUTPUT 53fi 54 55awk -F: '{ print $1 " " $3 }' $MP | sort -n +1 | tee $TMP1 | 56uniq -d -f 1 | awk '{ print $2 }' > $TMP2 57if [ -s $TMP2 ] ; then 58 printf "\n$MP has duplicate user id's.\n" 59 while read uid; do 60 grep -w $uid $TMP1 61 done < $TMP2 | column 62fi 63 64# Backup the master password file; a special case, the normal backup 65# mechanisms also print out file differences and we don't want to do 66# that because this file has encrypted passwords in it. 67CUR=/var/backups/`basename $MP`.current 68BACK=/var/backups/`basename $MP`.backup 69if [ -s $CUR ] ; then 70 if cmp -s $CUR $MP; then 71 : 72 else 73 cp -p $CUR $BACK 74 cp -p $MP $CUR 75 chown root.wheel $CUR 76 fi 77else 78 cp -p $MP $CUR 79 chown root.wheel $CUR 80fi 81 82# Check the group file syntax. 83GRP=/etc/group 84awk -F: '{ 85 if ($0 ~ /^[ ]*$/) { 86 printf("Line %d is a blank line.\n", NR); 87 next; 88 } 89 if (NF != 4) 90 printf("Line %d has the wrong number of fields.\n", NR); 91 if ($1 !~ /^[A-za-z0-9]*$/) 92 printf("Group %s has non-alphanumeric characters.\n", $1); 93 if (length($1) > 8) 94 printf("Group %s has more than 8 characters.\n", $1); 95 if ($3 !~ /[0-9]*/) 96 printf("Login %s has a negative group id.\n", $1); 97}' < $GRP > $OUTPUT 98if [ -s $OUTPUT ] ; then 99 printf "\nChecking the $GRP file:\n" 100 cat $OUTPUT 101fi 102 103awk -F: '{ print $1 }' $GRP | sort | uniq -d > $OUTPUT 104if [ -s $OUTPUT ] ; then 105 printf "\n$GRP has duplicate group names.\n" 106 column $OUTPUT 107fi 108 109# Check for root paths, umask values in startup files. 110# The check for the root paths is problematical -- it's likely to fail 111# in other environments. Once the shells have been modified to warn 112# of '.' in the path, the path tests should go away. 113> $OUTPUT 114rhome=/root 115umaskset=no 116list="/etc/csh.cshrc /etc/csh.login ${rhome}/.cshrc ${rhome}/.login" 117for i in $list ; do 118 if [ -f $i ] ; then 119 if egrep umask $i > /dev/null ; then 120 umaskset=yes 121 fi 122 egrep umask $i | 123 awk '$2 % 100 < 20 \ 124 { print "Root umask is group writeable" } 125 $2 % 10 < 2 \ 126 { print "Root umask is other writeable" }' >> $OUTPUT 127 /bin/csh -f -s << end-of-csh > /dev/null 2>&1 128 unset path 129 source $i 130 /bin/ls -ldgT \$path > $TMP1 131end-of-csh 132 awk '{ 133 if ($10 ~ /^\.$/) { 134 print "The root path includes ."; 135 next; 136 } 137 } 138 $1 ~ /^d....w/ \ 139 { print "Root path directory " $10 " is group writeable." } \ 140 $1 ~ /^d.......w/ \ 141 { print "Root path directory " $10 " is other writeable." }' \ 142 < $TMP1 >> $OUTPUT 143 fi 144done 145if [ $umaskset = "no" -o -s $OUTPUT ] ; then 146 printf "\nChecking root csh paths, umask values:\n$list\n" 147 if [ -s $OUTPUT ]; then 148 cat $OUTPUT 149 fi 150 if [ $umaskset = "no" ] ; then 151 printf "\nRoot csh startup files do not set the umask.\n" 152 fi 153fi 154 155> $OUTPUT 156rhome=/root 157umaskset=no 158list="${rhome}/.profile" 159for i in $list; do 160 if [ -f $i ] ; then 161 if egrep umask $i > /dev/null ; then 162 umaskset=yes 163 fi 164 egrep umask $i | 165 awk '$2 % 100 < 20 \ 166 { print "Root umask is group writeable" } \ 167 $2 % 10 < 2 \ 168 { print "Root umask is other writeable" }' >> $OUTPUT 169 /bin/sh << end-of-sh > /dev/null 2>&1 170 PATH= 171 . $i 172 list=\`echo \$PATH | /usr/bin/sed -e 's/:/ /g'\` 173 /bin/ls -ldgT \$list > $TMP1 174end-of-sh 175 awk '{ 176 if ($10 ~ /^\.