Overflow buffer Heap - Output AddressSanitizer: cosa è necessario per sfruttare questa condizione?

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11

Questo è l'output di AddressSanitizer, per input diversi ottengo errori READ e WRITE. Dal punto di vista dell'overflow del buffer dell'heap che sono più interessanti? Voglio eseguire il mio shellcode. Qualcuno può interpretare questo output AndressSanitizer in un modo più "umano" comprensibile?

LEGGI esempio: 

==24222== ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000010000 at pc 0x4022bd bp 0x7fff9b142e90 sp 0x7fff9b142e88
READ of size 1 at 0x602000010000 thread T0
    #0 0x4022bc (/home/user/final/apngdis-2.5.orig/apngdis+0x4022bc)
    #1 0x40619a (/home/user/final/apngdis-2.5.orig/apngdis+0x40619a)
    #2 0x4012cd (/home/user/final/apngdis-2.5.orig/apngdis+0x4012cd)
    #3 0x7f677aadfec4 (/lib/x86_64-linux-gnu/libc-2.19.so+0x21ec4)
    #4 0x401734 (/home/user/final/apngdis-2.5.orig/apngdis+0x401734)
0x602000010000 is located 0 bytes to the right of 192-byte region [0x60200000ff40,0x602000010000)
allocated by thread T0 here:
    #0 0x7f677b0b141a (/usr/lib/x86_64-linux-gnu/libasan.so.0.0.0+0x1541a)
    #1 0x4059bb (/home/user/final/apngdis-2.5.orig/apngdis+0x4059bb)
Shadow bytes around the buggy address:
  0x0c047fff9fb0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9fc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9fd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9fe0: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
  0x0c047fff9ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c047fffa000:[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa010: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa020: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:     fa
  Heap righ redzone:     fb
  Freed Heap region:     fd
  Stack left redzone:    f1
  Stack mid redzone:     f2
  Stack right redzone:   f3
  Stack partial redzone: f4
  Stack after return:    f5
  Stack use after scope: f8
  Global redzone:        f9
  Global init order:     f6
  Poisoned by user:      f7
  ASan internal:         fe
==24222== ABORTING

Di seguito è riportato GDB Output

Questo overflow di heap è sfruttabile? Cosa dovrei cercare nel codice? Puoi dare qualche esempio con frammenti di codice? 

Starting program: /home/user/final/apngdis-2.5.orig/apngdis crash.png

APNG Disassembler 2.5

Reading 'crash.png'...

Breakpoint 2, unpack (zstream=..., dst=dst@entry=0x6e1910 "", dst_size=dst_size@entry=192, src=src@entry=0x6e19e0 "x2b670", src_size=src_size@entry=14, h=2147483651, 
    rowbytes=rowbytes@entry=63, bpp=1 '
root@user-lap:~/final/apngdis-2.5.orig# export ASAN_SYMBOLIZER_PATH=/usr/bin/llvm-symbolizer-3.4 
root@user-lap:~/final/apngdis-2.5.orig# ASAN_OPTIONS=symbolize=1 ./apngdis crash.png 

APNG Disassembler 2.5

Reading 'crash.png'...
=================================================================
==25265== ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000010000 at pc 0x41c07d bp 0x7ffc560b3f20 sp 0x7ffc560b3f18
READ of size 1 at 0x602000010000 thread T0
    #0 0x41c07c in unpack /home/user/final/apngdis-2.5.orig/apngdis.c:185
    #1 0x41ff5a in LoadAPNG /home/user/final/apngdis-2.5.orig/apngdis.c:846
    #2 0x40281d in main /home/user/final/apngdis-2.5.orig/apngdis.c:1208
    #3 0x7fb4ca7e4ec4 (/lib/x86_64-linux-gnu/libc.so.6+0x21ec4)
    #4 0x402c84 in _start (/home/user/final/apngdis-2.5.orig/apngdis+0x402c84)
0x602000010000 is located 0 bytes to the right of 192-byte region [0x60200000ff40,0x602000010000)
allocated by thread T0 here:
    #0 0x412c0a in __interceptor_malloc (/home/user/final/apngdis-2.5.orig/apngdis+0x412c0a)
    #1 0x41f77b in LoadAPNG /home/user/final/apngdis-2.5.orig/apngdis.c:635
SUMMARY: AddressSanitizer: heap-buffer-overflow /home/user/final/apngdis-2.5.orig/apngdis.c:185 unpack
Shadow bytes around the buggy address:
  0x0c047fff9fb0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9fc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9fd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9fe0: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
  0x0c047fff9ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c047fffa000:[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa010: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa020: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:     fa
  Heap righ redzone:     fb
  Freed Heap region:     fd
  Stack left redzone:    f1
  Stack mid redzone:     f2
  Stack right redzone:   f3
  Stack partial redzone: f4
  Stack after return:    f5
  Stack use after scope: f8
  Global redzone:        f9
  Global init order:     f6
  Poisoned by user:      f7
  ASan internal:         fe
==25265== ABORTING