$/) { 177 print "The root path includes ."; 178 next; 179 } 180 } 181 $1 ~ /^d....w/ \ 182 { print "Root path directory " $10 " is group writeable." } \ 183 $1 ~ /^d.......w/ \ 184 { print "Root path directory " $10 " is other writeable." }' \ 185 < $TMP1 >> $OUTPUT 186 187 fi 188done 189if [ $umaskset = "no" -o -s $OUTPUT ] ; then 190 printf "\nChecking root sh paths, umask values:\n$list\n" 191 if [ -s $OUTPUT ]; then 192 cat $OUTPUT 193 fi 194 if [ $umaskset = "no" ] ; then 195 printf "\nRoot sh startup files do not set the umask.\n" 196 fi 197fi 198 199# Root and uucp should both be in /etc/ftpusers. 200if egrep root /etc/ftpusers > /dev/null ; then 201 : 202else 203 printf "\nRoot not listed in /etc/ftpusers file.\n" 204fi 205if egrep uucp /etc/ftpusers > /dev/null ; then 206 : 207else 208 printf "\nUucp not listed in /etc/ftpusers file.\n" 209fi 210 211# Uudecode should not be in the /etc/aliases file. 212if egrep 'uudecode|decode' /etc/aliases; then 213 printf "\nThere is an entry for uudecode in the /etc/aliases file.\n" 214fi 215 216# Files that should not have + signs. 217list="/etc/hosts.equiv /etc/hosts.lpd" 218for f in $list ; do 219 if [ -f $f ] && egrep '\+' $f > /dev/null ; then 220 printf "\nPlus sign in $f file.\n" 221 fi 222done 223 224# Check for special users with .rhosts files. Only root and toor should 225# have a .rhosts files. Also, .rhosts files should not plus signs. 226awk -F: '$1 != "root" && $1 != "toor" && \ 227 ($3 < 100 || $1 == "ftp" || $1 == "uucp") \ 228 { print $1 " " $6 }' /etc/passwd | 229while read uid homedir; do 230 if [ -f ${homedir}/.rhosts ] ; then 231 rhost=`ls -ldgT ${homedir}/.rhosts` 232 printf "$uid: $rhost\n" 233 fi 234done > $OUTPUT 235if [ -s $OUTPUT ] ; then 236 printf "\nChecking for special users with .rhosts files.\n" 237 cat $OUTPUT 238fi 239 240awk -F: '{ print $1 " " $6 }' /etc/passwd | \ 241while read uid homedir; do 242 if [ -f ${homedir}/.rhosts ] && \ 243 egrep '\+' ${homedir}/.rhosts > /dev/null ; then 244 printf "$uid: + in .rhosts file.\n" 245 fi 246done > $OUTPUT 247if [ -s $OUTPUT ] ; then 248 printf "\nChecking .rhosts files syntax.\n" 249 cat $OUTPUT 250fi 251 252# Check home directories. Directories should not be owned by someone else 253# or writeable. 254awk -F: '{ print $1 " " $6 }' /etc/passwd | \ 255while read uid homedir; do 256 if [ -d ${homedir}/ ] ; then 257 file=`ls -ldgT ${homedir}` 258 printf "$uid $file\n" 259 fi 260done | 261awk '$1 != $4 && $4 != "root" \ 262 { print "user " $1 " home directory is owned by " $4 } 263 $2 ~ /^-....w/ \ 264 { print "user " $1 " home directory is group writeable" } 265 $2 ~ /^-.......w/ \ 266 { print "user " $1 " home directory is other writeable" }' > $OUTPUT 267if [ -s $OUTPUT ] ; then 268 printf "\nChecking home directories.\n" 269 cat $OUTPUT 270fi 271 272# Files that should not be owned by someone else or readable. 273list=".netrc .rhosts" 274awk -F: '{ print $1 " " $6 }' /etc/passwd | \ 275while read uid homedir; do 276 for f in $list ; do 277 file=${homedir}/${f} 278 if [ -f $file ] ; then 279 printf "$uid $f `ls -ldgT $file`\n" 280 fi 281 done 282done | 283awk '$1 != $5 && $5 != "root" \ 284 { print "user " $1 " " $2 " file is owned by " $5 } 285 $3 ~ /^-...r/ \ 286 { print "user " $1 " " $2 " file is group readable" } 287 $3 ~ /^-......r/ \ 288 { print "user " $1 " " $2 " file is other readable" } 289 $3 ~ /^-....w/ \ 290 { print "user " $1 " " $2 " file is group writeable" } 291 $3 ~ /^-.......w/ \ 292 { print "user " $1 " " $2 " file is other writeable" }' > $OUTPUT 293 294# Files that should not be owned by someone else or writeable. 295list=".bashrc .cshrc .emacs .exrc .forward .klogin .login .logout \ 296 .profile .tcshrc" 297awk -F: '{ print $1 " " $6 }' /etc/passwd | \ 298while read uid homedir; do 299 for f in $list ; do 300 file=${homedir}/${f} 301 if [ -f $file ] ; then 302 printf "$uid $f `ls -ldgT $file`\n" 303 fi 304 done 305done | 306awk '$1 != $5 && $5 != "root" \ 307 { print "user " $1 " " $2 " file is owned by " $5 } 308 $3 ~ /^-....w/ \ 309 { print "user " $1 " " $2 " file is group writeable" } 310 $3 ~ /^-.......w/ \ 311 { print "user " $1 " " $2 " file is other writeable" }' >> $OUTPUT 312if [ -s $OUTPUT ] ; then 313 printf "\nChecking dot files.\n" 314 cat $OUTPUT 315fi 316 317# Mailboxes should be owned by user and unreadable. 318ls -l /var/mail | sed 1d | \ 319awk '$3 != $9 \ 320 { print "user " $9 " mailbox is owned by " $3 } 321 $1 != "-rw-------" \ 322 { print "user " $9 " mailbox is " $1 ", group " $4 }' > $OUTPUT 323if [ -s $OUTPUT ] ; then 324 printf "\nChecking mailbox ownership.\n" 325 cat $OUTPUT 326fi 327 328if [ -f /etc/exports ]; then 329 # File systems should not be globally exported. 330 awk '{ 331 readonly = 0; 332 for (i = 2; i <= NF; ++i) { 333 if ($i ~ /-ro/) 334 readonly = 1; 335 else if ($i !~ /^-/) 336 next; 337 } 338 if (readonly) 339 print "File system " $1 " globally exported, read-only." 340 else 341 print "File system " $1 " globally exported, read-write." 342 }' < /etc/exports > $OUTPUT 343 if [ -s $OUTPUT ] ; then 344 printf "\nChecking for globally exported file systems.\n" 345 cat $OUTPUT 346 fi 347fi 348 349# Display any changes in setuid files and devices. 350printf "\nChecking setuid files and devices:\n" 351(find / \( ! -fstype local -o -fstype fdesc -o -fstype kernfs \ 352 -o -fstype procfs \) -a -prune -o \ 353 \( -perm -u+s -o -perm -g+s -o ! -type d -a ! -type f -a ! -type l -a \ 354 ! -type s \) -print | \ 355sort | sed -e 's/^/ls -ldgT /' | sh > $LIST) 2> $OUTPUT 356 357# Display any errors that occurred during system file walk. 358if [ -s $OUTPUT ] ; then 359 printf "Setuid/device find errors:\n" 360 cat $OUTPUT 361 printf "\n" 362fi 363 364# Display any changes in the setuid file list. 365egrep -v '^[bc]' $LIST > $TMP1 366if [ -s $TMP1 ] ; then 367 # Check to make sure uudecode isn't setuid. 368 if grep -w uudecode $TMP1 > /dev/null ; then 369 printf "\nUudecode is setuid.\n" 370 fi 371 372 CUR=/var/backups/setuid.current 373 BACK=/var/backups/setuid.backup 374 375 if [ -s $CUR ] ; then 376 if cmp -s $CUR $TMP1 ; then 377 : 378 else 379 > $TMP2 380 join -110 -210 -v2 $CUR $TMP1 > $OUTPUT 381 if [ -s $OUTPUT ] ; then 382 printf "Setuid additions:\n" 383 tee -a $TMP2 < $OUTPUT 384 printf "\n" 385 fi 386 387 join -110 -210 -v1 $CUR $TMP1 > $OUTPUT 388 if [ -s $OUTPUT ] ; then 389 printf "Setuid deletions:\n" 390 tee -a $TMP2 < $OUTPUT 391 printf "\n" 392 fi 393 394 sort +9 $TMP2 $CUR $TMP1 | \ 395 sed -e 's/[ ][ ]*/ /g' | uniq -u > $OUTPUT 396 if [ -s $OUTPUT ] ; then 397 printf "Setuid changes:\n" 398 column -t $OUTPUT 399 printf "\n" 400 fi 401 402 cp $CUR $BACK 403 cp $TMP1 $CUR 404 fi 405 else 406 printf "Setuid additions:\n" 407 column -t $TMP1 408 printf "\n" 409 cp $TMP1 $CUR 410 fi 411fi 412 413# Check for block and character disk devices that are readable or writeable 414# or not owned by root.operator. 