1') at apngdis.c:171
171 {
(gdb) 
(gdb) 
(gdb) l
166       row[i] += row[i-bpp];
167   }
168 }
169 
170 void unpack(z_stream zstream, unsigned char * dst, unsigned int dst_size, unsigned char * src, unsigned int src_size, unsigned int h, unsigned int rowbytes, unsigned char bpp)
171 {
172   unsigned int    j;
173   unsigned char * row = dst;
174   unsigned char * prev_row = NULL;
175 
(gdb) l
176   zstream.next_out  = dst;
177   zstream.avail_out = dst_size;
178   zstream.next_in   = src;
179   zstream.avail_in  = src_size;
180   inflate(&zstream, Z_FINISH);
181   inflateReset(&zstream);
182 
183   for (j=0; j<h; j++)
184   {
185     switch (*row++) 
(gdb) l
186     {
187       case 0: break;
188       case 1: read_sub_row(row, rowbytes, bpp); break;
189       case 2: read_up_row(row, prev_row, rowbytes, bpp); break;
190       case 3: read_average_row(row, prev_row, rowbytes, bpp); break;
191       case 4: read_paeth_row(row, prev_row, rowbytes, bpp); break;
192     }
193     prev_row = row;
194     row += rowbytes;
195   }
(gdb) cont
Continuing.

Program received signal SIGSEGV, Segmentation fault.
unpack (zstream=..., dst=dst@entry=0x6e1910 "
==2720== ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60ae0003a81c at pc 0x41ee70 bp 0x7ffc84d157d0 sp 0x7ffc84d157c8
WRITE of size 4 at 0x60ae0003a81c thread T0
    #0 0x41ee6f in compose6 /home/user/final/apngdis-2.5.orig/apngdis.c:475
    #1 0x420025 in LoadAPNG /home/user/final/apngdis-2.5.orig/apngdis.c:853
    #2 0x40281d in main /home/user/final/apngdis-2.5.orig/apngdis.c:1208
    #3 0x7f4942135ec4 (/lib/x86_64-linux-gnu/libc.so.6+0x21ec4)
    #4 0x402c84 in _start (/home/user/final/apngdis-2.5.orig/apngdis+0x402c84)
0x60ae0003a81c is located 0 bytes to the right of 114716-byte region [0x60ae0001e800,0x60ae0003a81c)
allocated by thread T0 here:
    #0 0x412c0a in __interceptor_malloc (/home/user/final/apngdis-2.5.orig/apngdis+0x412c0a)
    #1 0x41f746 in LoadAPNG /home/user/final/apngdis-2.5.orig/apngdis.c:633
SUMMARY: AddressSanitizer: heap-buffer-overflow /home/user/final/apngdis-2.5.orig/apngdis.c:474 compose6
Shadow bytes around the buggy address:
  0x0c163ffff4b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c163ffff4c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c163ffff4d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c163ffff4e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c163ffff4f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c163ffff500: 00 00 00[04]fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c163ffff510: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c163ffff520: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c163ffff530: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c163ffff540: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c163ffff550: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:     fa
  Heap righ redzone:     fb
  Freed Heap region:     fd
  Stack left redzone:    f1
  Stack mid redzone:     f2
  Stack right redzone:   f3
  Stack partial redzone: f4
  Stack after return:    f5
  Stack use after scope: f8
  Global redzone:        f9
  Global init order:     f6
  Poisoned by user:      f7
  ASan internal:         fe
==2720== ABORTING

37777356", '7' <repeats 17 times>, "ϗ{mfca'''00H$2\t
root@laptop:~/security/apngfuzz/apngdis-2.5.orig# gdb ./apngdis crash/crash.png
GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.04) 7.11.1
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from ./apngdis...done.
"/home/user/security/apngfuzz/apngdis-2.5.orig/crash/crash.png" is not a core dump: File format not recognized
(gdb) r crash/crash.png
Starting program: /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis crash/crash.png
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

APNG Disassembler 2.5

Reading 'crash/crash.png'...
=================================================================
==14864==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60200000ef91 at pc 0x00000040b1b4 bp 0x7fffffffd9b0 sp 0x7fffffffd9a0
READ of size 1 at 0x60200000ef91 thread T0
    #0 0x40b1b3 in compose6 /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis.c:469
    #1 0x40ca5f in LoadAPNG /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis.c:850
    #2 0x4017be in main /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis.c:1202
    #3 0x7ffff68a782f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #4 0x402048 in _start (/home/user/security/apngfuzz/apngdis-2.5.orig/apngdis+0x402048)

0x60200000ef91 is located 0 bytes to the right of 1-byte region [0x60200000ef90,0x60200000ef91)
allocated by thread T0 here:
    #0 0x7ffff6f02602 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x98602)
    #1 0x40bb97 in LoadAPNG /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis.c:632

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis.c:469 compose6
Shadow bytes around the buggy address:
  0x0c047fff9da0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9db0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9dc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9dd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9de0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa 00 06
=>0x0c047fff9df0: fa fa[01]fa fa fa 04 fa fa fa 01 fa fa fa 01 fa
  0x0c047fff9e00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9e10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9e20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9e30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9e40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
==14864==ABORTING
[Inferior 1 (process 14864) exited with code 01]
(gdb) disass crash/crash.pngQuit
(gdb) dis
disable      disassemble  disconnect   display      
(gdb) disass 0x40b1b3
Dump of assembler code for function compose6:
   0x000000000040a990 <+0>: lea    -0x98(%rsp),%rsp
   0x000000000040a998 <+8>: mov    %rdx,(%rsp)
   0x000000000040a99c <+12>:    mov    %rcx,0x8(%rsp)
   0x000000000040a9a1 <+17>:    mov    %rax,0x10(%rsp)
   0x000000000040a9a6 <+22>:    mov    $0xbb3f,%rcx
   0x000000000040a9ad <+29>:    callq  0x4112e0 <__afl_maybe_log>
   0x000000000040a9b2 <+34>:    mov    0x10(%rsp),%rax
   0x000000000040a9b7 <+39>:    mov    0x8(%rsp),%rcx
   0x000000000040a9bc <+44>:    mov    (%rsp),%rdx
   0x000000000040a9c0 <+48>:    lea    0x98(%rsp),%rsp
   0x000000000040a9c8 <+56>:    push   %r15
   0x000000000040a9ca <+58>:    push   %r14
   0x000000000040a9cc <+60>:    push   %r13
   0x000000000040a9ce <+62>:    push   %r12
   0x000000000040a9d0 <+64>:    push   %rbp
   0x000000000040a9d1 <+65>:    push   %rbx
   0x000000000040a9d2 <+66>:    sub    $0x48,%rsp
   0x000000000040a9d6 <+70>:    movzbl 0x88(%rsp),%r13d
   0x000000000040a9df <+79>:    mov    %rdi,0x18(%rsp)
   0x000000000040a9e4 <+84>:    mov    %r8d,0x28(%rsp)
   0x000000000040a9e9 <+89>:    mov    %r9d,0x2c(%rsp)
   0x000000000040a9ee <+94>:    add    $0x7,%r13d
---Type <return> to continue, or q <return> to quit---q
Quit
(gdb) i r
The program has no registers now.
(gdb) b *0x40b1b3
Breakpoint 1 at 0x40b1b3: file apngdis.c, line 469.
(gdb) r crash/crash.png
Starting program: /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis crash/crash.png
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

APNG Disassembler 2.5

Reading 'crash/crash.png'...

Program received signal SIGSEGV, Segmentation fault.
0xffffffffcd4013e0 in ?? ()

(gdb) i r
rax            0x1  1
rbx            0x1  1
rcx            0x60210000efd0   105694850248656
rdx            0xc0400001df2    13211319410162
rsi            0x60200000ef92   105690555281298
rdi            0x60200000ef91   105690555281297
rbp            0x2  0x2
rsp            0x7fffffffd9b8   0x7fffffffd9b8
r8             0x0  0
r9             0x1  1
r10            0x60200000eff0   105690555281392
r11            0x60200000ef91   105690555281297
r12            0x40000000   1073741824
r13            0x1  1
r14            0x1  1
r15            0x4  4
rip            0xffffffffcd4013e0   0xffffffffcd4013e0
eflags         0x10202  [ IF RF ]
cs             0x33 51
ss             0x2b 43
ds             0x0  0
es             0x0  0
fs             0x0  0
---Type <return> to continue, or q <return> to quit---
gs             0x0  0