415>$TMP1 416DISKLIST="dk fd hd hk hp jb kra ra rb rd rl rx rz sd up wd" 417for i in $DISKLIST; do 418 egrep "^b.*/${i}[0-9][0-9]*[a-h]$" $LIST >> $TMP1 419 egrep "^c.*/r${i}[0-9][0-9]*[a-h]$" $LIST >> $TMP1 420done 421 422awk '$3 != "root" || $4 != "operator" || $1 !~ /.rw-r-----/ \ 423 { printf("Disk %s is user %s, group %s, permissions %s.\n", \ 424 $11, $3, $4, $1); }' < $TMP1 > $OUTPUT 425if [ -s $OUTPUT ] ; then 426 printf "\nChecking disk ownership and permissions.\n" 427 cat $OUTPUT 428 printf "\n" 429fi 430 431# Display any changes in the device file list. 432egrep '^[bc]' $LIST | sort +10 > $TMP1 433if [ -s $TMP1 ] ; then 434 CUR=/var/backups/device.current 435 BACK=/var/backups/device.backup 436 437 if [ -s $CUR ] ; then 438 if cmp -s $CUR $TMP1 ; then 439 : 440 else 441 > $TMP2 442 join -111 -211 -v2 $CUR $TMP1 > $OUTPUT 443 if [ -s $OUTPUT ] ; then 444 printf "Device additions:\n" 445 tee -a $TMP2 < $OUTPUT 446 printf "\n" 447 fi 448 449 join -111 -211 -v1 $CUR $TMP1 > $OUTPUT 450 if [ -s $OUTPUT ] ; then 451 printf "Device deletions:\n" 452 tee -a $TMP2 < $OUTPUT 453 printf "\n" 454 fi 455 456 # Report any block device change. Ignore character 457 # devices, only the name is significant. 458 cat $TMP2 $CUR $TMP1 | \ 459 sed -e '/^c/d' | \ 460 sort +10 | \ 461 sed -e 's/[ ][ ]*/ /g' | \ 462 uniq -u > $OUTPUT 463 if [ -s $OUTPUT ] ; then 464 printf "Block device changes:\n" 465 column -t $OUTPUT 466 printf "\n" 467 fi 468 469 cp $CUR $BACK 470 cp $TMP1 $CUR 471 fi 472 else 473 printf "Device additions:\n" 474 column -t $TMP1 475 printf "\n" 476 cp $TMP1 $CUR 477 fi 478fi 479 480# Check special files. 481# Check system binaries. 482# 483# Create the mtree tree specifications using: 484# 485# mtree -cx -pDIR -kcksum,gid,mode,nlink,size,link,time,uid > DIR.secure 486# chown root.wheel DIR.SECURE 487# chmod 600 DIR.SECURE 488# 489# Note, this is not complete protection against Trojan horsed binaries, as 490# the hacker can modify the tree specification to match the replaced binary. 491# For details on really protecting yourself against modified binaries, see 492# the mtree(8) manual page. 493if cd /etc/mtree; then 494 mtree -e -p / -f /etc/mtree/special > $OUTPUT 495 if [ -s $OUTPUT ] ; then 496 printf "\nChecking special files and directories.\n" 497 cat $OUTPUT 498 fi 499 500 > $OUTPUT 501 for file in *.secure; do 502 [ $file = '*.secure' ] && continue 503 tree=`sed -n -e '3s/.* //p' -e 3q $file` 504 mtree -f $file -p $tree > $TMP1 505 if [ -s $TMP1 ]; then 506 printf "\nChecking $tree:\n" >> $OUTPUT 507 cat $TMP1 >> $OUTPUT 508 fi 509 done 510 if [ -s $OUTPUT ] ; then 511 printf "\nChecking system binaries:\n" 512 cat $OUTPUT 513 fi 514fi 515 516# List of files that get backed up and checked for any modifications. Each 517# file is expected to have two backups, /var/backups/file.{current,backup}. 518# Any changes cause the files to rotate. 519if [ -s /etc/changelist ] ; then 520 for file in `cat /etc/changelist`; do 521 CUR=/var/backups/`basename $file`.current 522 BACK=/var/backups/`basename $file`.backup 523 if [ -s $file ]; then 524 if [ -s $CUR ] ; then 525 diff $CUR $file > $OUTPUT 526 if [ -s $OUTPUT ] ; then 527 printf "\n======\n%s diffs (OLD < > NEW)\n======\n" $file 528 cat $OUTPUT 529 cp -p $CUR $BACK 530 cp -p $file $CUR 531 chown root.wheel $CUR $BACK 532 fi 533 else 534 cp -p $file $CUR 535 chown root.wheel $CUR 536 fi 537 fi 538 done 539fi 540