(gdb) info registers rip
rip            0xffffffffcd4013e0   0xffffffffcd4013e0

4
==24222== ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000010000 at pc 0x4022bd bp 0x7fff9b142e90 sp 0x7fff9b142e88
READ of size 1 at 0x602000010000 thread T0
    #0 0x4022bc (/home/user/final/apngdis-2.5.orig/apngdis+0x4022bc)
    #1 0x40619a (/home/user/final/apngdis-2.5.orig/apngdis+0x40619a)
    #2 0x4012cd (/home/user/final/apngdis-2.5.orig/apngdis+0x4012cd)
    #3 0x7f677aadfec4 (/lib/x86_64-linux-gnu/libc-2.19.so+0x21ec4)
    #4 0x401734 (/home/user/final/apngdis-2.5.orig/apngdis+0x401734)
0x602000010000 is located 0 bytes to the right of 192-byte region [0x60200000ff40,0x602000010000)
allocated by thread T0 here:
    #0 0x7f677b0b141a (/usr/lib/x86_64-linux-gnu/libasan.so.0.0.0+0x1541a)
    #1 0x4059bb (/home/user/final/apngdis-2.5.orig/apngdis+0x4059bb)
Shadow bytes around the buggy address:
  0x0c047fff9fb0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9fc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9fd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9fe0: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
  0x0c047fff9ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c047fffa000:[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa010: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa020: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:     fa
  Heap righ redzone:     fb
  Freed Heap region:     fd
  Stack left redzone:    f1
  Stack mid redzone:     f2
  Stack right redzone:   f3
  Stack partial redzone: f4
  Stack after return:    f5
  Stack use after scope: f8
  Global redzone:        f9
  Global init order:     f6
  Poisoned by user:      f7
  ASan internal:         fe
==24222== ABORTING

2
Starting program: /home/user/final/apngdis-2.5.orig/apngdis crash.png

APNG Disassembler 2.5

Reading 'crash.png'...

Breakpoint 2, unpack (zstream=..., dst=dst@entry=0x6e1910 "", dst_size=dst_size@entry=192, src=src@entry=0x6e19e0 "x2b670", src_size=src_size@entry=14, h=2147483651, 
    rowbytes=rowbytes@entry=63, bpp=1 '
root@user-lap:~/final/apngdis-2.5.orig# export ASAN_SYMBOLIZER_PATH=/usr/bin/llvm-symbolizer-3.4 
root@user-lap:~/final/apngdis-2.5.orig# ASAN_OPTIONS=symbolize=1 ./apngdis crash.png 

APNG Disassembler 2.5

Reading 'crash.png'...
=================================================================
==25265== ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000010000 at pc 0x41c07d bp 0x7ffc560b3f20 sp 0x7ffc560b3f18
READ of size 1 at 0x602000010000 thread T0
    #0 0x41c07c in unpack /home/user/final/apngdis-2.5.orig/apngdis.c:185
    #1 0x41ff5a in LoadAPNG /home/user/final/apngdis-2.5.orig/apngdis.c:846
    #2 0x40281d in main /home/user/final/apngdis-2.5.orig/apngdis.c:1208
    #3 0x7fb4ca7e4ec4 (/lib/x86_64-linux-gnu/libc.so.6+0x21ec4)
    #4 0x402c84 in _start (/home/user/final/apngdis-2.5.orig/apngdis+0x402c84)
0x602000010000 is located 0 bytes to the right of 192-byte region [0x60200000ff40,0x602000010000)
allocated by thread T0 here:
    #0 0x412c0a in __interceptor_malloc (/home/user/final/apngdis-2.5.orig/apngdis+0x412c0a)
    #1 0x41f77b in LoadAPNG /home/user/final/apngdis-2.5.orig/apngdis.c:635
SUMMARY: AddressSanitizer: heap-buffer-overflow /home/user/final/apngdis-2.5.orig/apngdis.c:185 unpack
Shadow bytes around the buggy address:
  0x0c047fff9fb0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9fc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9fd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9fe0: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
  0x0c047fff9ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c047fffa000:[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa010: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa020: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fffa050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:     fa
  Heap righ redzone:     fb
  Freed Heap region:     fd
  Stack left redzone:    f1
  Stack mid redzone:     f2
  Stack right redzone:   f3
  Stack partial redzone: f4
  Stack after return:    f5
  Stack use after scope: f8
  Global redzone:        f9
  Global init order:     f6
  Poisoned by user:      f7
  ASan internal:         fe
==25265== ABORTING

1') at apngdis.c:171
171 {
(gdb) 
(gdb) 
(gdb) l
166       row[i] += row[i-bpp];
167   }
168 }
169 
170 void unpack(z_stream zstream, unsigned char * dst, unsigned int dst_size, unsigned char * src, unsigned int src_size, unsigned int h, unsigned int rowbytes, unsigned char bpp)
171 {
172   unsigned int    j;
173   unsigned char * row = dst;
174   unsigned char * prev_row = NULL;
175 
(gdb) l
176   zstream.next_out  = dst;
177   zstream.avail_out = dst_size;
178   zstream.next_in   = src;
179   zstream.avail_in  = src_size;
180   inflate(&zstream, Z_FINISH);
181   inflateReset(&zstream);
182 
183   for (j=0; j<h; j++)
184   {
185     switch (*row++) 
(gdb) l
186     {
187       case 0: break;
188       case 1: read_sub_row(row, rowbytes, bpp); break;
189       case 2: read_up_row(row, prev_row, rowbytes, bpp); break;
190       case 3: read_average_row(row, prev_row, rowbytes, bpp); break;
191       case 4: read_paeth_row(row, prev_row, rowbytes, bpp); break;
192     }
193     prev_row = row;
194     row += rowbytes;
195   }
(gdb) cont
Continuing.

Program received signal SIGSEGV, Segmentation fault.
unpack (zstream=..., dst=dst@entry=0x6e1910 "
==2720== ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60ae0003a81c at pc 0x41ee70 bp 0x7ffc84d157d0 sp 0x7ffc84d157c8
WRITE of size 4 at 0x60ae0003a81c thread T0
    #0 0x41ee6f in compose6 /home/user/final/apngdis-2.5.orig/apngdis.c:475
    #1 0x420025 in LoadAPNG /home/user/final/apngdis-2.5.orig/apngdis.c:853
    #2 0x40281d in main /home/user/final/apngdis-2.5.orig/apngdis.c:1208
    #3 0x7f4942135ec4 (/lib/x86_64-linux-gnu/libc.so.6+0x21ec4)
    #4 0x402c84 in _start (/home/user/final/apngdis-2.5.orig/apngdis+0x402c84)
0x60ae0003a81c is located 0 bytes to the right of 114716-byte region [0x60ae0001e800,0x60ae0003a81c)
allocated by thread T0 here:
    #0 0x412c0a in __interceptor_malloc (/home/user/final/apngdis-2.5.orig/apngdis+0x412c0a)
    #1 0x41f746 in LoadAPNG /home/user/final/apngdis-2.5.orig/apngdis.c:633
SUMMARY: AddressSanitizer: heap-buffer-overflow /home/user/final/apngdis-2.5.orig/apngdis.c:474 compose6
Shadow bytes around the buggy address:
  0x0c163ffff4b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c163ffff4c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c163ffff4d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c163ffff4e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c163ffff4f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c163ffff500: 00 00 00[04]fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c163ffff510: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c163ffff520: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c163ffff530: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c163ffff540: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c163ffff550: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:     fa
  Heap righ redzone:     fb
  Freed Heap region:     fd
  Stack left redzone:    f1
  Stack mid redzone:     f2
  Stack right redzone:   f3
  Stack partial redzone: f4
  Stack after return:    f5
  Stack use after scope: f8
  Global redzone:        f9
  Global init order:     f6
  Poisoned by user:      f7
  ASan internal:         fe
==2720== ABORTING

37777356", '7' <repeats 17 times>, "ϗ{mfca'''00H$2\t
root@laptop:~/security/apngfuzz/apngdis-2.5.orig# gdb ./apngdis crash/crash.png
GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.04) 7.11.1
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from ./apngdis...done.
"/home/user/security/apngfuzz/apngdis-2.5.orig/crash/crash.png" is not a core dump: File format not recognized
(gdb) r crash/crash.png
Starting program: /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis crash/crash.png
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

APNG Disassembler 2.5

Reading 'crash/crash.png'...
=================================================================
==14864==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60200000ef91 at pc 0x00000040b1b4 bp 0x7fffffffd9b0 sp 0x7fffffffd9a0
READ of size 1 at 0x60200000ef91 thread T0
    #0 0x40b1b3 in compose6 /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis.c:469
    #1 0x40ca5f in LoadAPNG /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis.c:850
    #2 0x4017be in main /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis.c:1202
    #3 0x7ffff68a782f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #4 0x402048 in _start (/home/user/security/apngfuzz/apngdis-2.5.orig/apngdis+0x402048)

0x60200000ef91 is located 0 bytes to the right of 1-byte region [0x60200000ef90,0x60200000ef91)
allocated by thread T0 here:
    #0 0x7ffff6f02602 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x98602)
    #1 0x40bb97 in LoadAPNG /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis.c:632

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis.c:469 compose6
Shadow bytes around the buggy address:
  0x0c047fff9da0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9db0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9dc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9dd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9de0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa 00 06
=>0x0c047fff9df0: fa fa[01]fa fa fa 04 fa fa fa 01 fa fa fa 01 fa
  0x0c047fff9e00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9e10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9e20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9e30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9e40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
==14864==ABORTING
[Inferior 1 (process 14864) exited with code 01]
(gdb) disass crash/crash.pngQuit
(gdb) dis
disable      disassemble  disconnect   display      
(gdb) disass 0x40b1b3
Dump of assembler code for function compose6:
   0x000000000040a990 <+0>: lea    -0x98(%rsp),%rsp
   0x000000000040a998 <+8>: mov    %rdx,(%rsp)
   0x000000000040a99c <+12>:    mov    %rcx,0x8(%rsp)
   0x000000000040a9a1 <+17>:    mov    %rax,0x10(%rsp)
   0x000000000040a9a6 <+22>:    mov    $0xbb3f,%rcx
   0x000000000040a9ad <+29>:    callq  0x4112e0 <__afl_maybe_log>
   0x000000000040a9b2 <+34>:    mov    0x10(%rsp),%rax
   0x000000000040a9b7 <+39>:    mov    0x8(%rsp),%rcx
   0x000000000040a9bc <+44>:    mov    (%rsp),%rdx
   0x000000000040a9c0 <+48>:    lea    0x98(%rsp),%rsp
   0x000000000040a9c8 <+56>:    push   %r15
   0x000000000040a9ca <+58>:    push   %r14
   0x000000000040a9cc <+60>:    push   %r13
   0x000000000040a9ce <+62>:    push   %r12
   0x000000000040a9d0 <+64>:    push   %rbp
   0x000000000040a9d1 <+65>:    push   %rbx
   0x000000000040a9d2 <+66>:    sub    $0x48,%rsp
   0x000000000040a9d6 <+70>:    movzbl 0x88(%rsp),%r13d
   0x000000000040a9df <+79>:    mov    %rdi,0x18(%rsp)
   0x000000000040a9e4 <+84>:    mov    %r8d,0x28(%rsp)
   0x000000000040a9e9 <+89>:    mov    %r9d,0x2c(%rsp)
   0x000000000040a9ee <+94>:    add    $0x7,%r13d
---Type <return> to continue, or q <return> to quit---q
Quit
(gdb) i r
The program has no registers now.
(gdb) b *0x40b1b3
Breakpoint 1 at 0x40b1b3: file apngdis.c, line 469.
(gdb) r crash/crash.png
Starting program: /home/user/security/apngfuzz/apngdis-2.5.orig/apngdis crash/crash.png
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

APNG Disassembler 2.5

Reading 'crash/crash.png'...

Program received signal SIGSEGV, Segmentation fault.
0xffffffffcd4013e0 in ?? ()

(gdb) i r
rax            0x1  1
rbx            0x1  1
rcx            0x60210000efd0   105694850248656
rdx            0xc0400001df2    13211319410162
rsi            0x60200000ef92   105690555281298
rdi            0x60200000ef91   105690555281297
rbp            0x2  0x2
rsp            0x7fffffffd9b8   0x7fffffffd9b8
r8             0x0  0
r9             0x1  1
r10            0x60200000eff0   105690555281392
r11            0x60200000ef91   105690555281297
r12            0x40000000   1073741824
r13            0x1  1
r14            0x1  1
r15            0x4  4
rip            0xffffffffcd4013e0   0xffffffffcd4013e0
eflags         0x10202  [ IF RF ]
cs             0x33 51
ss             0x2b 43
ds             0x0  0
es             0x0  0
fs             0x0  0
---Type <return> to continue, or q <return> to quit---
gs             0x0  0

(gdb) info registers rip
rip            0xffffffffcd4013e0   0xffffffffcd4013e0

4%pre%2%pre%1", dst_size=dst_size@entry=192, 
    src=src@entry=0x6e19e0 "x2b670", src_size=src_size@entry=14, h=2147483651, rowbytes=rowbytes@entry=63, bpp=1 '%pre%1') at apngdis.c:185
185     switch (*row++) 
(gdb) 

1", dst_size=dst_size@entry=192, 
    src=src@entry=0x6e19e0 "x2b670", src_size=src_size@entry=14, h=2147483651, rowbytes=rowbytes@entry=63, bpp=1 '%pre%1') at apngdis.c:185
185     switch (*row++) 
(gdb)

Qui con i simboli:

%pre%

Ultimo, ma non meno importante, un link a un buon tutorial su Heap Buffer Overflow su Linux che è reale sarà fantastico!

Ecco il codice completo del programma in questione:

link

Aggiornamento 29.02.2016

Trovato una scrittura di 4 byte. Sembra che ci sia una chiamata malloc in LoadAPNG con valore controllato dall'utente. È possibile utilizzare la tecnica "The House of Force"?

%pre%

Aggiornamento 07.02.2017

Come richiesto da @grepNstepN

%pre%     
posta android_dev 26.02.2016 - 12:45
fonte

2 risposte

3

Capisco da dove vieni, ho fuzz vari prodotti (chrome, flash, tra le altre cose). L'ultima cosa che vuoi fare è dare via una bounty o una consulenza (appoggio il precedente altro di il ultimo , soprattutto considerando cosa è successo ad Aaron Schwartz ).

Pensaci: in questo caso apngdis può produrre una possibile vulnerabilità del parser o del formato di file in libpng , che viene utilizzato da Chrome, Firefox, Webkit (iOS, OSX), ecc. Tutti i suddetti hanno dei bug bounties. Per lo meno, Google offre ricompense per proteggere i progetti open source . Non so se apngdis sia usato direttamente in qualsiasi prodotto.

Considerato quanto sopra, se hai bisogno di aiuto, puoi fare ciò che ho fatto in passato riguardo a diverse vulnerabilità che ho trovato:

  1. Chiedi aiuto a qualcuno che ha troppa reputazione per rubare i tuoi doni / consigli (# corelan / Peter Van Eekhoutte mi viene in mente), ma offri un ringraziamento / ringraziamenti nella consulenza ... curiosità / una sfida / fama / altruismo è un grande motivatore
  2. Chiedere a qualcuno di firmare una NDA per assicurarsi che non si verifichino furti. In cambio, tuttavia, dovrai concedere una parte della generosità / gloria (un tiro di coda nella consulenza o persino nella co-paternità)
  3. Esamina le esercitazioni precedenti e sfrutta le annotazioni, cercando le somiglianze
  4. Chiedi aiuto senza offrire nulla in cambio su stackexchange, che è piuttosto irrispettoso. Almeno se si tratta di una rivelazione pubblica, ringraziare chi aiuta ... c'è un motivo per cui non vedi più persone che chiedono aiuto per lo sfruttamento su stackexchange.

Se scegli il n. 4, avremo bisogno di quanto segue da parte tua:

Abbiamo bisogno dello smontaggio della lettura in [apngdis + 0x4022bc], dell'istruzione precedente e dello stack di chiamate. Lo stesso vale per la scrittura (disassemblaggio di RIP, istruzione RIP-1, stack di chiamate)

Considera che interpretare l'output di ASan non ti aiuterà necessariamente con lo sfruttamento senza il suddetto. Ad esempio: 

==24222== ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000010000 at pc 0x4022bd bp 0x7fff9b142e90 sp 0x7fff9b142e88
READ of size 1 at 0x602000010000 thread T0
#0 0x4022bc (/home/user/final/apngdis-2.5.orig/apngdis+0x4022bc)
...
    
risposta data 31.08.2016 - 03:40
fonte
2

CVE-2017-6193 è stato prenotato per questa vulnerabilità specifica (presente nella versione 2.8). Il tuo nome è stato incluso come scopritore e co-contributore.

Domani questo post sarà online per un anno, e al momento della scrittura è stato visto quasi 2000 volte.  Quindi, per impedire a qualcuno di abusare di questo, e visto che i dettagli sono ancora pubblici, spero che non ti dispiaccia che mi sono preso la libertà di eseguire apngdis in un cluster afl-fuzz per ricostruire il problema per la segnalazione.

Tra la riscoperta di queste corruzioni della memoria, ce n'era anche una nel descrittore della dimensione del blocco, per non parlare di un overflow del libro di testo nella gestione del parametro filename.

Ho eseguito il debug dei problemi e avvisato lo sviluppatore. Dopo aver spiegato la gravità della situazione che si è verificata alle sue spalle, è stato molto reattivo ed è ora abbastanza gentile da lavorare sulla versione 2.9.

Il danneggiamento della memoria nella funzione compose_frame è ancora presente nell'ultima versione 2.8 ed è facile da spiegare. memcpy () viene invocato su un gruppo di zeri con una lunghezza fornita dall'attaccante, entro alcuni vincoli.

Innanzitutto, dopo aver verificato che sia effettivamente un file PNG e un campo di dimensione IHDR, il valore viene caricato dal file: 

    w0 = w = png_get_uint_32(chunkIHDR.p + 8);
    h0 = h = png_get_uint_32(chunkIHDR.p + 12);

Quindi, dopo aver verificato che i valori siano inferiori a const unsigned long cMaxPNGSize = 1000000UL; , viene chiamato quanto segue: 

compose_frame(frameCur.rows, frameRaw.rows, bop, x0, y0, w0, h0);

Che consistono in: 

void compose_frame(unsigned char ** rows_dst, unsigned char ** rows_src, unsigned char bop, unsigned int x, unsigned int y, unsigned int w, unsigned int h)
{
  unsigned int  i, j;
  int u, v, al;

  for (j=0; j<h; j++)
  {
    unsigned char * sp = rows_src[j];
    unsigned char * dp = rows_dst[j+y] + x*4;

    if (bop == 0)
      memcpy(dp, sp, w*4);

Memcpy viene richiamato e inizia felicemente a copiare alcuni milioni di zeri prima di entrare nella memoria non mappata.: 

Breakpoint 1, compose_frame (rows_dst=0x7fffef54f010, rows_src=0x7ffff3150010, bop=0 '
    w0 = w = png_get_uint_32(chunkIHDR.p + 8);
    h0 = h = png_get_uint_32(chunkIHDR.p + 12);

0', x=0, y=0, w=983040, h=983040) at apngdis.cpp:77
77          if (bop == 0)
(gdb) n
78            memcpy(dp, sp, w*4);
(gdb) print dp
$1 = (unsigned char *) 0x55555576f910 ""
(gdb) print sp
$2 = (unsigned char *) 0x55555576f2a0 ""
(gdb) print w

Su Windows x86, questo compila al seguente assembly e possiamo vedere che la copia avviene da ESI a EDI:

.text:011FFA90 loc_11FFA90: ; CODE XREF: .text:011FFAEBj .text:011FFA90 movdqa xmm0, oword ptr [esi] .text:011FFA94 movdqa xmm1, oword ptr [esi+10h] .text:011FFA99 movdqa xmm2, oword ptr [esi+20h] .text:011FFA9E movdqa xmm3, oword ptr [esi+30h] .text:011FFAA3 movdqa oword ptr [edi], xmm0 .text:011FFAA7 movdqa oword ptr [edi+10h], xmm1 .text:011FFAAC movdqa oword ptr [edi+20h], xmm2 .text:011FFAB1 movdqa oword ptr [edi+30h], xmm3 .text:011FFAB6 movdqa xmm4, oword ptr [esi+40h] .text:011FFABB movdqa xmm5, oword ptr [esi+50h] .text:011FFAC0 movdqa xmm6, oword ptr [esi+60h] .text:011FFAC5 movdqa xmm7, oword ptr [esi+70h] .text:011FFACA movdqa oword ptr [edi+40h], xmm4 .text:011FFACF movdqa oword ptr [edi+50h], xmm5 .text:011FFAD4 movdqa oword ptr [edi+60h], xmm6 .text:011FFAD9 movdqa oword ptr [edi+70h], xmm7 .text:011FFADE lea esi, [esi+80h] .text:011FFAE4 lea edi, [edi+80h] .text:011FFAEA dec edx .text:011FFAEB jnz short loc_11FFA90

    
risposta data 25.02.2017 - 06:08
fonte

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I browser sono ancora vulnerabili alla cucina Cross-Site? Hardware di sourcing che è meno probabile che contenga backdoor